How does lettuce reproduce?

The water lettuce is a doubled sided aquarium plant. On one side, it can be quite ornamental and instrumental in the fight against algal bloom, but on the other hand, the plant itself can be just as dangerous as the algae you want to so desperately get rid of.

Left unchecked the water lettuce can be more of the problem than a solution, so what exactly makes this plant so special and why should you be wary of it?

The water lettuce or Pistia stratiotes is an aquatic plant that was initially discovered at the waters of the Nile. They originally come from Africa, and over the course of time, they have spread all over America and Europe.

They are especially popular in water gardens and open aquariums because of their beautiful rosette leaves and potency against algae; they also compete with other plants over nutrients.

Despite their beauty and usefulness, they have suffered a somewhat negative reputation. They are notoriously gifted at reproduction and they have been classified as weeds by several countries worldwide.

They float on the water surface with the help of their leaves and when left unchecked they can outgrow and cover up the entire water surface, eventually starving the other plants and fishes.

When grown and tended to properly, they can be quite instrumental in keeping things in order. They regulate the nitrate concentrations in the water and keep the fish alive and protected.


Dwarf Water Lettuce in Aquarium

Dwarf water lettuce is the more tolerable and manageable variant of the water lettuce. There have been speculations as to whether they are an established species on their own but the results are far from conclusive.

The popular belief is that they are a variation of the water lettuce that is triggered when the nodes are introduced into a more nutrient deficient environment. Most individuals prefer this to the more prevalent type of water lettuce.

This one, as it turns out, is considerably easy to look after and their roots don’t grow as much. they make fantastic ornaments without the added risk of unchecked growth and they perform all the functions normal water lettuce should.

Water lettuces can be quite a problem when they are left unchecked. They are a fantastic addition to the tank because they feed on nitrates, but are wild and oftentimes uncontrollable; however, they are not completely irredeemable.

They help the fish in ways you don’t even understand. They provide shade for the smaller fishes; they also soak in nitrates which could be potentially lethal to the fishes. Water lettuces are perennial plants that flower rarely and adapt well to semi-temperate regions.

In Florida, it’s illegal to own and house a water lettuce without the proper documentation and it’s punishable by a steep fine.

They are considered dangerous because of just how well they spread with little to no other nutrients apart from nitrates. They are considered a public nuisance in this state and are dealt with using every means in the book.

Herbicides, beetles, larvae, and mechanical removal have been used in the past to rid public ponds and larger bodies of water of these atrocious plants but the question is, does the good outweigh the bad?

Do the many advantages of this insanely invasive plant more than make up for the potential troubles it will definitely stir up? quite frankly, no.

The plant might be useful and powerful enough to keep the algae at bay, but if you are able to get your hands on the dwarf plant of the water lettuce, then it would be in your best interest to go with the plant that is infinitely easier to control and maintain.

Facts about the Water Lettuce

The water lettuce is a tropical plant

The water lettuce was found in Africa; this means that the plant might be only able to grow and flourish in more temperate environments.

Like a great deal of tropical marine and plant life, the water lettuce is dependent on the temperature of locations close to the equator.

This means that this plant can’t grow in just any temperature, it prefers warmer, more temperate waters, and this usually translates to a tropical tank setup.

The water lettuce is a tropical plant and this means that it needs a lot of light and heat. The water needs to be around 60 degrees and the surface temperature needs to range from 70 to 80 degrees Fahrenheit and these numbers have to be constant.

Also Check: Pothos In Fish Tank

It will not survive most winters

The plant cannot deal with the cold, one little bit. It withers and dies almost immediately and it’s almost impossible to keep it alive during winters.

Despite most attempts to keep it healthy and alive during cold winter months, it ends up withering halfway through winter. In my experience, transferring it to a more temperate or warm room is bound to extend its life span considerably but ultimately it is futile. They almost always never make it through those cold months.

They do not require a soil

As they grow, they have wispy roots that extend from the plants and sometimes grow up to an inch or two into the water. the water lettuce roots are its main source of sustenance and they can go their entire life without needing as much as a grain of sand or soil.

Their leaves are unique

The water lettuce leaves are more peculiar than most. It has a unique rosette pattern that is truly aesthetic. The leaves area pale and yellow-green and are fan-shaped and adjoining like ribs.

The leaf surface is covered in fine hairs that were designed to retain water and increase the overall buoyancy of the plant on any given water surface. The leaves of the lettuce are more intricately adjoined towards the plant’s root and they form a dense mat over the water surface eventually.

The leaves of a fully matured lettuce can reach up to six inches and the hairs of the plant can get less dense as you move closer to the center of the plant.


One of the funniest things about this water plant is that it actually has nothing to do with actual lettuces. They are called water lettuces because they look a lot like actual lettuce.

The first few days are always a struggle when trying to introduce these guys to a tropical aquarium setup. they usually struggle for a bit and try to acclimate themselves with the tank water and when they eventually do, it takes a minute or two for them to get growing really. This can be somewhat problematic at first, but when they really get going there is no stopping them.

Water lettuces reproduce in one of two ways; Asexually and sexually.

When the water lettuce reproduces asexually, then, it reproduces in a mother-daughter fashion. A new plant is born and but still attached to the old one by a stolon.

The stolon usually sticks out of place and when the replication process has repeated itself an absurd number of times, the plants eventually form a dense mat that is fast and strong enough to cover the entire surface of relatively large bodies of waters in a short time.

Asexual reproduction is the main way that the plant reproduces. The sexual way is also possible, but very unlikely; it only happens in rare situations.

The sexual method deals largely with cross-pollination. The male flower and female flowers usually belong to separate plants and when they somehow manage to reach one another and cause fertilization, a small greenish seed is produced. This begins the life of a new plant and eventually a new mat.

The seeds of the water lettuce usually eventually change from a green to brown when it ripens. Sexual pollination is more likely in dense mats and the wind is usually the agent of pollination in instances like these.

The seed of the plants usually float on the water surface for a relatively short time then eventually sink and reemerge after a few days of waiting. They will resurface as far as the water is not too cold; they are surprisingly resilient once they are well dug in.

More: Duckweed in Aquarium

Are water lettuce poisonous

It depends on who you ask. If you ask the devout aquarium enthusiast, he might give you a clear answer like no; which is technically the truth but that is if you are a hobbyist.

The government, however, classify the plant as dangerous and potentially harmful to all life. This is a bit hefty considering the plant is just aquatic and in no way actually poisonous.

The sites where they are found usually come with a caution sign to ward off all interested parties and it has been listed amongst the country’s list of noxious plants. Water lettuce is edible to some species of fish and cattle seem to stomach them fine, so why were they classified as dangerous and why does the government hate them so much.

Why the government hates water lettuces

When water lettuces start growing healthily in a particular location, they tend to choke every other plant out. they will compete over the resources and eventually cause other plants to wither.

They greatly reduce light penetration, reduce oxygen concentration and mess up the pH of the large water bodies like communal ponds.

They are the harbingers of disease. Malaria-carrying mosquitoes have been known to frequently appear in areas and bodies of waters that have been overrun with water lettuce.

Uses of the Water Lettuce

This is a great question? Given the never-ending list of reasons why you shouldn’t attempt to cultivate or add this plant to your aquarium, there are some fairly acceptable reasons.

They aren’t just wild weeds that are impossible to control, on the contrary, a lot of aquarium hobbyist have succeeded in cultivating and controlling this unruly plant.

They have weighed their options and decided to deal with the challenges that come with this dominant plant. Some of the uses are;

They are ornamental

Never underestimate the beauty of this weirdly shaped plant. It is beautiful and makes a memorable addition to the surface of the aquarium.

They are edible

As I said, they have become past time meals for the herbivores of the tank. , in particular, have been known to give a strong appetite for the plant and have been known to kill them off entirely when they are still young.

They reduce the probability for an algal bloom

Algae is probably the most disturbing and irritating plant life that you can house in your aquarium. Left unchecked, they can really be a problem. One of the best ways to stop them in their tracks is by adding other plants to the aquarium, and one of such plants is the water lettuce.

They have been known to considerably limit algal blooms in numerous tanks and this might be one of the reasons that they are one of the preferred methods to prevent algae despite the obvious risks involved.

It can be used to keep the water pure. This little advantage might be unknown to most aquarium owners, but it might just be the greatest and noticeable advantage of the plant.

It has the ability to clear out mercury from water by absorbing them. they can deal with a fair amount of mercury but are hopeless when the concentrations are too high.

States that prohibit the sale and transportation of the water lettuce

Although it has garnered a lot of attention and appreciation amongst some circles, it still remains a weed and a source of concern in others.

In certain states in America, they still remain a threat to marine life and are categorized as noxious weeds. They spread like a wildfire once they have properly dug in and they are quite difficult to eradicate because of their volume.

How to deal a water lettuce infestation

Water lettuces can be quite the nuisance when they are left to themselves. Usually, there are a handful of different ways to deal with them, the first being letting nature take its course.

However, this is problematic because it’s not an option in more temperate regions. They are simply not cold enough to kill them during the winter months.

Over the years, people have devised more practical and effective ways to deal with the plant without having to depend on the ever-changing seasons.

The use of different well-known insects in their complete annihilation has been popular in instances of mass scale infestation. The Neodydronomous pulchellus weevil has been used as a biological agent of containing the spread of the plant.

Another insect that is particularly known for its palette for the otherwise inedible plant is the Spodoptera pectinicornis. It’s a caterpillar that is native to Thailand and it has been used by several state authorities and other concerned third parties to curb the spread of the plant.

The use of well-known herbicides like Shoreline defense is also an alternative to the weevil solution. They are more effective but ultimately detrimental to the aquarium residents.

They are more effective against infections in large bodies of waters like ponds, however, using them in a more enclosed body of water will no doubt put both the plants and the fish in danger.

There is also the classic, all-natural weeding. It has proven to be the most effective method when trying to control them in an aquarium setup and they tend not to completely eliminate the plant from the aquarium. This way you keep the number of lettuces that you are comfortable with and not endanger your fish.

Planting the water lettuce

Although it’s true that the water lettuce tends to hog all the nutrients for itself, it’s possible for them to exist in association with other aquatic plants. They can go a long way to improve the overall aesthetic of the entire tank.

When trying to add the water lettuce to your tank, there are some rules to follow to make sure that they survive the initial introduction to the foreign tank.

They are not quite as resilient as they are made out to be. In most cases, they rarely survive without some help from the outside.

They need a little sunshine

Like all plants, they need sunlight for photosynthesis. Cultivated water lettuces, however, need sunlight introduced to them in levels. They have to be gently introduced to sunlight.

They might burn and perish if they are just introduced to direct sunlight immediately. An artificial light source or shaded exposure is recommended. A couple of T5 or T8 bulbs should be just fine in the first few weeks.

You need to watch the humidity

Water lettuces are particular about their humidity, they need lots of it to grow naturally and healthily. If the room is particularly lacking humidity, you could consider covering the tank.

That will provide enough humidity to keep the plants growing strong. I know that this might not be the best for a planted tank, but the cover-up will only last a few weeks.

Tips for keeping water lettuce from overtaking the tank

Although they can provide some form of shade for the smaller fish, they can quickly become a nuisance because of their speedy reproduction. The only way to prevent this eventuality is to do a little weeding every week or so.

They might not look like they need it, but all it takes is a few days and they’ll completely overrun the tank. Cutting a few stolons off every week is enough to keep them at check for now.

If you are looking to get rid of them all, then wait patiently till the winter. The weather is considerably colder and they will die out in the first month or so.

Question: Can I bring my water lettuce indoors for the winter and put them in my fish aquarium until Spring?

Answer: Some questions don’t have a clear cut answer, but the short of this answer is YES, you can bring water lettuce indoors for the winter months. With that advice let’s clarify the answer. If you were to bring you water lettuce in to keep in your aquarium until Spring you have some things you need to consider…

Water lettuce will need some pretty strong lighting to do well indoors, so lighting really needs to be good. Also the water lettuce will need some clearance if it is floating on the top of your fish tank. It will not work if you try to squeeze it under a tank lid so you will probably have to leave your aquarium with an open top and your strong lighting suspended above the tank. Given those conditions your water lettuce will probably do fairly well until Spring. Other indoor options would be keeping your water lettuce in some type of greenhouse enclosure in shallow pools, or kiddie pools. You will still need to provide some warmer temperatures of 70+F, very good lighting as well. Water lettuce enjoys alot of sun!

I think the best advice however; for the backyard water garden hobbyist is to compost your water lettuce after the first frost and buy new water lettuce the next season. Water lettuce is readily available and inexpensive. The cost of keeping water lettuce year round may be quite a bit more than simply purchases new plants each season. I generally advise using water lettuce as an annual in your water garden, and bring them in for some short lived indoor aquatic plant features when temperatures drop, or compost them.

Whichever option you opt for, enjoy your pond keeping experience!

Keep it pondy! -Mike

The LOVEYOURPOND Blog is written by Mike Gannon of Full Service Aquatics located in Summit, NJ. Mike is an award winning pond, water garden, and water feature builder. Always “In The Pursuit Of All Things Aquatic” Mike has been a lifelong hobbyist and providing professional services since 1995. Mike is the creator of The Pond Hunter video series seen on Youtube and has made several television appearances on Networks such as HGTV and the DIY Network. He also hosts the Pond Hunter Radio Broadcast. You can see what else Mike is up to at the following sites:

All copy rights to this material is solely owned by Mike Gannon.

Water Lettuce Facts, Care, Planting, & Hardiness (Pistia stratiotes)

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Water lettuce is a hardy, thick-growing floating aquatic plant which is loved by wildlife.

Water lettuce is a floating, herbaceous perennial plant found across the globe in tropical and subtropical regions. Water lettuce, also called water cabbage or Nile cabbage, is aptly named and looks like a head of the leafy greens.

Water lettuce was first described along the Nile River around 2,000 years ago. References to the plant were made in both Ancient Egyptian hieroglyphics and the writings of Ancient Greek botanists. Water lettuce has since been found in bogs, lakes, and marshes of every continent except Antarctica.

Water lettuce is popular for those with water gardens because its presence inhibits the growth of algae and cleans the water. It has even been proven effective at removing heavy metal toxins like zinc and cadmium from a water supply.

Water Lettuce Fact Sheet: PLANT TYPE Tropical herbaceous perennial HARDINESS ZONES USDA 8-10 LIGHT REQUIREMENTS Full sun or Partial Shade BLOOM COLOR White or yellow (inconspicuous) BLOOM PERIOD June to September MAXIMUM GROWTH Spread Up To 30 cm (12″) PLANTING DEPTH Water’s surface WATER QUALITY pH 6.5-7.2; 2.5 ppt salinity

Water Lettuce Growth & Hardiness Considerations

Water lettuce grows in rosettes on the water’s surface with thick, soft leaves that can reach 15 cm (6 in) in length. One rosette can reach a diameter of around 30 cm (12 in) and a height of 10cm (4 in). Dense feathery roots extend up to 1 meter (39 in) below the surface of the water and provide ample shelter for small fish. New growth usually occurs with the development of smaller daughter plants connected to the original growth via stolons.

Water lettuce is a floating perennial plant found across the globe in tropical and subtropical regions. It requires growth temperatures of at least 15o C (59o F), and grows best around 22 to 30o C (72-86o F). This plant is particularly sensitive to dissolved minerals and requires water with a salt content of 2.5 ppt or less and an absence of lime.

Water lettuce produces small, inconspicuous flowers in the center of the plant in late summer through early autumn. They produce massive quantities of seeds, which can sink to the bottom of the water and survive winter in temperate climates. Although not winter hardy, water lettuce seeds can survive under water at temperatures of at least 4 o C (39 o F) for two months.

How to Plant Water Lettuce:

Most water lettuce is sold by head or in small groups. Any yellow leaves should be removed before planting. To plant, water lettuce can be simply spread across the surface of your pond during late April after the last frost of the season. Water lettuce grows best if it is not constantly being moved around. You can enclose your water lettuce using a floating plastic hoop, fishing line, or rocks. Although tropical plants, water lettuce grows best in the early part of the summer when temperatures reach at least 15.5 o C or 60 o F. It is a good idea to provide partial shade during midday when the temperatures are at their peak, especially if you live in a hot climate.

How to Care for Water Lettuce:

Water lettuce grows rapidly and requires the removal of excess plants to prevent overcrowding and nutrient limitation. There are two different strategies to accomplish this. Removing the small daughter plants will promote additional growth and is ideal for propagating plants. On the other hand, removing the larger plants will slow down growth and decrease the required maintenance.

It is recommended to bring water lettuce inside over winter. To do this, place several plants in wet, sandy loam before the first frost and store in an area with bright light and a temperature of at least 10 o C or 50 o F. Some gardeners have also had success overwintering by placing plants in a clear goldfish bowl filled with rainwater and storing in full sunlight at 50 o F (10 o C) or higher.

If a pond is particularly small, water lettuce may consume certain nutrients and start to turn yellow. There are several ways to remedy this including floating the failing plants in dissolved Miracle Grow for several hours, applying the solution of the depleted nutrient to the pond, and treating the pond with a commercial nutrient booster.

Additionally, if you use a pond skimmer, be sure to regularly check that no water lettuce has floated into the system, which can damage the pump. Water lettuce may also be eaten and killed by pond fish. For this reason, it may be a good idea to contain water lettuce in aquatic baskets or separate the problem fish with a solid boundary.

Is Water Lettuce Toxic or Invasive

Water lettuce is native to most of the tropical world, but it is considered a pest because of its penchant for growing out of control. Water lettuce can create an economic toll on an area by choking irrigation and drainage systems and by preventing boating and fishing access in lakes, canals, and rivers—an important tourist draw. Water lettuce has also been identified as a risk for taro and rice fields. Severe ecological consequences have also been described. Water lettuce can block the air-water interface of a body of water, which limits gas exchange and causes dissolved oxygen levels to plummet. Additionally, the leaves, which are often filled with stagnant water, are ideal breeding environments for mosquitos.

Although there is some disagreement on whether water lettuce is native to the United States, the explorer William Bartram described large growths of the aquatic plant limiting their boat access through a creek in 1765. Regardless, water lettuce is prohibited in the states of Florida, Louisiana, Mississippi, and Texas, and the country of New Zealand.

Water lettuce is toxic if ingested by small animals like pets or even children. It contains a poisonous compound, calcium oxalate, which burns the mouth and may lead to kidney damage.

Will Fish Eat Water Lettuce?

It is not well documented which organisms enjoy eating water lettuce. However, many home gardeners have found that their fish can kill their water lettuce plants by eating its roots.

Dwarf water lettuce turning white and yellow

This is insect damage of some kind the physical evidence for this is overwhelming…notice how certain parts of the leaves look as if a large semi circular mouth has taken a bite what this actually is is the mechanical damage of an insects feeding habits,taking tiny bites all the way across the leaf from edge to edge until the unsupported portion of the leaf falls away.

I could be wrong but it looks as if you’ve more than one type. Other damage looks more indicative of a leaf boring type insect but this could also be diseased plants which can actually be contracted by plant pest insects but my money is on insect damage.

  • Remove all affected foliage
  • rinse each plant thoroughly
  • return to water …
  • then dose the pond with a fairly liberal amount of fertilizer

Careful though, a fine line exists between a liberal dose to encourage growth in plants struggling back to health and an algae explosion that will be a much bigger problem.

The aquarium salt is not a problem so long as you don’t add any more. It’s not filtered out and can only be decreased by removing a quantity of water and replacing it with fresh. It will eventually dissipate on its on.

Every fish you mentioned will benefit from a small amount of salt in their water. Every now and then it will not harm them in the slightest as long as you follow instructions on labeling to the letter. Check to see what kind of tolerance the water lettuce has and at what specific gravity salt because problematic for the plant. Salt is sodium is on the nutrient list that planst need at least tiny amounts of for total overall health.

I have a 125 gallon soft shell turtle set up with duckweed,frogbit salvinia and water lettuce and it’s is salted regularly and the plants do just fine. I fish out a couple of large nets full every two weeks or so because the growth is unbelievably prolific. Not saying the salt is the cause at all probably turtle poop…and extra fertilizer…but they do excellent even with the salt in the water. It’s barely measurable with a hydra meter if you do it right.

Upon closer examination of your photo a small insect is actually visible in amongst the water lettuce. It looks like an aqua beetle of some kind but maybe just dead terrestrial insect that stumbled into the pond. Sample any and all insects you find in pond to identify them you can incorporate appropriate control measures.

Quick Stats
Care Level: Moderately Difficult
Water Conditions: 6.5-7.2 pH and Soft to Moderately Hard
Lighting Requirements: Medium
Temperature: 70 to 80 °F (21-27°C)
Maximum Size: 10 inches (25.5 centimeters)

Water lettuce (Pistia stratiotes), also referred to as water cabbage, or Nile cabbage, is an aquatic plant that can be surprisingly difficult to grow in the home aquarium. But with a little bit of hard work, these plants form an attractive maze of hanging roots, which creates the perfect environment for fry and skittish fish.

It is believed that water lettuce is native to Africa, though there is no consensus on where it originated from on the continent. It was first recorded on the Nile River, near Lake Victoria. In the ensuing years after its discovery, it has spread around the globe, and presents a very real threat to native vegetation and fish. In fact, it is illegal to own or transport water lettuce in certain states and countries, and anyone looking to purchase these plants should first check local regulations.

Water lettuce grows up to 10 inches across (25.5 centimeters), though it tends to be smaller in the home aquarium. Its leaves have no stem and their surface is covered in short, soft hairs, which help to trap air and increase the buoyancy of the plant.


Water lettuce grows floating on the surface water, and its leaves form a rosette, with dense, submerged roots beneath it. These plants grow like a weed outdoors, but they can be very challenging to grow in the home aquarium. However, if they are provided with the right conditions, they can completely overrun an aquarium, and in most cases, it’s a good idea to remove a few plants during weekly tank maintenance.

A regular set of full spectrum T5 or T8 bulbs is sufficient to grow these plants, but as most water lettuce available for sale are grown in shade, they should slowly be introduced to full light. If they are placed under strong lights immediately after being purchased, it’s likely the leaves will scorch, and the plant will struggle to grow.

Another problem that makes growing these plants indoors problematic is lack of humidity. If the room they are being grown in has low humidity, a person may want to consider adding a cover to the aquarium – even if it’s not optimal for a planted tank.

Water lettuce can propagate both sexually and asexually, though sexual reproduction is exceedingly rare in the home aquarium. The flowers are tiny and are located at the center of the plant. Each plant will only have either male or female flowers. If successful fertilization occurs, a small, many-seeded green berry will form.

Asexual reproduction is far more common in the home aquarium, and smaller daughter plants will form floating beside their mother plant, connected by a short stolon. When they reproduce with this method, they can form dense mats, and it’s important to not let them completely cover the surface of an aquarium. If they do, they will prevent light from reaching other plants, and can even suffocate the fish beneath them.

When these plants are first purchased, they will often have numerous dead, yellow leaves. These leaves should be removed before adding the plants to the aquarium, ensuring the plants is primed for rapid growth. It will often start out slowly, but will begin to spread and grow very fast when mature.


Water lettuce is compatible with most fish, although larger fish like cichlids may damage it. However, it should be completely avoided in any tank containing goldfish or any other large herbivore fish, as they tend to eat the roots, and even the plant itself.

Growing Water Lettuce in Aquariums with Current

If a person is using a hang-on-back filter, it can be difficult to get these plants started. Often, they will be pushed around the tank by the current, or even submerged if they float under the outflow of the filter.

The best way to deal with this problem is to create a ‘roped off area’ for the plant. The way that I handled this in the past, was by using clear air tubing strung across the top of the aquarium. It was affixed with suction cups on either side of the tank just under the surface. This allows the plants to grow and form a mat, and once they are in a dense mat, they should stay relatively stationary – even with a significant amount of current.

Water lettuce, Pistia stratiotes.

Water gardens can contain a wide variety of types of plants, from submerged to emergent to free-floating with no contact with the substrate. One of those plants that float on the surface of the water is Pistia stratiotes, commonly called water lettuce because of its superficial resemblance to the green leafy vegetable. It is also occasionally called water cabbage or Nile cabbage, but is not edible. This species in the arum family (Araceae), the only one in the genus, likely originated in Africa or tropical America, but its origin is difficult to ascertain for sure. It was first described from Lake Victoria in Africa, but its distribution is now pantropical, occurring in nearly all tropical and subtropical fresh waterways.

Water lettuce forms rosettes of wavy leaves.

It was first noted in Florida in 1765, and could have been there naturally but could also have been introduced there from elsewhere in the ballast water of earlier explorers’ ships. It is now present in the southeast U.S. north to New Jersey and New York, and westward to Texas, Arizona and California, as well as in Hawaii and Puerto Rico.

Water lettuce is a tropical aquatic plant, thriving in warm water (72-86F) and only growing when the water temperature is above 60F. It is extremely frost-sensitive and will not tolerate freezing temperatures*. It is very unique in appearance and not likely to be confused with any other aquatic plants.

This is an herbaceous perennial monocot with a rosette of overlapping, stemless leaves and long, trailing roots.

The leaves are densely covered with fine hairs.

The leaves are densely covered with fine hairs that prevent wetting of the actual leaf surface and trap air so the plant has increased buoyancy to float easily. The thick, velvety soft, cuneate leaves are up to 6 inches in length. They are a dull light green color with parallel ridges (veins), wavy margins and a scalloped distal end. The numerous roots that dangle from the rosette are multiply branched so appear feathery under water. The roots are light-colored at first, then change to a dark purple to black color, and make a great refuge for small fish. They can hang down up to a foot below the floating rosettes.

Feathery roots hang down from the base of the floating plants.

Water lettuce reproduces vegetatively by producing new rosettes on the ends of stolons.

The plant reproduces vegetatively by stolons, each of which grows another rosette, with the daughter plants remaining connected to the mother plant. Under ideal conditions numerous stolons and new rosettes are formed, allowing the colony to grow quickly to cover the water surface.

The tiny axillary flowers are very inconspicuous, nearly hidden at the base of the leaves in the middle of the plant.

The inconspicuous flowers are borne at the base of the rosette.

Each inflorescence is on a small stalk with a single female flower below and a whorl of male flowers above. A ½ inch, hairy, creamy white to pale green spathe encloses a single flower. Female flowers are sometimes followed by a small green berry. Although water lettuce can reproduce by seed, this is not a main means of propagation, especially when grown as an ornamental.

Water lettuce covering a small pond in eastern Brazil.

This floater occurs in ponds, lakes, and slow-moving rivers, forming large, dense masses. It is considered an aquatic weed worldwide; it is included on the Federal Noxious Weed List, and is illegal to sell or transport in some southern states. In Wisconsin it is listed as “caution” (although proposed to be changed to “prohibited”)*. Where prevalent, it can impede boating and fishing and adversely impact native flora and fauna – native submerged plants can be shaded out as the mat of leaves blocks light penetrating the water and fish may be killed from reduced oxygen in the water. In places where water lettuce is invasive, mechanical and biological controls are used to reduce populations. A leaf-feeding weevil from South America (Neohydronomous affinis) and a caterpillar from Thailand (Spodoptera pectinicornis) are being used for management of this pest in some places.

Water lettuce in a water garden.

Although this plant is of concern in some places, it can be used as an ornamental in controlled situations where it cannot escape. It is a popular addition to container water gardens and is sometimes used in tropical aquariums where it provides cover for small fish and removes nutrients in the water to prevent algal blooms. However, even in climates where it will be killed over the winter by cold temperatures*, it should not be used in open waterways as seasonal infestations have the potential to negatively impact the native environment. In small, isolated ponds the plants will help reduce build up of algae, but some of the plants may need to be removed periodically to keep them from overspreading the entire water surface and smothering other plants. The potential for flooding to cause even small ponds to overflow and allow for escape should be considered.

Water lettuce thrives in full sun in the Midwest, but does best with some midday shade in warmer climates. Combine water lettuce in container water gardens with miniature water lilies and emergent plants such as canna lilies, fiber optic grass, or corkscrew rush (Juncus effusus ‘Spirailis’). Or combine it with other floaters that don’t need to be rooted in a planter, such as water snowflake (Nymphoides indica), floating sensitive plant (Neptunia oleracea), or floating fern (Salvinia minima, another species proposed as “caution”) for an interesting contrast of shapes and sizes of foliage. As a tropical plant it should be placed on the water surface of outdoor containers or ponds after last frost. Remove small offsets to encourage more growth, or remove larger plants to slow reproduction.

Water lettuce overwintering in a fish bowl.

This plant is difficult to overwinter in cold climates, so most people let it die out and purchase replacements the following season. But if you wish to try to save plants for the following season, they should be moved indoors when nighttime temperatures are in the low 40’s. Supposedly plants can be overwintered on damp sand or peat. I have had success holding plants in a clear plastic goldfish bowl filled with rainwater (or snow melted and warmed to room temperature if my supply of stored rainwater runs out) kept in very bright light (a southern exposure or a greenhouse) and temperatures of at least 50F. Other plants kept in a mixed container in a greenhouse, where the other vegetation created some shade, have not fared as well, and the water lettuce there generally declines and disappears by mid-winter. Even in the fish bowl the plants languish over the winter, but with the arrival of longer days and warmer temperatures they begin growing again enough to restock my small water container garden in early summer.

*Because of recent reports of its apparent ability to overwinter even in cold climates, it is now recommended to be listed as PROHIBITED in Wisconsin so this plant should NOT be used in any situations other than container water gardens. If it does become prohibited, it will not be allowed to be bought, sold or used at all.

Update in 2015: Water lettuce is now listed as prohibited in Wisconsin’s invasive species rule (Wis. Adm. Code ch. NR 40).

– Susan Mahr, University of Wisconsin – Madison

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Q-Do you know anything about a plant called water lettuce? Is it edible?

A-Please don`t eat the water ”lettuce.” It belongs to the philodendron, or aroid, family, along with dieffenbachia, which is called dumbcane with reference to plant juices that can have a disastrous or deadly effect when chewed. The botanical name is Pistia stratiotes, and though it has clogged waterways and ponds in warm parts of America and isn`t allowed to cross some state lines, this aquatic makes an excellent houseplant to float in any tank or deep ceramic container. I have seen it grown well near sunny windows as well as in fluorescent-light gardens.

If you haven`t seen it, water lettuce looks a little like a beautiful head of real Boston lettuce floating on water. The leaves are quite different, with strongly vertical veins running parallel, and they are flattened rather than crinkled. But they are perfectly symmetrical rosettes, and the color is the encouraging green of new growth in general.

I am not sure where one obtains water lettuce but presumably from a local supplier of aquatics, such as water lilies and lotus. I hope many of my readers are cultivating water gardens; these plants help keep water healthy. Cattails, for instance, help clean up heavy-metals pollution from the water in which they grow.

During most of my half-century of gardening, there have been perhaps half a dozen suppliers of water plants in North America. Now there are many more. Already in England the plants and supplies for water gardening are offered at every garden center; it`s bound to happen here too.

If you have a friend who has some water lettuce, ask for a start. The plant moves along by means of stolons, like a strawberry or spider plant, and each of these comes amply supplied with roots. Of course, if your friend`s body of water is overrun with water lettuce, this person will think you ought to have a head check. Pistia is a tropical, so this means if frost occurs in your garden, weediness is of no concern.

Q-I have some dendrobium nobile orchids that have finished blooming. Should I cut out the canes that have already bloomed?

A-Presuming the canes that have finished blooming are healthy, leave them. Like the backbulbs in other orchids, they are needed to boost growth of the next generation. I usually cut them out the next year following bloom production, so in spring at repotting time mostly what remains are canes as old as 2 years and those sprouts or eyes that shoot up this year but which won`t bloom for another 18 months or so.-

Elvin McDonald cannot answer all questions individually, but he will respond to questions of general interest in this column. Write to him c/o The Chicago Tribune, Room 400, 435 N. Michigan Ave., Chicago, Ill. 60611.

Water lettuce growing leaf plant of the genus Pistia also known as Pistia stratiotes, Water lettuce perennial evergreen or annual used as ornamental plant also edible, can grow in mediterranean, desert, subtropics, temperate, tropics climate and growing in hardiness zone 4+.

Water lettuce leaves

Leaves color green 5-30 cm elliptic with wavy structure the leaves grow in rosette

Flower white and small grow in the middle of the plant the flowers hidden

Water lettuce for sale – Seeds or Plants to Buy

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Water lettuce plantsGrowing Water lettuce plantsWater lettuce plant care

How to grow Water lettuce growing and care:

Wetland, rich nutrient water

What is the best way to start growing?
Plant / Vegetative reproduction

Is it necessary to use vegetative reproduction?

Difficulties or problems when growing:
Aggressive, invasive

Planting season:
In hot climate all year in colder area spring

Pests and diseases:

Pruning season:
All year

How to prune:
Collect the dead part

Size of the plant?
2-20cm, 1-8 inches

Growth speed in optimal condition:
Fast growing

Water requirement:
Big amount of water

Light conditions in optimal condition for growing:
Full Sun / Half Shade

Is it possible to grow as houseplant?

Growing is also possible in a planter /flowerpot / containers:
Yes (with water)

Blooming information

Bloom season:

General information about the flower
Small White flower that grows hidden in the middle of the plant

Scientific name:

Pistia stratiotes

Blooming Seasons

  • Summer flowers

Flower Colors

  • White flower


  • Desert Climate
  • Mediterranean Climate
  • Subtropics Climate
  • Temperate Climate
  • Tropics Climate

Ornamental parts

  • Ornamental leaves
  • Ornamental plant

Plant growing speed

  • Fast growing plants

Plant life-form

  • Annual plant
  • Evergreen
  • Leaf plant
  • Perennial plant

Plant uses

  • Edible plants
  • Ornamental plants
  • Water plants

Planting season

  • Autumn Planting
  • Spring Planting
  • Summer planting
  • Winter planting

Plants sun exposure

  • Full sun Plants
  • Part shade Plants

Watering plants

  • Big amount of water

Hardiness zone

  • Hardiness zone 10
  • Hardiness zone 11
  • Hardiness zone 12
  • Hardiness zone 13
  • Hardiness zone 4
  • Hardiness zone 5
  • Hardiness zone 6
  • Hardiness zone 7
  • Hardiness zone 8
  • Hardiness zone 9

Lettuce Explain Bolting

Posted on May 29, 2018 in Fearless Food | 0 comments

Are your lettuce plants suddenly very tall? They may be bolting! This is when they send up a long flower stalk to begin the next stage of their lives – seed production! At this point, the leaves will be a little less sweet or even bitter, but you can still pick them off the flower stalk to eat.

You can pull the plant out now and re-seed more lettuce or plant something else. If you want to collect seeds from your own plant, leave it in the ground and let the flowers bloom. The seeds will be ready to harvest in 6-8 weeks.

Why does this happen? Bolting happens when the lettuce shifts from the vegetative state (growing a leafy head) to a reproductive state (growing flower stalks to produce seed). The bitterness comes from a sticky white latex, produced when the plant begins to bolt to protect against chewing insects during a vulnerable time in its life cycle – seed production.

Bolting is a natural part of the life cycle. While you can delay it from happening (essentially by keeping the plant in the vegetative state for as long as possible), it is inevitably going to happen.

You can keep it in the vegetative state a little longer by:
-planting varieties that are “slow bolting”
-harvest older, outer leaves first and often for looseleaf varieties, or cut 2/3 of the plant (from the top) every week or two for heading varieties
-keep cool (shade is great) and water well
-snip off the flower stalk as soon as it appears

You can also just plan for bolting to happen in your garden, and plant succession crops of lettuce every 3-4 weeks. That way, you’ll have tender, sweet lettuce all season long.

Lettuce Propagation Methods

Locally sourced salads have become trendy these days and for good reason! Nothing beats freshly picked lettuce to add to your dishes. Luckily, it’s not a difficult thing to grow yourself—and the results are well worth it. Here are some tips on lettuce propagation methods.

Choose Your Favorite Type of Lettuce

Many of us eat only a few kinds of lettuce because of what’s normally at the grocery store (iceberg, romaine, leaf), but there are hundreds to choose from: radicchio, purslane, arugula, oak leaf, butter lettuce, etc. Don’t feel you have to limit yourself, but at the same time keeping it simple (especially if you are just getting into it) is okay, too.

Preparing Lettuce Seeds

Lettuce grows best in spring or fall when the weather is cool, but their seeds will only germinate in warm conditions around 70 F with lots of light. Cover seeds lightly with soil and keep them moist (not drowning) until a few leaves develop. Once they’ve sprouted, take them out of the heat, otherwise the plants will bolt to flower and the leaves will taste bitter.

Preparing the Ground

Soil should be kept moist with good drainage whether in planters, pots, or in the garden. Choose a cool spot in either sun or shade and give each variety enough space to grow. Companion planting is a great idea: choose tall veggies like tomatoes or herbs that will shade lettuce and keep them cooler over the season. Create your own ready-to-go “salad pots” by placing your lettuce with another veggie and herb all in one planter and let them grow together for easy picking throughout the season.

Picking Lettuce Leaves

For the majority of lettuce varieties except head lettuce, picking full grown leaves is the best way to help the plant to continue to propagate, as energy is re-directed to new center growth. Use garden sheers, scissors, or simply rip carefully with your hands so that the leaf is picked leaving a half inch of the stalk left. Do not pick more than half the plant at one time to promote healthy regrowth.

Trimming Methods

For “loose-leaf” varieties, you can also trim your lettuce completely once it has established full growth to help it reproduce. Cut off all leaves with scissors or a knife keeping around 2 inches of the bottom of the plant intact. This is especially good to do if you noticed the plant has gone to seed or has started to bolt. Cutting it back resets its internal clock, and while leaves won’t be as large as the original harvest you can get an extra round by doing this.

Romaine Cut-offs

Similar to trimming methods in the dirt, romaine lettuce will grow new leaves from the main cut you usually throw into the garbage (or compost) in your house. Place the nub into a bowl filled with a few inches of water and put it on a windowsill or table. New leaves will culminate in about 10 days—enough to top sandwiches or make a small salad. Some may not produce anything but it’s a neat indoor method to propagate this variety—and there’s nothing to lose!

For hefty harvests, plant succession crops so that these methods of picking, trimming, and cutting will continually provide fresh lettuce all season. Small crops of one or two plants can be just as fun to grow—and eat! Either way, with these tips, there’s no reason you can’t get your greens. sativa (lettuce)

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Lactuca sativa, lettuce

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cellular organisms – Eukaryota – Viridiplantae – Streptophyta – Streptophytina – Embryophyta – Tracheophyta – Euphyllophyta – Spermatophyta – Magnoliophyta – eudicotyledons – core eudicotyledons – asterids – campanulids – Asterales – Asteraceae – Cichorioideae – Cichorieae – Lactuca – Lactuca sativa

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Brief facts

  • Lettuce is an annual or biennial plant most often grown as a leaf vegetable. It was cultivated from the time of Egyptian Pharaohs and, presently, is one of the most important leafy crops worldwide.
  • Lettuce leaves contain small amounts of opiate-like substance, lactucarium (“lettuce opium”), which is a mild sedative. Our ancestors used lettuce to treat anxiety, insomnia, and neurosis. Lettuce is rich source of antioxidants such as quercetin, caffeic acid, vitamins A and C. It was shown that ethanol extract of lettuce injected subcutaneously, significantly decreased accumulation of lipofuscin pigment granules (“age granules”) in brain of mice under accelerated ageing regimen (the mice were administered D-galactose).
  • Lettuce originates from the wild Lactuca serriola found in the Mediterranean and Near East and has been transformed from an erect plant with bitter leaves to various cultivars including ones with distinctive heads of chlorophyll deficient leaves. Other wild relatives of genus Lactuca (L. aculeata, L. scarioloides, L. azerbaijanica, L. saligna and others) also most likely contributed to the cultivated lettuce gene pool. Usually, the wild species lanraces are only partially cross-fertile with L. sativa. Occasional inter-species hybrids are used to introduce disease resistance genes into garden lettuce’s stock.

Morphological types of L. sativa (Lebeda et al. (2007))

  1. Butterhead lettuce: loose head with soft and tender leaves, eaten raw; very popular in Europe and USA.
  2. Crisphead lettuce: heading type with thick crisp leaves and fan-like (flabellate) leaf venation, eaten raw.
  3. Cos lettuce (named after Greek island Cos): tall loose heads; oblong rigid leaves with a prominent midrib; eaten raw or cooked. Often, Cos lettuce cultivars are sold as “Romaine lettuce”.
  4. Cutting lettuce (Gathering lettuce, Loose-leaf, Picking lettuce, Schnittsalad): non-heading type, harvested as whole, as open rosettes, and, occasionally as separate leaves; eaten raw. Cultivars vary widely in leave shape and coloration – from flat to curled, from smooth-edged to fringed, from plain green to decoratated with patterns of various intensities of anthocyanin pigmentation.
  5. Stalk (Asparagus) lettuce: plants with swollen stalks, which are eaten raw or cooked like asparagus; very popular in China and India.
  6. Latin lettuce: loose heads with dark green thick leathery leaves; eaten raw; mainly cultivated in the Mediterranean countries, including North Africa.
  7. Oilseed lettuce: characterized by a high percentage (35%) of oil in the seeds, which is used for cooking; in Egypt, cultivation of oil-seed lettuce has continued to the present time.

Most important lettuce diseases

  • Lettuce mosaic virus (LMV)
  • Lettuce downy mildew (Bremia lactucae)
  • Lettuce drop (Sclerotinia spp.)
  • Lettuce shot hole or ring spot (Microdochium panattonianum)
  • Bottom rot (Rhizoctonia solani)
  • Pythium wilt (Pythium spp.)
  • Botrytis blight or gray mold (Botrytis cinerea)
  • Lettuce powdery mildew (Golovinomyces cichoracearum)
  • Septoria leaf spot (Septoria spp.)
  • Aphids: Green Peach Aphid (Myzus persicae), Lettuce Aphid (Nasonovia ribisnigri), and Lettuce Root Aphid (Pemphigus bursarius).

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Developmental stages (life cycle)

  • Seed stage MeSH
    • Dormant seed
    • Germinating
      seed MeSH The germinating seedling may take up to 5 days to emerge.
  • Vegetative
    • Seedling MeSH Young plant (1-2 weeks). Soaking seeds or seedlings in ethanol and methanol solutions have been reported to stimulate germination and biomass accumulation in some plant species. It was shown that lettuce 2-true-leaves stage seedlings dipped in 10-15% ethanol solution for 2 minutes produced ~20% more biomass than not dipped seedlings.
    • Head formation Corresponds to rosette stage in other plants; when head is fully formed and grown, plant considered to reach vegetative maturity and ready for harvest (from 45 days after emergence for Prizehead lettuce to up to 90 days for Salinas lettuce); loose-leaved varieties are harvestable sooner than tight-head varieties. Exposure to lower night temperatures increases leaf flesh biomass and dry weight per unit of leaf area by facilitating leaf thickening and spongy layer development.
    • Bolting Further vegetative growth and rapid growth of stem; this period lasts approximately another 30 days; the lettuce is harvested before it bolts.
  • Reproductive
    • Flowering Approximately 2-3 months after emergence; when lettuce blooms its stem lengthens and branches, and it produces many flower heads that look like those of dandelions, but smaller. Flowering plant can reach height of up to 1 meter. Flowering continues for 3-4 weeks. Flowers usually open in the morning and close in the evening.
    • Ripening Seed ripening starts in 11-13 days after opening of the flower head.

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Lettuce seeds were sowed on April 25th, 2010.

Young lettuce plant, 40 days after sowing. Lettuce began to bolt in about 2 months after sowing.

Two different lettuce cultivars continue bolting 2.5 months after sowing.

Young inflorescence with flower buds 3 months after sowing. Lettuce plant flowering. Flowers open gradually as the inflorescence grows.

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Lettuce growing at George Washington’s Mount Vernon garden

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Appendix I: lettuce die-back disease

Simko I, Pechenick DA, McHale LK, Truco MJ, Ochoa OE, Michelmore RW, Scheffler BE.
Association mapping and marker-assisted selection of the lettuce dieback resistance gene Tvr1. BMC Plant Biol. 2009 Nov 23;9:135.

Lettuce dieback disease is widespread in commercially grown romaine and leaf-type lettuces. The disease is caused by two closely related soilborne viruses from the family Tombusviridae – Tomato bushy stunt virus (TBSV) and Lettuce necrotic stunt virus (LNSV). Symptoms of lettuce dieback include mottling and necrosis of older leaves, stunting, and plant death.

Dieback symptoms on different types of lettuce:
A – stem type, B – leaf type, C – green romaine, and D – red romaine.
Plants on the left are healthy, while plants on the right show typical symptoms of dieback, such as stunted growth, yellowing of older leaves, and gradual dying. Photographs were taken eight weeks after planting.

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  • Wikipedia: Lettuce
  • Lactuca sativa (garden lettuce) | USDA PLANTS

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Last updated 05/18/13
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Water lettuce (Pistia stratiotes) are floating aquatic plans grown for their chartreuse green foliage arranged in compact rosettes. Called Nile Cabbage, they belong to the Arum family and consist of a single species. Although originally from Africa, water lettuce is now found in most freshwater bodies in tropical and subtropical areas.


Leaves are thick and hairy with parallel veins and scalloped edges. They have no stalks and seem to arise directly from the roots as the stem is highly reduced. The feathery roots grow up to a foot underwater, but the rosettes remain less than six inches in height, forming a low mat over the water surface.

Zone Compatibility

Water lettuce flourish in USDA zones 9 – 11. They can be grown in colder climates with adequate protection. The ideal temperature range is 70 – 85 F, but they can survive in temperatures down to 50 F.

Procuring Plants

They are usually available in garden centers and shops selling aquarium plants. When purchased by mail order, they may not look their best initially. Allow them to recuperate in a small pot in a shady place before adding them to larger arrangements or fish ponds.

A few varieties with slight difference in leaf shapes are available, but they all belong to the single species Pistia stratiotes.

  • Ruffles has slightly ruffled leaves as the name implies.
  • Jurassic can grow very large rosettes but growth is slower.
  • Splash has variegated leaves, but is rarer than other varieties.


Pistia self-propagate prolifically by making baby plants on the tip of stolons arising from almost every leaf axil. The tiny white flowers arising from the axils of leaves at the center of the rosette have a single bract like the other plants in the Arum family. Each fertilized flower grows into a single berry, but is not usually used for making new plants in cultivation.

Culture and Maintenance

  • Pistia can be grown in small pots by itself or as part of an assortment of other aquatic plants in larger tubs. They prefer quiet waters and overcrowding; adding a floating ring will keep them together and happy in agitated ponds.
  • They do better in shade, but too little light will make the leaves turn a darker green. In a very sunny location they may have a bleached look.
  • As tropical plants, they need warmth to grow well. Cold winters will kill them. However, they are easily kept indoors near a bright window until warm weather returns. They can be overwintered by planting them in pots filled to the rim with water too.
  • Bottom soil is not necessary for growth, but they require periodic fertilizing to thrive. In the absence of adequate nutrition, many plantlets are produced, but the rosettes remain small. Place them occasionally in a small vessel containing Miracle-Gro to give them a boost. Adding a little potassium nitrate to the water is another option.
  • They do well in koi and goldfish ponds, using up their nitrogenous wastes, but may need to be grown in net baskets if the fish population is too high.


  • Water lettuce adds interesting color and texture to mixed groupings in tubs and ponds.
  • They can be used in fish ponds as they provide food and shelter. The hanging roots offer protection to spawn and smaller fish.
  • They play a role in preventing algal blooms by using up nutrients in the water.
  • Water lettuce is not related to the lettuce used in salads. Young leaves are edible when cooked, but not highly recommended. Bruised fresh leaves can cause itching because of the calcium oxalate crystals present.


  • Yellowing of leaves may result from nutritional deficiency and too much sun exposure.
  • Some water snails and fish feast on the roots and leaves, destroying the plants completely.
  • Their hairy leaves have water repellant capacity, but constant splashing from fountains and waterfalls cause rotting.
  • They provide a haven for mosquito larvae; Mansonia mosquitoes are specially adapted for living in the root system of water lettuce.
  • When allowed to grow unchecked, Pistia can crowd out other aquatic plants. The submerged oxygenator plants in the pond may die off from lack of sunlight, and animal life dependent on them may follow suit.
  • Their prolific growth can choke waterways and destabilize natural ecosystems and destroy native plants and animals.

Easy to Grow

Water lettuce is easy to grow and an interesting addition to any garden, but the growth should be kept in check by removing excess plants. Never dispose of them in natural water bodies.

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