Winter is hard on your flowers. Tender annual flowers like impatiens can’t survive a frost or temperatures below 55 degrees. Half-hardy annual flowers can survive brief, light frosts and temperatures of 35 degrees to 45 degrees. To be safe, protect all your plants when the temperatures drop.
If the forecast calls for a cold front or frost, use the methods below to cover your flowers.
- How Much Cold Can a Christmas Cactus Take?
- Spring and Summer Temperatures
- Fall Temperatures
- Forcing Flowering
- Temperature Problems
- Cacti and Other Succulents
- Christmas Cactus Cold Tolerance – How Cold Can Christmas Cactus Get
- Christmas Cactus Cold Hardiness
- How Cold Can Christmas Cactus Get?
- Treating Christmas Cactus Exposed to Cold
- Christmas Cactus Overview
- Types of Christmas Cactus
- Christmas Cactus Care
- Caring for Christmas cactus
How to Cover and Protect Flowers from Frost and Cold Nights:
- Water the area surrounding your plants the night before a frost to protect them from freezing. Wet soil releases moisture in the air, which raises the temperature and keeps plants warmer throughout the night.
- Choose a cover:
- Use old sheets, drop cloths, tarps, burlap or newspapers.
- If you have cardboard boxes, open them on one end, turn them upside down and place them over your flowers. Tape any cracks to keep out the cold air.
- Use empty pots, buckets, milk jugs with the top cut off, or other containers made of wood, plastic or clay to cover your plants. Be sure they’re tall enough to fit over plants without crushing them. If there are drainage holes in the pots, put rocks or pieces of broken pots over them.
- Cover your flowers with sheets of plastic. Don’t use thin plastic bags, which can freeze your plants.
- Use pre-made row covers to shield your plants from frost. Some are made of breathable materials, so you don’t have to take them off in the morning and put them back on at night.
- Place covers over your plants before the temperatures hit freezing. If you’re using plastic covers, wait until twilight to avoid the sun cooking your plants through the plastic.
- If your cover is lightweight enough to blow away in the wind, weigh it down with rocks or bricks.
- Remove cardboard or fabric covers as soon as the weather warms up. Remove plastic covers as soon as the sun rises.
- Watering can or hose
- Plastic sheeting
- Pre-made row covers
- Tarp or drop cloth
- Optional: Rocks or bricks
How Much Cold Can a Christmas Cactus Take?
Christmas cactus (Schlumbergera bridgesii) produces red, pink, lavender or peach blooms during the winter months when the temperatures are right for healthy growth. This tropical cactus can only grow oudtoors in U.S. Department of Agriculture plant hardiness zones 11 and 12, so it’s most often grown as a houseplant. Although it can’t tolerate cold, it performs best in the winter in cooler temperatures.
Spring and Summer Temperatures
Christmas cactus requires moderately warm temperatures during its active growing season, which lasts from spring, after flowering is complete, until late summer when the plant begins to prepare for the next flowering season. Maintain temperatures between 70 and 80 degrees Fahrenheit. Although you can place the plant outside during the summer, avoid setting it out if temperatures are below 50 F. Place the cactus in an area with bright but indirect sunlight, because direct light can scorch the plant.
Although the Christmas cactus responds better to lower temperatures in fall when it’s beginning to set flower buds, it still cannot tolerate temperatures lower than 50 F. Buds won’t form if the temperature is too high or if the plant receives too much light. Maintaining temperatures between 60 and 68 F while providing 14 hours of complete darkness every night for six weeks, beginning in mid-September, help ensure the maximum amount of flowers during the winter blooming season. Maintain the lower temperatures through winter to help the flowers persist as long as possible.
If absolute darkness each evening isn’t possible, you can use lower temperatures to force bud formation. Provide the cactus with as much darkness as possible, but keep it in a continuously cool spot. The cactus will form flower buds if temperatures remain between 50 and 59 F, but avoid lower temperatures as these may damage or kill the cactus. The cactus may not form as many buds with this method as with controlled hours of darkness.
Temperatures above 90 F can harm Christmas cactus, especially when flower buds are forming. The buds drop off in high temperatures, so avoid placing the cactus in overly warm, sunny spots or near heat vents. Temperatures below 50 F also cause bud drop and slow down the cactus growth. Prolonged periods of less than 50 F may eventually damage or kill the plant. Freezing temperatures will usually kill a Christmas cactus.
Cacti and Other Succulents
CACTI are some of the most rewarding house plants, as long as you have adequate light. Few flowers can compare in color, size or beauty. Most cacti grow slowly, so space is usually not a problem. They are very tough and adaptable. Contrary to popular belief, they do not “thrive on neglect”. Like most plants, they “thrive” on tender loving care, but they will at least “survive” on neglect.
The general care information below is for cacti and most other succulent plants. *Exceptions include epiphytic (tree-dwelling) cacti and succulents—Christmas cactus, rhipsalis, orchid cacti, etc.—which prefer less sunlight, more humidity, and more watering than other species. They also appreciate a higher percentage of nitrogen in their fertilizer. Add less sand to your potting mix than for other species. Haworthias and some other succulents also prefer bright indirect light to direct sun.
Indoors, give cacti and other succulents the brightest or sunniest window you can provide (four to six hours of direct sun). In less light, they will become long and skinny, an abnormal growth habit. We highly recommend summering your plants outdoors in morning or late afternoon sun, where increased air circulation and light will benefit them immeasurably. Most succulents can endure full outdoor sun, but must be acclimated to it. When placing plants outside, first set them in partial shade or shade, gradually introducing them to the strong late spring and summer sun over a couple of weeks.
Wooly and heavily spiny species require the most sun, while spineless species normally require midday shade. A reddish discoloration may indicate that your plant is at or beyond the intensity of sun it can tolerate.
When you water, water thoroughly, and allow the soil to dry before watering again. Succulents are especially prone to rot as a result of over-watering. NEVER water your plant if the soil is already moist. Dry pots are lighter than wet ones. Clay pots feel cool and damp to the touch when soil is moist within them. Succulent leaves are firm and plump when the plant has enough moisture in the soil.
Most cacti and certain other succulents prefer to remain considerably drier in the cooler seasons of the year (usually October through April). Water less frequently than normal during this period. In the spring, you may mist your plants early in the morning on warm days, to stimulate new growth. Plants will absorb moisture through their spines. We also recommend watering plants from the bottom of the pot during early spring, so that new roots may develop free from the suffocating effect of overly wet soil. Fill the plant’s saucer with water, and allow about 30 minutes for soil, pot and plant to draw up moisture, then discard the excess water.
If your plants are in clay pots, they will achieve maximum potential if you embed them in a mixture of 50% peat and 50% coarse builder’s sand. This prevents rapid drying of the soil, and allows the roots to develop in the even moisture created by the peat/sand mixture. Be sure the tray holding the peat/sand mix has good drainage.
In winter, keep cacti and succulents above freezing. Some plants prefer a nighttime temperature of 35-40ºF (some cacti and other succulents can endure temperatures well below freezing if kept absolutely dry.) More tropical succulents like adeniums, euphorbias, lithops, and stapeliads prefer a minimum of 50-60 degrees.
In summer, plants should be protected from extreme heat, as their root systems are more vulnerable to damage in a pot. When humid and hot, good air circulation and careful watering will avoid fungal and rot problems.
Feed your plants once a month from May to September with a low nitrogen (less than 10%) formula fertilizer such as 5-10-5 or 10-30-20. Too much nitrogen encourages excessive rapid green, but weak growth. Always dilute the fertilizer more than the label instructions advise, as most cacti have adapted to growing in nutrient-poor soils.
Repot in the spring or early summer. Most species appreciate annual repotting when young, only increasing one pot size. Once you reach about a 6” pot size, you may carefully remove the top inch or two of soil, and replenish this with fresh mix, without moving the plant to a larger pot. Succulents tend to be heavy plants, especially potted in clay, and become difficult to handle when moved to larger and larger containers.
Avoid soils with a high percentage of peat moss. Peat holds water too long, and will not moisten easily once allowed to dry completely (a frequent occurrence with most succulents). A small amount of peat can be used to improve soil texture, and you may add coarse builder’s sand to the soil to increase drainage. Lithops (living stones), wooly cacti and stapeliads appreciate as much as 40% sand. A top dressing of fine gravel around the base of the plant is advisable as it promotes better absorption of water into the soil, protects the plant base from excessive moisture, and is esthetically pleasing as well. If possible, add a tablespoon of bone meal and gypsum for every 3
inches of pot size.
For heavily spiny plants, use a pair of wooden tongs or a rolled up piece of newspaper to grasp the plant and ease it out of its pot. If stubborn, do not force the plant out, as you will damage the root system. Tap the pot against a hard surface and try again. Remove as much soil as possible without damaging the root ball. Always repot the plant at or above the previous soil level, to discourage rot. You may need to stake columnar species. Wait a week or two after repotting before watering to allow new root hairs to develop.
By Albert Mondor, horticulturist and biologist
Perennial cactuses that withstand our harsh winters? Yes, they exist! Of the four cactus species that grow in the wild in Canada, the brittle prickly-pear cactus (Opuntia fragilis) is assuredly the hardiest, contrary to what its name suggests. Indeed, it grows at 58º North latitude in Alberta, that is, less than 8º from the Arctic circle!
Scientists have determined that in its natural environment, Opuntia fragilis withstands temperatures around – 50 °C. Furthermore, they subjected the cactus to a temperature of −70 °C and immersed it in liquid nitrogen at −196 °C following slow freezing down to −40 °C. Well, after that extreme treatment, 50% of the stems survived! Unbelievable but true! For their part, the eastern prickly-pear cactus (O. humifusa) and escobaria (Escobaria vivipara), two other species of cactuses indigenous to Canada, survive at temperatures surrounding –35 °C.
Sold in some Canadian garden centres and nurseries, the cactuses described above can be grown outdoors in a flower bed, along with tropical perennials and annuals. With soil that drains well, such as the PRO-MIX® Cactus Mix, and a sunny location, those plants will grow easily without requiring any special care. Just let the sun and rain do their job!
(Escobaria vivipara) (Photo Credit: Stan Shebs)
Height: 5 cm
Width: 30 cm
Flowering: pink in July and August
Hardiness: zone 3b
Except its great resistance to cold temperatures, this spherical cactus is particularly beautiful at the beginning of summer with its large pink flowers.
Eastern prickly-pear cactus
Height: 20 cm
Width: 90 cm
Flowering: yellow in July and August
Hardiness: zone 3b
The eastern prickly-pear is a perfectly hardy cactus in our climate. In fact, if it’s covered with snow in the winter, this beautiful yellow-flowered plant quite easily withstands temperatures around – 35 °C. However, come spring, its stems are brown and shrivelled up. Generally, a few weeks are needed for the cactus to go back to its normal coloration and appearance.
Brittle prickly-pear cactus
(Opuntia fragilis) (Photo Credit: Dornenwolf)
Height: 10 cm
Width: 90 cm
Flowering: yellow in July and August
Hardiness: zone 1
The brittle prickly-pear is most certainly the most resistant to cold temperatures! It is quite unusual for an opuntia as it produces spherical stems rather than flattened stems like most of the other species. Over time, its stems form a thick carpet and bear pretty yellow flowers in the summer.
Christmas Cactus Cold Tolerance – How Cold Can Christmas Cactus Get
When you think of cactus, you probably envision a desert with heat wavering vistas and blazing sun. You aren’t too far off the mark with most cacti but the holiday cacti actually flower better in slightly cooler temperatures. They are tropical plants that need slightly cooler temperature to set buds but that doesn’t mean that Christmas cactus cold tolerance is high. Christmas cactus cold damage is common in cold drafty homes.
Christmas Cactus Cold Hardiness
Holiday cacti are popular houseplants that bloom around the holiday in their name. Christmas cacti tend to flower around the winter months and produce bright bountiful pink blooms. As exterior plants, they are only hardy in United States Department of Agriculture zones 9 to 11. How cold can Christmas cactus get? Cold hardiness in Christmas cactus is greater than some cacti, but they are tropical. They can’t tolerate frost but they need cold temperatures to force blooms.
As a tropical plant, Christmas cacti like warm, balmy temperatures; moderate to low moisture levels; and bright sun. It likes to be warm but keep the plant away from extremes such as drafts, heaters and fireplaces. Perfect nighttime temperatures range from 60 to 65 degrees Fahrenheit (15-18 C.).
To force bloom, place the cactus in a cooler area in October where temperatures are about 50 degrees Fahrenheit (10 C.). Once the plants are in bloom, avoid sudden temperature fluctuations which can make Christmas cacti lose their flowers.
In summer, it is completely fine to take the plant outdoors, somewhere with dappled light initially and shelter from any wind. If you leave it outside too far into fall, you can expect Christmas cactus cold damage.
How Cold Can Christmas Cactus Get?
To answer the question, we need to consider the growing zone. The United States Department of Agriculture provides hardiness zones for plants. Each hardiness zone illustrates the average annual minimum winter temperature. Each zone is 10 degrees Fahrenheit (-12 C). Zone 9 is 20-25 degrees Fahrenheit (-6 to -3 C) and zone 11 is 45 to 50 (7-10 C).
So as you can see, the cold hardiness in Christmas cactus is fairly broad. That being said, frost or snow is a definite no-no for the plant. If it is exposed to freezing temperatures for more than a quick nip, you can expect the pads will be damaged.
Treating Christmas Cactus Exposed to Cold
If the cactus is out too long in freezing temperatures, the water stored in its tissues will freeze and expand. This damages the cells inside the pads and stems. Once the water thaws, the tissue contracts but it is damaged and doesn’t hold its shape. This results in limp stems, and eventually dropped leaves and rotten spots.
Treating Christmas cactus exposed to cold requires patience. First, remove any tissue that appears to be badly damaged or rotten. Keep the plant lightly watered, but not soggy, and place it in an area around 60 degrees F. (15 C), which is moderately warm but not hot.
If the plant survives six months, give it some houseplant fertilizer that has been diluted by half once per month during its growth months. If you put it outside the next summer, just remember Christmas cactus cold tolerance doesn’t extend to freezes, so get it inside when those conditions threaten.
Ah, Christmas. That beautiful time of year when everyone starts thinking about pine trees, poinsettias, and cacti, candy canes and…
Yes, my friend. Specifically, the Schlumbergera, otherwise known as the Christmas Cactus. It has been a cherished Christmas tradition for many families since the early 1800s.
If this is your first time hearing about them, you may jump at this chance to add a new tradition to your family’s holiday celebrations. As if you needed an excuse to add another plant to your collection, right?
Christmas Cactus Overview
A fantastic shot of blooming christmas cactus from Timothy over at Kicking Designs
|Common Name(s)||Christmas cactus|
|Height||Up to 2 feet|
|Water||Average, do not let it dry out|
|Fertilizer||Mild, every 2 weeks|
|Propagation||Cutting flowers only|
|Pests||Fungus gnats, flower thrips, and root mealybugs, spider mites.|
This succulent is native to south-east Brazil coastal mountains. Named the Schlumbergera after a Frenchman who collected cacti in the 1800s, this plant became tied to holidays through their colorful flowers. The christmas cactus bloom ranges from white to purple, depending on the type.
Types of Christmas Cactus
There are six species of this cacti, grouped into two categories: Truncata and Buckleyi.
The three commonly-known holiday cacti are named for when their blooms appear: Thanksgiving, Christmas, and Easter.
Christmas Cactus Care
Proper christmas cactus care may be a bit different from what you’d expect of the usual desert cacti, as these are tropical rainforest succulents. That being said, even the laziest gardener won’t be hassled with this easy-going greenery. Take special note of the following information on how to care for a christmas cactus.
This plant can survive ranges from 35 degrees to 100 degrees but the healthiest range lies between 65 and 80 degrees. Bring the little beauties inside if your outdoor temps go to the extremes.
Unlike their desert cousins, the Schlumbergera are not fond of too much direct sunlight. Bright, indirect light will do just fine for the best blooms, though they will tolerate low amounts of light as well.
Most of us think of cacti as being drought tolerant, which isn’t necessarily the case with this particular type. Though it does store a small amount of moisture in its leaves, it’s best to water when the first surface inch of soil is dry.
That may mean not keeping a regular watering schedule, thanks to variations in humidity and temperature, but checking regularly for soil dryness instead. Busy gardeners rejoice in having a plant that doesn’t need a constant showering of water!
Christmas cactus soil can be made yourself using one part sand and two parts potting soil or you can purchase mixes designed especially for succulents. As long as it is well-draining, of course, it doesn’t take much to have a happy cactus.
A fertilization plan of two to four times a year with high-quality 20-20-20 is all you need to feed these babies. As you get to know your plant’s blooming pattern, skip the fertilizer a month before buds make their presence known.
Often when an ornamental plant is purchased, it comes in a small pot and may outgrow the pot. If the reader needs to repot the plant, how would they do it?
Pruning after blooms have gone will encourage branching out of the stems. Simply remove a few sections with a sharp blade. What to do with those cut pieces? I’m getting to that next.
Christmas cactus propagation is easy peasy. While you’re going about pruning, you can propagate the cut sections by placing them in moist vermiculite to root into new plants. (See? I didn’t make you wait too long, did I?).
We’ve got an in-depth guide revealing how to propagate Christmas cactus. It’s worth the read!
If you want a little more control over your christmas cactus bloom timing, pay close attention to the amount of light and temperatures your area experiences. Shortening the amount of light during the day (allowing around 12 to 14 hours of complete darkness) and dropping the temps to about 50 degrees at night, along with less watering, will mimic the ideal conditions for blooming.
These cacti can have the occasional issue like any other plant. Here’s how to handle some of the common problems.
Limp or Wilted Leaves
Your watering habits may be to blame for this issue. Too much or too little watering can cause limp leaves. Being a native to tropical forests, it prefers to draw moisture from the air, not from the roots. Soggy roots make a sorry succulent in this case. Check for drainage backup as well.
Another solution may include repotting into a slightly larger container or even just a fresh batch of soil. Don’t go crazy and move the plant from an apartment-sized container to a mansion-sized container; though you may like thousands of square feet to wiggle your toes in, they prefer tighter living spaces.
If the above suggestions didn’t help with wilting issues, there may be a pest or disease involved. Check these out and see if they’re a match for your situation.
Spider Mites – Seeing some webbing on the leaves of your beloved plant? Spider mites are probably to blame. Try a little insecticidal soap. And as much as you may detest the chore, make sure you keep your plants’ home dusted. Spider mites love dusty places.
Fungus Gnats – These actually might be more annoying to you than to your plants. However, they can cause damage in large numbers. Make insecticidal soap your ally and avoid soggy soil. You may have to start over and repot into fresh mix and a clean container.
Scale – If you see a waxy substance on the leaves, you’ve probably got a case of scale. These little juice suckers can be scraped away if you catch it early, or you can use—did you guess?—a spritz of insecticidal soap.
Pythium and Phytophthora Root Rot – These parasites cause the plant to wilt and die. Choosing a pasteurized potting mix (to avoid bringing the little buggers home in a bag) and getting rid of other infected plants will help reduce the chances of them choking the holiday spirit right out of your green gifts.
Botrytis Blight – Unfortunately, much as our Christmas tropical succulent appreciates a little humidity, so does this fungus. You may see dead blooms with a grayish growth on them. Apply a little fungicide and control the amount of humidity through ventilation and temperature levels.
Impatiens Necrotic Spot Virus – The tricky part about this virus is that your plants may be carriers without any symptoms at all, a most frustrating nemesis. If you suspect any of your plants displaying odd signs of infection, better to toss them. Make sure to control your thrip population as well.
Basal Stem Rot – Just as it sounds, you’ll see a brown stain at the soil line, the sign of dying tissues. Avoid injuring plants in that area and use a bit of fungicide for protection.
Q. I’m having a hard time rooting my christmas cactus in water. What’s going wrong?
A. While you CAN root many plants in water, it’s not often recommended. Christmas cactus is one that prefers to be rooted in moist vermiculite or cactus mix. You will have a much higher success rate with this method.
Are you bored with the same old poinsettias and tiny pine trees bedecked with little ornaments you see in every store at Christmastime? Are you looking for a different gift for friends, family, and coworkers to go with that bottle of wine you bring to the party? (Conveniently forgetting that second bottle at home, of course.)
Consider the beautiful flowers and pleasing green stems of the Christmas Cactus. You just may start a new tradition or surprise someone with an old tradition they used to love.
Tell me your stories of this delightful plant in the comments, share this article with your friends if they are looking for new varieties to add to their greenhouse, and pepper me with any questions keeping you up at night. Thanks for stopping by!
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Caring for Christmas cactus
If you’re lucky, you could receive a Christmas cactus as a gift this holiday season. This common houseplant blooms during the Christmas season, but its long green arms are attractive throughout the year. With cultivars in a rainbow of colors, it is a plant worthy of appreciation. These 10 facts about Christmas cacti will help you to care for your plant if you happen to receive one this holiday season.
It’s called a “cactus,” but it thrives in cooler temperatures. Christmas cacti need to be kept away from heat sources. According to the Purdue University Extension Service, a Christmas cactus will blossom longer when exposed to only cooler temperatures. For best results, keep your Christmas cactus in a cool place (away from heaters and fireplaces) where there are not frequent drafts. Right next to a frequently used door would not be a good place. Big changes in temperature can cause the blooms to drop off the plant before they open. The optimal temperature for Christmas cacti is 68 degrees Fahrenheit.
Christmas cacti need light to bloom. According to the Purdue University Extension Service, keeping your Christmas cactus in a sunny location indoors is the key to prolonged blooms. However, if you move it outside during the summer, you’ll have the most success in a partially shaded location, because too much direct light can burn the leaves.
The Christmas cactus is native to Brazil. These epiphytes (a plant that grows on top of another plant nonparasitically) grow in the Brazilian rain forest, among tree branches, according to Clemson University Cooperative Extension. Since they are tropical plants, they thrive in humid conditions.
Christmas cacti need their beauty sleep. The horticulture experts at the Cheyenne Botanic Gardens recommend setting your Christmas cactus in a room where you never turn the lights on at night. In order for the flower buds to set, Christmas cacti need 14 hours or more of continuous darkness per day. However, after the flower buds have set, Christmas cacti can withstand lights on at night.
Unlike poinsettia, the other Christmas favorite, a Christmas cactus is not toxic to dogs and cats. Poinsettia is famously poisonous to dogs and cats. However, according to the ASPCA, if Fido or Fluffy nibbles on a Christmas cactus, she should not experience irritation or vomiting like she would from the sap of the poinsettia.
Christmas cacti can live for 20 to 30 years. Can you imagine passing a living, flowering plant on to your children or grandchildren? According to the Old Farmer’s Almanac, when properly cared for, Christmas cacti can live for 20 to 30 years. If you provide long nights starting around Oct. 1, you can force the Christmas cactus to bloom year after year. Cool night temperatures can also encourage it to bloom.
Overwatering will kill Christmas cacti, but they like to be misted daily. A horticulturist at the Oregon State University Extension Service recommends only adding water to the soil that a Christmas cactus is planted in when the soil is dry to the touch. Alternately, gardening expert and radio host Walter Reeves, the Georgia Gardener, suggests misting the leaves of the Christmas cactus to maintain the desired level of humidity around the plant.
Five diseases commonly infect Christmas cacti. Penn State University Extension experts provide a handy fact sheet that outlines the plant diseases that most often affect Christmas cacti. Their list includes: basal stem rot, botrytis blight, impatiens necrotic spot virus, phytophthora root rot and pythium root rot.
Fungus gnats, flower thrips and root mealybugs are the pests that most often infest Christmas cacti. The University of Massachusetts-Amherst Extension Service recommends preventive measures. The biggest culprit in attracting pests to Christmas cacti seems to be overwatering. Preventive care, such as discarding infested plants, is a recommended tactic. Pesticides are available for commercial growers, but home growers may not be able to get their hands on them.
By the way, that Christmas cactus you are buying is probably not actually a Christmas cactus. According to the University of Massachusetts Extension Service, holiday cactus is sometimes marketed as Christmas cactus, Thanksgiving cactus, or Zygocactus. The “true” Christmas cactus is an interspecific hybrid of Schlumbergera truncata and Schlumbergera russelliana that originated about 150 years ago in England. It is a common houseplant but is not often grown commercially. Plants have segments with rounded margins, ribbed ovaries and purplish-brown anthers. The correct Latin name for Christmas cactus is Schlumbergera x buckleyi; the “x” indicates that it is an interspecific hybrid. Most commercial cultivars of holiday cactus are actually Schlumbergera truncata, commonly known as Thanksgiving cactus or Zygocactus.
Chaya Kurtz is the editor of Networx.com.