Is yarrow a weed?

Yarrow

Yarrow, Achillea millefolium, thrives in soils that are affected by long periods of drought or are lacking in nutrients. The plant spreads by underground stems and also by seeds from its flowers (June to October), which provide an excellent source of nectar for bees. However, once it is established in your garden it will quickly spread, causing particular problems when it appears in the lawn.

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Symptoms

Plant spreads by underground stems and seeds and produces large drought-resistant patches in lawns, so grass cannot spread.

Find it on

all over the garden, but especially on soils affected by drought or lacking in nutrients

Organic

The most effective organic approach is to weaken the plant by hoeing it wherever it appears in beds or borders, or to dig it out using a fork or trowel. If it establishes itself in the lawn you will have to dig out chunks of grass to get it out effectively, but you can hold it at bay by keeping the lawn healthy and thereby making conditions less favourable for the yarrow. Top-dress the lawn in spring and in September, mow it regularly and lightly rake when in growth to weaken the weed.

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Chemical

Yarrow is fairly resistant to many selective weedkillers, but in lawns, use a weedkiller such as a 2, 4-D-based herbicide to remove the weed. Apply in cool, moist, calm conditions when there is least risk of accidentally damaging nearby garden plants.

Yarrow Weed (Achillia Millifolium) in Your Lawn? Here’s How to Remove it

Yarrow weed, or Achillea millifolium is also known as Milfoil.

In fact, like Woodrush and other weeds, Yarrow weed in the lawn can be a sign that your lawn is poor health.

It can also be pretty resistant to selective weed killers which can make getting rid of it a challenge.

But in this article, I’m going to show you how I’d remove it and prevent it from growing back.

Table of Contents

Yarrow Weed in a Nutshell

Before we can treat Yarrow effectively, it’s worth knowing a bit about it.

Appearance

Yarrow is an invasive weed that forms mats of ferny green foliage. It grows from Rhizome stems which grow below the surface of the soil, rooting at intervals.

The roots are tough and fibrous which makes this weed very tolerant to drought.

Although you won’t see them if you mow your lawn, the Daisy-like flowers are borne on stems between June and August and form a flat-topped cluster.

A Perennial Weed

Achillea Millifolium is an aggressive perennial weed, meaning that if not checked, the same weed can live for years.

Preferred Habitat

Yarrow will quite happily grow in all types of soil but it loves dry, chalky soils that are deficient in plant nutrients. In conditions like these, it can grow at an alarming rate, outcompeting the grass.

How to Remove Yarrow Weed From Your Lawn

Like I said earlier, Yarrow weed can be difficult to remove and control but this is how I’d do it;

Dig Out Any Clumps

Yarrow is very tolerant to selective weedkillers so before you waste your money, dig out any plants with a trowel or hand fork. It often helps to rake the weeds first with a springbok rake so you can get a hold of them.

Make sure you remove as much of the roots as possible as it can regrow from root fragments left in the soil.

If your lawn is covered, this might take a while but you’ll need to persevere.

Spray a Weedkiller Concentrate Over the Whole Lawn

If you’ve been thorough then hopefully there won’t be many plants left. However, if you have weeds grow back in your lawn, treat the whole lawn with a weedkiller concentrate.

I recommend Weedol Lawn Weedkiller Concentrate which is designed to be diluted with water and applied with a watering can or knapsack sprayer.

Be sure to dilute the concentrate accurately though. You might be tempted to make it stronger than the instructions recommend but you’ll risk killing the grass. Dilute it too much though and it might not be strong enough to kill the weeds.

So make sure you read the instructions!

Kill it with a Selective Spot Spray Weed Killer

If you treat the lawn with Weedol Weedkiller Concentrate then hopefully this will do the trick. In reality, it’ll probably resist it.

In which case you can either try digging it out again or give it a further treatment 6 weeks later with Resolva Spot Spray Weedkiller for Lawns.

Weedol and Resolva can only be applied once a year so if you treat your lawn with Weedol the first time around, you shouldn’t use it again for a year. The same goes for Resolva.

However, they’re different products with different active ingredients and go about killing weeds slightly differently. So it’s perfectly safe to use them in conjunction with each other.

This will also give you a much better chance of killing the weed once and for all.

Read: The Best Weed Killer For Lawns

How to Prevent Yarrow From Growing in Your Lawn

As I have already mentioned, Yarrow weed thrives in dry, nutrient-deficient soil. So in order to prevent it from growing in your lawn, you should make changes to improve the soil.

The following lawn treatment plan will also help.

Scarify Your Lawn to Reduce Thatch

Thatch is a fibrous layer of organic matter that lies just under the grass but on top of the soil. It’s made up both living and dead grass roots and other matter.

Some thatch is good because it prevents the lawn from becoming diseased. Too much though, and it stops air, water and nutrients from getting into the soil. In turn, the soil becomes deficient in nutrients, water and oxygen so the grass doesn’t grow very well.

This creates the perfect environment for Yarrow to inhabit.

Scarifying your lawn will reduce lawn thatch and open the soil so these vital nutrients can penetrate the soil, giving the grass what it needs to produce food and grow.

Read: Why You Should Scarify Your Lawn and How to Do It

Also Read: What Type of Scarifier Should I Use? How to Choose the Best One For the Job

Aerate Your Lawn to Relieve Soil Compaction

Soil compaction happens when kids or pets play on the lawn, if you walk up and down the same area of your lawn while hanging out the washing, or when the postman takes the same route over your lawn to get to the letterbox.

Over time the forces that go through the lawn push the soil particles together, squeezing out air and water. The ground becomes hard too.

When the soil is so hard and compact, air, water and nutrients can’t penetrate it. Which means the grass doesn’t have access to the nutrients it needs to grow, resulting in patches of threadbare grass.

To relieve compaction, spike your lawn in the spring with either a garden fork or a pair of aeration shoes. Then, hollow-tine your lawn in the autumn to remove cores of turf and soil.

This will allow your lawn to breathe and let water and nutrients penetrate the soil, giving the grass what it needs to produce food and grow strong.

Read: The Ultimate Guide to Lawn Aeration: Why, When and How to Do It

Fertilise Your Lawn

Yarrow thrives in nutrient deficient soil, so, fertilising your soil will prevent it from growing and give the grass what it needs to grow strong.

Nitrogen, Potassium and Phosphorous are critical for grass growth and strength. Apply a good quality fertiliser after scarifying and aerating.

There’s no point doing it before as it won’t be able to get into the soil and you’ll see no benefit.

There are many types of fertilisers available that can be used at different times of the year.

If you’re not particularly green-fingered though, apply a slow-release fertiliser just once a year. Your lawn will look much better for it.

Read: Everything You Need to Know About Fertilising Your Lawn

Also Read: The Best Lawn Feed and Weedkiller: My Recommendations

Mow the Lawn Regularly

One of the secrets and most important part of maintaining and healthy, weed free lawn is to cut the grass regularly.

Regular mowing keeps the height of the grass relatively low. When it is prevented from growing upwards, it adapts and grows sideways producing new shoots and new leaves. All this results in lush, thick grass.

Cutting your grass much more than walking up and down the lawn once a fortnight though. There’s more to it than that, especially if you want a lawn to be proud of.

Read: How to Mow the Lawn Like a Pro

Also Read: Which Lawn Mower is Best? My Top 7 Picks

Now it’s Your Turn

Removing Yarrow weed can be a challenge so ready yourself for battle. It can take a while a while to completely get rid of it so you’ll need to equip yourself with plenty of patience.

But killing weeds is only have the battle, preventing them from growing in the first place is where the work is.

That said, it’s not hard work. It just takes a little bit of knowledge and the commitment to apply it.

  • Scarify once every couple of years to keep lawn thatch under control,
  • Aerate compacted areas in spring and autumn
  • Fertilise at least once a year
  • Cut the grass regularly

That’s all there is to it.

You’ll be amazed at the difference you see in your lawn.

Speaking of which, if you’re on a mission to rid your lawn of its weeds, take a before and after picture and send it in. I’d love to see them and share them with our community.

And as always, if you have any comments, questions or suggestions, leave a comment below.

Botanical name: Achillea millefolium
Family name: Asteraceae

Yarrow is commonly found in pastures throughout New Zealand, though it is not really a weed (“unwanted plant”) in pastures. It was once sown as a pasture species because of its ability to tolerate dry summer conditions with its deep rhizome system, and also because it has higher quantities of some minerals than perennial ryegrass or white clover. It is still sold in New Zealand in pasture mixtures for organic farming systems. However, yarrow becomes a problem when a paddock is cultivated and a crop sown. The rhizome system allows the yarrow to survive cultivation, so the re-establishing plants cause major competition problems with crop plants. Likewise, yarrow is commonly found in turf. Once established in a lawn, yarrow is very tolerant of frequent mowing. However, it is unable to form seed-heads under constant mowing, so instead relies on vegetative spread by rhizomes to produce new plants. Yarrow is commonly found in waste areas and road-sides too, where the plants are better able to produce the characteristic white flower heads.

Distinguishing features

The finely-divided leaves of yarrow look similar to those of several other weed species. In turf, it can be confused with Onehunga weed, but yarrow has about 15-20 leaflets down each side of a leaf, compared with about 5-8 leaflets per side in Onehunga weed. In pastures, it might be confused with stinking mayweed, but it does not have the strong aroma when crushed that exists with stinking mayweed. Also, neither Onehunga weed nor stinking mayweed has a rhizome system underground like that found with yarrow. Vegetative plants of yarrow produce leaves from a growing point situated at ground level, making it tolerant of defoliation by animals or mowers. In situations where yarrow is able to flower, an upright stem forms and flower heads are produced which consist of many small white flowers which cluster together to create a conspicuous mass.

Control

As with most perennial weeds with rhizomes and creeping roots, yarrow is much harder to kill than annual weeds. Cultivation cuts up the rhizome system, and regrowth occurs from each rhizome fragment which is not left on the soil surface. Rhizomes will dry out and die if left at the surface. Deep burial can also kill the rhizomes, but generally there are enough sugars stored in rhizome fragments to allow regrowth of foliage back to the soil surface if rhizomes are only buried at a shallow depth. Most herbicides give poor control because insufficient chemical moves into the rhizome system to kill it. Herbicides capable of translocating into the rhizome such as glyphosate, amitrole and clopyralid are required for good control. In fact, even glyphosate does not give great control, so often tribenuron (eg Granstar) is recommended to be added to glyphosate plus a surfactant when spraying out pastures which have yarrow present to improve control.

How to Kill Weeds in your Lawn

Before you Start

In order to successfully control weeds in your lawn, it first depends on the type of weed you have and then select the appropriate weedkiller.

Never use a regular weedkiller on your lawn. It will of course kill your weeds, but it will also kill your grass, leaving you with bare patches!

The right Weedkiller for your Lawn

The most effective way to ensure you eliminate them completely is to use a weedkiller which has been developed specifically for lawns, like Resolva Lawn Weedkiller.

This powerful weedkiller is easy to use and gets straight to the roots of the weed, but doesn’t affect your grass, leaving you free to get on with the mowing! It controls a wide range of broad leaved weeds such as Dandelions, Daisies, White Clover, Buttercups and Yarrow. The product as available in both 1 litre and 3 litres ready to use trigger spray for small areas or liquid shots.

If you have a large area of weeds to kill on your lawn, it is worth using Resolva Lawn Weedkiller Extra Concentrate to treat up to 250m2.

Alternately also recommend Aftercut All in One as a triple action lawn treatment that will effectively green your lawn within 7 days, kills moss, kills weeds and their roots and ultimately gives you a stronger lawn.

Yarrow Control: Tips To Remove Yarrow

Yarrow, a perennial plant with feathery leaves that may be both a blessing and a curse in the home landscape, is often called yarrow weed. Ornamental or common yarrow is not native, but Western yarrow is indigenous to North America. Both have a spreading habit and extremely tolerant, hardy natures. It’s the spreading habit that is of most concern to homeowners. Once the plant is in your yard, it’s there to stay and it can be very difficult to remove yarrow.

What is Yarrow?

Yarrow is a low-growing plant that produces flower stalks four times its foliage height. The plant is recognized by the feathery almost fern-like green foliage. Each leaf is between 1 and 6 inches long. Each plant can produce several flower stalks covered by fine hairs.

Flower heads are borne in corymbs or umbrella shaped clusters. Each flower has five colored flowers surrounding 10 to 20 pale yellow florets. The flowers are commonly white or soft pink but now come in yellows,

coral and red.

Is Yarrow an Invasive Weed?

The answer to that question is complex but really boils down to opinion. Many people appreciate the easy care nature of yarrow and there are several new cultivars that are introducing new colors and sizes to the home landscape. Yarrow produces season-long umbrella shaped flower clusters that enliven the garden. There are also those who find the plant colonizing entire beds and even the grass. That would classify it as an invasive weed. In these gardener’s minds, yarrow control is paramount.

Yarrow is an extremely adaptable plant. It can grow on any soil and in many conditions. It spreads from its rhizomes. When the plant is disturbed and small piece of rhizome can become a whole new plant. The clustered flowers on their 3-foot tall stocks produce thousands of seeds. The tiny seeds spread by wind and can remain viable in soil for up to nine years. The longevity of the seeds makes complete yarrow control impossible.

How to Remove Yarrow

Killing Yarrow without Chemicals

It’s much nicer to use the term yarrow control but the goal is the same — to eliminate yarrow plants. Digging and hoeing areas where yarrow has spread can remove some of the rhizomes but mechanical control is only effective if it goes down 12 inches and removes every speck of yarrow weed. Providing superior care to the lawn will make it thick and prevent some of the spread of the pest.

Chemical Yarrow Control

There are several chemicals available for killing yarrow. They must be used during the period of growth from spring to autumn. Dicamba, chlorsulfuron, clopyralid, MCPA, triclopyr and 2,4D are all listed as useful for yarrow control by the University of Illinois. Yarrow will require several treatments over the growing season, so it’s best to define the problem early and apply controls as soon as possible. Remember to follow all precautions listed by the chemical manufacturer.

Yarrow
Achillea millefolium
Did you know?

An extract from yarrow can repel mosquitoes!

What is yarrow?
Yarrow is a common perennial forb with many subspecies that are difficult to distinguish visually. Our purpose is not to differentiate between subspecies, but the information will primarily refer to western yarrow (Achillea millefolium ssp. occidentalis).

Native Americans used yarrow to make a tea to relieve ear, tooth, and headaches; to reduce swelling; and as a stimulant. During the Civil War, yarrow was used to treat wounds and became known as “soldiers’ woundwort.” If collected just before it flowers, a tea can be made using the newest leaves. An extract of yarrow also repels mosquitoes.

What are its characteristics?
Yarrow grows 10 to 30 inches in height, with extensive rhizomes and numerous stems. Fern-like leaves and clusters of tiny white flowers give it a distinctive appearance. Leaves may be covered with tiny hairs, and the basal leaves can remain green throughout the winter.

The adaptability of yarrow allows it to grow in a wide range of habitats and growing conditions. It is very drought-tolerant, and its life cycle is completed by the onset of the summer drought and fire season in July. Following fire, regeneration is rapid from rhizomes and wind dispersed seeds. Yarrow can increase rapidly in disturbed areas or overgrazed rangelands. It tends to diminish once the disturbance is removed.

What’s its value to the Great Basin?
Yarrow commonly occupies dry, open sites in a variety of habitats across its range. It can persist on thin soils, and help prevent soil erosion. Browsing animals like sheep, pronghorn, and deer use it, but most often graze only the flower heads. Yarrow is a particularly important food source for sage grouse chicks.

What is its restoration potential?
Rhizomes, ability to re-sprout, high germination rates, and competitive seedlings make yarrow remarkably persistent with fire and other disturbances. It often is one of the first native species to appear on disturbed sites. It has also been used successfully in many revegetation projects. Yarrow doesn’t burn easily, and can be planted as a fire barrier in fire-prone areas, or around property and fire-sensitive areas.

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Weed of the Week: Yarrow (Achilles millefolium)

Weed of the Week: yarrow (Achilles millefolium)

By Laurence Gale

What is a weed? By definition a weed is a plant that is growing in the wrong place. Weeds take valuable space, water, sunlight and nutrients that may otherwise be accessible to important crops, in our case turf grasses. Weeds not only compete for these resources they can disfigure and cause problems to playing surfaces.

Weeds are very good competitors and take advantage of any opportunities to colonise turf situations, particularly when the sward is under stress and weak, leaving bare soil areas for weeds to populate. Weeds have many mechanisms and characteristics that enable them to do this, having thick waxy cuticle leaves that can be resistant to some chemicals, fast reproduction methods, the ability to reseed in 6 week cycles and deep tap roots enabling the weed to survive in compacted dry ground conditions.

Weeds have one of three life cycles: annual; biennial or perennial.

  • Annual weeds: Live for a single season. These weeds germinate from seed in the spring or summer, flower and then die.
  • Biennial weeds: Live for two seasons. During the first growing season, these weeds remain in a vegetative stage and, in the following year, produce flowers, set seed and die.
  • Perennial weeds: Live for multiple seasons and flower more than once. Perennial structures (rhizomes, stolons, crowns, entire plants or roots) survive from year to year.

Some weeds may be harmful to the environment or noxious to your regional ecology. For example Japanese Knotweed (Fallopia Japonica) is fast becoming a major weed problem on road side verges and urban landscape areas, a very difficult weed to eradicate. It is very important to recognise weeds and seek effective controls methods to eradicate them from our facilities.

Weeds can also be used as an indicator of soil conditions. For example, knotweed and plantains both indicate soil compaction because they can maintain adequate root respiration at lower oxygen diffusion levels than other plants. Different weeds tolerate different soil conditions, some are alkaline loving and others acid loving. Getting to understand and recognise the physiology of these plants will help you become better turfgrass managers.

This weeks weed is: Achilles millefolium (common yarrow)

Scientific name

Family

Life cycle

Achilles millefolium .

Asteraceae, formerly Compositae

Perennial

Form / Appearance The leaves are lanceolate and divided into narrow segments, appearing fern-like. The leaves of yarrow are strongly scented. Yarrow flowers are rarely seen in mowed situations.
Roots Yarrow has a very fibrous root system that consists of many rhizomes which play a major role in the plant’s ability to establish itself in turf and make the plant difficult to eradicate.
Flowers White or yellow flowers are formed at the ends of stems in dense, flat clusters. Flowering occurs in June to October.
Leaves Leaves on mature plants are finely dissected, giving them a feathery appearance, and resemble a fern.
Reproductive method Yarrow reproduces itself from seed and Rhizome development.
Habitat Yarrow is a drought tolerant perennial that can endure dry, impoverished / infertile sandy soils and survive with little or no maintenance. Yarrow’s main growth period is from April through to September. Yarrow is a good indicator of infertile soil conditions.
Miscellaneous info Yarrow is also known as milfoil, thousand leaf or woundwort. Yarrow is used as medicinal remedies by herbalists, it has been valued since ancient times for its ability to stop bleeding, hence its nickname “nosebleed.” Today, yarrow is valued for its ability to fight off colds and flu. Yarrow is a tough, durable and aromatic weed.
Cultural Control Yarrow can be mechanically or physically removed. Care should be taken to assure that all roots are thoroughly removed. Close mowing prevents seed head formation, whilst maintaining a dense sward will deter or prevent yarrow from establishing. Good soil fertility is essential, maintaining a soil pH of 6.5 to 7.
Chemical Control Apply selective broadleaf herbicides when plant growth is active. There are a number of products available for controlling broad leaf weeds in established turf.

These chemicals are best used when the weeds are actively growing, usually between April-October.

  • Tritox (Contains 178g/L (16.2%w/w) MCPA 54.g/L(4.9%w/w) mecoprop-p and 15g/L (1.4%w/w) dicamba and potassium salts. Scotts.
  • Intrepid 2. (Contains 20.8g/L dicamba,166g/L dichlorprop-p ans 166.5g/L MCPA). Scotts.
  • Greenor. (Contains: 40g/L fluroxypyr, 20g/L clopyralid and 200g/L MCPA). Rigby Taylor.
  • Bastion T. (Contains: 72g/L fluroxypyr and 300g/L mecoprop-p ). Rigby Taylor.
  • Dormone (Contains 465g/L2,4-D(38.1%w/w) as the diethanolamine salt). A herbicide which can be used near water. Bayer Environmental Science.
  • Supertox 30 (Contains 95g/L (8.8%w/w) mecoprop-p and 93.5g/L(8.7%w/w) as the diethanolamine salts). Bayer Environmental Science.

These herbicides are usually applied as a liquid using watering cans, knapsack sprayers and vehicle mounted sprayers.

Ensure you follow manufacturer’s directions, health & safety and product data sheets, and comply with COSHH regulations, when using these chemicals.

Herbicides are an effective tool where high quality turf is desired. However, they must be applied with care and accuracy and in the context of a good overall turf management program. Before using any herbicide, carefully review the label for conditions of use including rates, methods of application, and precautions. Never use an herbicide in any manner contrary to its label and be sure that the herbicide will not injure the turfgrass species

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