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Foxtail Weed Control: Preventing Foxtail Grass

Weeds are something every gardener has to contend with at some point. Whether it’s lawns or garden beds, weeds can grow anywhere, develop seed heads, and spread seeds everywhere. A battle with weeds can demoralize the efforts of even the most optimistic growers. And one weed that is the bane of gardener existence is the foxtail weed. 

Much like crabgrass, foxtail seeds and foxtail weeds can turn a healthy lawn or pasture into their domain in a matter of a couple of seasons. The growing conditions of this pernicious weed are wide in their range, making persistent and aggressive control necessary in many areas. Some control methods are better than others, though. The method you use will likely be determined by the size and breadth of your property.

Whether you prefer organic, mechanical, or chemical controls, rest assured you can remove foxtails from lawns, pastures, and gardens with the right timing. With proper adjustments and the right herbicide (organic or chemical in some instances), you’ll keep foxtail weeds from germinating again and again, and you’ll save yourself a big headache in the process.  

What Is Foxtail Weed?

Foxtail weed
Many different foxtail weed types exist. Source: Shannon Tompkins

Foxtail is a colloquial name for members of multiple grass, barley, millet, and brome families. The most notorious foxtail plants come from the genus Setaria. Foxtail weeds are widely known for their seed heads that contain fine hairs and barbs that lodge themselves in the feet and maws of animals who may be exposed to them. They look like a fox’s tail, hence the name. The leaf of foxtail is a lot like other grasses: narrow, pointed, and attached to the stem at the node. 

The whole point of the barbed seed head is seed dispersal and proliferation of the foxtail plant. The seed head allows foxtail to self-seed among other grass in dry soil or moist soil, lawns, pastures, and gardens.

Some species of foxtail weeds are annual, and some are perennial. Giant foxtail is a summer annual that emerges in spring and develops seed heads in summer. Other foxtail grasses are perennial and live for several seasons before completing their life cycle. They all have pronounced seed heads that have accompanying fine hairs. The foxtail seed is designed to get into fur, socks, and its barb digs into the skin and can be a huge nuisance to anyone who comes into contact with it. 

Identifying Foxtail Weed

Stems and leaves of green foxtail
Foxtails develop long stems upon which the foxtail seed pod form. Source: NYSIPM

Now that we know about the leaf, hairs, and awns of foxtail, let’s talk about its life cycle. Each foxtail plant goes through different growth phases, exhibiting different characteristics. Let’s cover those now so you have a good idea of what to look for, and when. 

Seedling Phase

Because no seed head has developed in foxtail seedlings, they are difficult to identify. Especially when they are nestled among grass and other weeds, foxtails aren’t easily distinguished at this stage. Another complication is that each species has variable seedlings. One thing to look out for, though, is a parallel plant that has an oblong true leaf 1 inch long and ⅛ of an inch wide. 

Mature Phase

After 40 days or so, foxtail seedlings become foxtail grass. Most species clump together, but some grow singly on one erect stem. The leaves of mature foxtail weeds grow from the base of the stem and twist around it. Fully mature foxtail grass can grow up to four feet tall before seed heads have formed. They tend to pop up in disturbed soil in pastures, lawns, and among varying grass species. Anywhere the soil is disturbed is ideal for yellow, green, and giant foxtail. 

Reproduction Phase

Here’s where the foxtail seed head comes in. Green foxtail has distinct green seed heads that bloom between late spring and late fall. Yellow foxtail has 2 to 5-inch yellow seed heads that bloom from summer to winter. Giant foxtail weeds have 3 to 7-inch seed heads that bloom from summer to late fall and turn yellow in the latter part of their fruiting phase. 

The seeds dislodge from the foxtail seed head when they’re ready to germinate. They are swept up by the wind and either land in soil or lodge themselves in the fur and skin of livestock, pets, and humans. They cling to clothes as well. The seeds can remain dormant for years before they fully germinate. If conditions are right for the seeds, they’ll sprout immediately. Ideal temperatures for these seeds are between 68 and 95 degrees. If you’re gardening in spring, look out for the leaves and seeds of foxtails and control them aggressively. 

Dangers to Pets and Livestock

Dry yellow foxtails
These dry yellow foxtails are a common sight in late summer throughout California. Source: FotoGrazio

Because livestock tends to see these plants as forage, they eat them, causing a host of problems for ranchers everywhere. If you want to create a pet-safe garden, control of giant foxtail, yellow foxtail, and green foxtail is a must. Both livestock and pets can experience infections from the foxtail barb that burrows in one way, making them hard to pull out without doing some epidermal damage. Foxtail plants are especially prevalent if you live near a pasture or prairie where the grass isn’t mowed frequently. Sometimes they pop up in lawns and gardens. 

The foxtail seed barbs carry bacteria, dirt, and debris with them as they burrow. This is another reason they are associated with infection. Dogs are specifically at risk of having problems with foxtail seed because they use their snouts to sense what’s in front of them. The barb of seed heads can get into sensitive areas like the eyes, nose, in between the toes, and mouth. Here it is especially difficult to remove giant foxtail or yellow foxtail seeds, and also where infections have better conditions to fester. 

Foxtails can lodge themselves in the collar region too. The collar region is a place to pay particular attention to, especially in dogs with longer hair. Veterinary sources recommend checking for foxtails frequently in working dogs, and those that live near areas where foxtails grow: in your lawn, pasture, or nearby wilderness where forage grass grows. The same goes for cats who go outdoors. Barn cats are especially susceptible. You don’t want to risk an expensive vet bill for your pet. 

Although it sounds extreme, foxtail can cause death in livestock or pets if it’s not identified quickly enough. Because seed gets stuck in sensitive areas out of sight of farmers and pet owners, it’s very important to check for the awns if foxtail is present on or near your property. An infection left too long could progress outside the range of treatability.

How to Get Rid of Foxtail Weed

Green foxtail
As it dries, the green foxtail releases barbed seeds. Source: NYSIPM

If foxtail grass is prevalent on your property, in your pasture, or your lawn, you have options. You can use cultural methods of control or remove them mechanically. You can kill them with organic or chemical herbicide too. Root out the giant foxtail, yellow foxtail, and green foxtail in your area and you’re well on your way to gardening without risk of stabs (or gardening with weeds)! Or you’ll be one step closer to a yellow foxtail-free healthy lawn. 

Without Chemicals

Mowing is one way to take care of foxtails, especially with the right timing. The key to mowing these grasses is to do so before the seed head has time to form. Since the three species of this forage grass we have discussed tend to bloom from spring to fall, look out for the first signs of flowering in spring, and take the lawnmower to it. If you can get the timing right, and you don’t have a ton of grass in a large area to cover, you can prevent further germination of foxtail seed easily. Otherwise, this method takes a lot of energy and upkeep. Constant vigilance is necessary. 

If foxtails are only an issue in a small area, dig them out, root, leaf, and all. By removing the whole plant you prevent proliferation by seed and by root. If you manage to identify a seedling before the true leaf forms, you can simply pull it out by the root with your hand. In mature plants, you’ll likely need a trowel and some muscle. Even though the roots of these grasses are shallow, they’re sturdy. Kill them this way, or use organic methods of control to rid your property of these forage grasses. 

Organic Foxtail Herbicide

Horticultural vinegar applied to the leaf and awns of green, yellow, and giant foxtails individually is one way to quickly eliminate the plant. If you decide to go this route, make sure you have a mechanism to direct the spray of the vinegar, and that you wear a mask and gloves. This vinegar is not the kind you use in your kitchen and can cause respiratory issues if the vapors are inhaled. Do not spray on a windy day as the vapor can affect the green leaf of a plant living next door to the foxtails you’re trying to get rid of. It can also easily irritate your skin or cause acid burns. Handle this method with caution. Note you may need to reapply the vinegar again in a week or two for full effectiveness.

There are also corn gluten and organic weed prevention methods to remove this plant. One 25 pound bag of corn gluten or cornstarch-based weed killer can cover a large area up to 1250 square feet. Apply these in winter before germination of new seed and water it in. Then, let the area rest for 4 to 6 weeks and reapply as needed at the same interval. Do not apply within 6 weeks of your intended seed planting date as it can also prevent germination of plants you want to grow.

Ortho’s organic form of Groundclear is potentially one of the most effective herbicides on the market for killing weeds. They use the soap salt known as ammonium nonanoate to eliminate weeds in select areas, and they have an OMRI-rated formula that is acceptable for use in organic gardening (but be sure to check the packaging for the OMRI markings, as there is a chemical form of Groundclear as well). Broad-spectrum herbicides like this can take out other plants in the process when applied en masse, so avoid application during windy weather to prevent accidental drift. Ammonium nonanoate breaks down into iron and nitrogen in the soil quickly and does not cause long-term ground pollution. It causes the tissues of the plant to begin to yellow within minutes of application, and the plant wilts to the ground and is unable to photosynthesize. This does not always kill the root systems of more persistent and deeper-rooted weeds, but it takes out most grasses with shallow root systems easily. For other forms of deeper-rooted weeds, you may still need to remove the root after application.

Chemical Herbicide

Giant foxtail
Giant foxtails are a summer annual. Source: NYSIPM

Chemical pre-emergent is one method that’s great for eliminating green, yellow, and giant foxtail grasses in your lawn or pasture. You’ll need to apply the pre-emergent in spring before temperatures get above 55 degrees. Do not do anything with the lawn or pasture for four months after applying. This allows the weed preventer to do its thing and prevents you from wasting time seeding only to have your grass killed as it emerges. 

If you want to wipe out foxtail plants in a giant pasture, use glyphosate. Although those familiar with gardening and ranching know there is a stigma surrounding glyphosate herbicide, sometimes herbicides like it are the best option for several acres to hundreds of acres of land. Using this chemical on the leaf and awns of each specific foxtail grass plant prevents killing of other grasses that benefit livestock and soil ecology too. As with ammonium nonanoate, this method is a spot-treatment method if you’re trying to maintain other plants in the area. However, unlike ammonium nonanoate, glyphosate lingers in the soil and provides continual prevention against weeds for a period of time. You will still need to use it as a spot treatment, but the long-term prevention in treated locations will make your job considerably easier on a large land parcel.

Frequently Asked Questions

Yellow foxtail in autumn
Foxtail seeds break free from their seed head to fly on the wind. Source: autan

Q: How do you identify foxtail weed?

A: Look for the foxtail-like awns with tons of little hairs. The hairs help the seeds spread through the wind. Some of them are green, some are yellow, and some are brown. The leaf of the foxtail plant is oblong and pointed, shooting from the base of the stem. 

Q: Is foxtail weed bad for horses?

A: Yes. Horses see the plant as good forage and eat it. In the process the awns lodge themselves in skin, between hooves, and even in the mouth or tongue of the horse – anywhere they can. This can lead to bad infections that can threaten the life of horses. 

Q: Is yellow foxtail a weed?

A: Indeed. It’s also a type of grass. The leaf of foxtails gives the plant its grassy appearance while the hairs and awns give it the foxy look.


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