Q: I’ve noticed a considerable amount of onion grass in my lawn as well as loads of it in other neighbors’ yards. Is it because of the scant snow we had? And what’s the best way to eradicate it?
A: Two common weeds are wild onion and wild garlic. They are perennial, both spread by seed, bulb and bulblet. Both are edible but resemble other plants that are not. To some, wild garlic smells like onion and wild onion smells like garlic.
While the control methods are the same, you can identify which weed you are battling by looking at the leaves or bulbs:
•Leaves: Wild garlic (Allium vineale) has two to four long narrow leaves that are round and hollow. Wild onion (A. canadense) has more than two leaves, also long and narrow, but they are somewhat flat, slightly convex and not hollow.
•Bulbs: Other distinguishing features are the appearance and color of the bulbs. Wild garlic bulbs have a yellowish-brown outer membrane and fibers that run from top to bottom. There are often several bulblets within the membrane. Wild onion bulbs are brown with a pattern. There are one to three bulblets and the cut surface of a bulb will turn red when exposed to the air.
Wild garlic has an economic impact as well as an aesthetic one. In addition to its offensive habit of rapidly growing in lawns and beds, it makes milk smell if the cows eat it, and taints grains grown near it making them stink as well. Both affected grain and dairy products are rendered unfit for sale.
If you are determined and willing to devote time and effort to the project, there are a few options for controlling wild garlic and onion weeds:
•Small patches: Pull or dig it out. This will take several years. Bulbs mature at the same time that the red maple tree flowers. Start digging several inches away from the clump, removing all bulbs that you find and trashing, not composting them. The bulbs have a lifespan of up to six years so any that survive the compost pile can reinfest your garden. If you repeat the process at two- to three-week intervals from fall to spring for several years, you may get rid of most of the weed.
•Lawn areas: You can slow the spread by regularly mowing down the greens. This will somewhat weaken the bulbs and decrease the seed and aerial bulblets. It won’t eliminate the problem but at least it will take longer to spread.
•Herbicide: A post-emergent herbicide may be applied during active growth periods of the wild garlic/onion. Treat plants when the greens are between 2 and 8 inches tall in the fall, winter and spring. Look for herbicides containing 2,4 D, MCPP, and/or dicamba in a variety of combinations. Check individual herbicides for use and effectiveness against wild garlic/onion and be sure to protect nearby desirable plants. There are no effective pre-emergent herbicides.
•Mulch: Mulch, applied at a depth of 4 inches, has shown some success in deterring the growth of wild garlic/onion. There is a trade-off because deep mulch can cause other problems with vermin, mold and disease.
Promenade plant exchange
Q: I just heard the rumor that the plant exchange held annually at the Promenade will not occur this year. Is this true? My daughter and I so look forward to this event.
A: Unfortunately, the rumor is true. My contact at the Promenade Shops at Saucon Valley informed me recently that they will not be able to accommodate the event this year and it is too late to find another site and organize the event. It has been one of my favorite events. If the Promenade determines that it is unable to continue hosting the event in the future, I will look for a new site for next year.
•Catasauqua Garden Club: Annual plant sale: 9 a.m. to 1 p.m., May 4, or until plants are gone. Come early to the Catasauqua Library at Third and Bridge Streets for the best selection.
•American Rhododendron Society, Lehigh Valley Chapter: Annual plant sale, 9 a.m. to 2 p.m., May 11, at the Bethlehem Area Vo-Tech School, 3300 Chester Ave., Bethlehem. Unusual rhododendrons and azaleas. Cash or check only.
•West Ward Neighborhood Partnership, Easton: Spring Plant Exchange, noon to 3 p.m., May 4, 630 Northampton St., Easton. Bring a plant, take a plant — clearly marked bulbs, tubers, rhizomes and plants, please no invasive plants. A limited amount of shrubs will be available for a donation and a selection of herbs and plants will be available for sale.
Sue Kittek is a freelance garden columnist, writer, and lecturer. Send questions to Garden Keeper at [email protected] or mail: Garden Keeper, The Morning Call, P.O. Box 1260, Allentown, PA 18105.
This Week in the Garden
•Start seeds for: Pumpkins, eggplant, summer squash, and winter squash. Continue sowing: Eggplant, summer squash, and winter squash, baby’s breath, cosmos, and zinnias.
•Direct sow: Celeric, celery, cabbage, carrots, collards, bunching onions, onion sets, parsnips and Swiss chard. Continue sowing cabbage, carrots, collards, bunching onions, onion sets, parsnips and Swiss chard, Chinese cabbage, endive, escarole, kale, kohlrabi, leeks, head lettuce and leaf lettuce, beets, broccoli, Brussels sprouts, cauliflower, peas, radishes, spinach and turnips.
•Plant bare root trees and shrubs when soil is dry enough to work.
•Plant perennials and cool season annuals.
•Visit nurseries for inspiration and new plants. Shop for summer bulbs.
•Prune and divide perennials. Hostas and daylilies are up and ready to divide.
•Cut back ornamental grasses. Divide clumps when you see new growth.
•Test soil for new beds.
•Apply broadleaf weed control in the lawn by the end of May. If you use corn gluten based weed control in garden beds, begin applying now and repeat as directed.
•Dethatch lawns by mid-May.
•Apply spring lawn fertilizer treatments by mid-June.
•Complete sod projects by the end of May to allow the grass to establish before the heat of summer.
•Seed lawns now until mid-May.
•Apply top dressing of compost to lawns and beds.
•Fill in holes or dents in lawns before seeding or sodding.
•Apply or fluff spring mulch. It should be 2 to 3 inches deep and applied a few inches away from foundations, tree trunks and other plants.
•Dump standing water and remove anything where rainwater can collect in stagnant pools. Mosquitoes can breed in small pools of water.
•Clean gutters and down-spouting.
•Check hoses; replace washers and correct leaky connections before connecting to water source.
- Wild Garlic Control: How To Kill Wild Garlic Weeds
- Wild Garlic in Landscapes
- How to Kill Wild Garlic Weeds
- Methods to get rid of wild onions and wild garlic in your yard
- Wild Onions versus Wild Garlic – Similarities and Differences
- Controlling Wild Onion/Garlic – What you should NOT do
- Best methods to control Wild Onions/Garlic
- How to get rid of wild onions without damaging your lawn
- Killing Wild Onions or Wild Garlic with Chemicals
- Is wild onions / garlic edible?
- Do Wild Onions or Wild Garlic cause any problems in my lawn?
- Wild Garlic & Wild Onion
- Wild garlic
Wild Garlic Control: How To Kill Wild Garlic Weeds
I love the smell of garlic sautéing in olive oil but not so much when it permeates the lawn and garden with no sign of abating. Let’s learn how to get rid of wild garlic weeds.
Wild Garlic in Landscapes
Wild garlic (Allium vineale) in lawns and garden areas can be found throughout the southeastern United States along with its almost indistinguishable relation, the wild onion (Allium canadense). A true annoyance, wild garlic grows rampantly during the cooler months and controlling wild garlic can be a challenge, not to mention the stench that may linger for hours after mowing or cutting.
As they are both similar in nature, wild onion and wild garlic control are also similar with a few exceptions – wild garlic is more commonly seen in crop-like areas and wild onion most common in lawns. This is not always the case, but can make a difference when it comes to treatment since you do not want to introduce chemicals in areas where you grow edibles. When identifying wild onions vs. wild garlic, it helps to know how they’re similar and how they’re different.
Both are perennials, coming back each year, and can be problematic in spring. Though senses of smell vary, it is often stated that wild garlic smells more like onions while the opposite is true for wild onions, smelling more like garlic. Both have narrow leaves but wild garlic only has about 2-4 while wild onion has many more.
Additionally, wild garlic plants consist of round, hollow leaves and wild onions are flat and non-hollow. The bulb structure for each slightly differs too, with wild onions having a fibrous net-like coat on the central bulb and no offset bulblets, and wild garlic producing offset bulbs enclosed by a papery membrane-like skin.
How to Kill Wild Garlic Weeds
The question “how to kill wild garlic weeds” can involve a number of suitable methods.
Controlling wild garlic can be accomplished by hoeing during the winter and early spring to prevent new bulbs from forming. The bulbs of wild garlic may lay dormant in the soil for up to 6 years and nothing sprayed above ground level will penetrate and control wild garlic. Getting rid of wild garlic completely may take 3-4 years utilizing a combination of methods with hoeing as one option, especially in garden beds.
Wild garlic may also be pulled; however, the chance of bulbs being left in the soil minimizes the likelihood that wild garlic control has been attained. It is better to actually dig the bulbs out with a trowel or shovel. Again, this works well for smaller areas and gardens.
And then there is chemical control. Wild garlic doesn’t respond well to herbicides due to the waxy nature of its foliage, so chemical control of this weed can be somewhat difficult to say the least and it may take several attempts before you see results, if any. There are currently no herbicides which are useful for controlling wild garlic pre-emergence. Rather, wild garlic must be treated with herbicides after the bulb has begun to grow shoots.
Apply herbicides in November and then again in late winter or early to mid-spring, with greater results in lawns following mowing to improve uptake. It may be necessary to retreat again later in spring or the following fall to completely eradicate wild garlic. Select herbicides which are suitable for the landscape site where they are being applied and deemed most effective for use on wild garlic weeds, such as the application of 2.4 D or dicamba, when the weeds are 8 inches tall. The amine formulations of 2.4 D are safer then the ester formulations. Post application, refrain from mowing for 2 weeks.
Examples of suitable products containing 2.4 D are:
- Bayer Advanced Southern Weed Killer for Lawns
- Spectracide Weed Stop for Lawns – for Southern Lawns, Lilly Miller Lawn Weed Killer, Southern Ag Lawn Weed Killer with Trimec®, and Ferti-lome Weed-Out Lawn Weed Killer
These three-way broadleaf herbicides are safe for use on most turf grasses with the exception of St. Augustine or Centipede grass. Do not apply during the spring greening up of warm-season turfs, newly seeded lawns or over the roots of ornamental trees or shrubs.
Lastly, the final option the battle of getting rid of wild garlic is called Metsulfuron (Manor and Bladet), which is a product that should be applied by a landscape professional and, thus, may be a bit more costly.
Methods to get rid of wild onions and wild garlic in your yard
If you are reading this post then you’ve seen them. Those pesky tall dark-green to white stalks rising above your grass in the Fall and Spring that will dull your lawnmower blade. Well, there are really only a few effective ways to get rid of wild onions (also known as onion grass) and wild garlic that are established,
- Dig them out, removing the bulb/roots (organic, most effective, minimal disturbance/damage to your lawn)
- Leave them. They don’t actually harm anything, but just look bad.
- Ignore them, as they are dormant during most of the growing season
- Use vinegar or boiling water to kill them (organic, most effective). But this will kill any grass too.
- Use chemicals to kill them (partially effective)
They grow at a fast pace in late fall and Spring during cooler temperatures (when your regular lawn isn’t growing much). So, you will see the isolated green clumps sticking above your lawn. And wild onions and garlic can be very noticeable and unsightly. I will say this though – as tempting as it is, you should NOT pull them. Unless you have very loamy, black, crumbly soil, you will likely break the stalk, leaving the bulb. This means the plant will come right back and sprout more ugly stalks.
Wild Onion and Wild Garlic – a hundred year old problem!
Back at the turn of the century (19th/20th that is) farmers were advised to plow their fields in the winter to help kill off these bulbs. As the turning of the soil would expose most of the new bulbs to the elements, killing them. If they neglected to do this they risked having their wheat taste bad, resulting in lower prices. Or having their cows milk taste sour, and would be unable to sell it.
Wild Onions versus Wild Garlic – Similarities and Differences
Wild onions/garlic are any Alium species that wasn’t cultivated by you. So, basically any Alium growing in your lawn.
The primary difference between Wild Onion vs. Wild Garlic is the leaves. Wild onion will have many leaves coming from one stalk, while wild garlic will have single, tubular, hollow leaf coming right from the ground.
Since they are of the same genus, they are more similar than different. For example, the most common similarities;
- Both grow during cooler temperatures, namely Early Spring and Autumn
- Both will grow taller than your grass at this time, since your grass is likely to be slow growing or dormant due to cooler temperatures
- Blades/leaves from both have a strong garlic or onion odor
- Both are perennial, meaning they will come back year after year unless you remove/kill them.
- Both wild onion and wild garlic will have a very distinct, pungent garlic-y smell when disturbed/cut
Wild Onion has flat, broad leaves all coming up from one stalk. There are numerous different species that could be present in your lawn. Basically one bulb can produce many leaves all coming from the same stalk. Also, the leaves may spread out or hang down, like a very ‘upright’ tall version of crabgrass. If you cut a leaf of wild onion, it will not be hollow.
Wild garlic is native to Europe/Asia/Africa and was introduced as a food source by colonists. This is a perennial bulb that will eventually from into clumps of individual bulbs/stalks. It has spread via seeds/bulbs and is generally present throughout the Eastern United States, into the Midwest and along the West Coast. When people talk about wild onions growing in their lawn, they are most commonly referring to wild garlic. The bulbs are generally 3-6″ below ground. If you cut a leaf of wild garlic – it will be hollow.
Wild garlic – note the hollow stem.
Controlling Wild Onion/Garlic – What you should NOT do
Don’t ever pull on the tall stalks of wild garlic. The stalk will almost always break away, leaving the bulb full in-tact in the soil. Nature has engineered this plant to survive losing its stalk/leave! It will just send up more stalks at a later time. Perhaps in a week or two if it is during the Early Spring or Fall. I repeat – don’t pull wild onion/garlic. If you break the stalk, you will most certainly be leaving the bulb behind, and will just have to attack it again at a later date.
Best methods to control Wild Onions/Garlic
If you don’t have 300 plants poking up through your grass, then this is the most effective organic way to remove& kill the plant. Also, it can be more effective than chemical, since the herbicide will often fall right off the stalks or leaves, as they are quite narrow. One very important tip is that you should wait until after a rain to dig out the bulbs, as it is much easier in moist/wet ground. And above all else – you must make sure you get all of the bulbs/roots.
The bulbs will be deeper than your grass, so you need to make sure you dig about 6″ (15 cm) deep. Doing so will ensure you most likely get underneath the bulbs, and provide the best opportunity for complete removal.
The simplest way to remove the plant is to dig up the entire plant with a shovel/trowel. You must make sure you remove all of the bulbs/stalks – basically everything. Leaving any part behind will likely result in a new plant growing. Just stab the shovel into the ground near the stalks, and dig them up. Make sure you get the entire bulb/root mass.
How to get rid of wild onions without damaging your lawn
I have developed a really good trick for getting rid of the entire plant, without leaving gaping holes in my lawn. As with the shovel method, you should do this when the ground is moist to make life easier. This can be done with a shovel, or a pitch fork. But what I will do is stab the pitch fork or garden spade about 4-6″ away from the clump of stalks, and make sure it penetrates deep into the ground.
Hold it at approximately 30 degrees from vertical, so that the trajectory will put the tip of the shovel/pitchfork beneath the bulbs (about 6″ / 15 cm deep). Then just gently rock it back, while gently pulling on the onion talks at the same time, until you can flip over or feel under the chunk of sod. (See video below)
Next, look for a clump white stringy roots poking through the dirt. This will be the group of onion/garlic bulbs. Remove some of the dirt until you can get the clump of bulbs inside your fist, then take your other hand and hold the sod, and pull. You are kind of pulling weeds in the reverse direction, in that the stalks are going down relative to the sod. By doing this you will be removing the entire bulb and stalk, without doing much damage to your lawn/yard. Since the bulbs are most likely to be an inch or two (5 cm) deeper than the grass roots, you haven’t done much mechanical damage to the grass, as they will still be intact. As a final step, just put the chunk of sod back where you dug it up, and nobody will even notice that the wild onions were there.
This entire operation is about the same as if you ran an aerator over this small chunk of sod. So, no real damage, and will reduce compaction at the same time. One less weed, and more room for your grass roots – that is what I call a win/win! The video below details the process;
Killing Wild Onions or Wild Garlic with Chemicals
Since neither are ‘broad leaf’ the common weed killers don’t work well on Onion Grass or Wild Garlic. This is the same problem you have may have noticed on controlling Nutsedge. Broad leaf weeds have a lot of surface area that the herbicide can stick. Wild onions, and wild garlic in particular have small surface area, meaning that it is harder to apply a lot of herbicide. In addition to this, they have a slight waxy coating to protect themselves. So, smaller surface area combined with a coating that sheds weed killer means that most weed killers may not be effective. In addition to that – they have a bulb deep in the ground, that can store a lot of energy to help the plant survive a herbicide attack. Thus, you have a trifecta of herbicide resistance, small round leaves, waxy coating, and an energy filled bulb to resist herbicide. So – you can kill it with conventional herbicides that won’t harm your lawn, but it may take a loooong time.
What herbicides easily kill wild onions?
Certain herbicides have been tested in labs to see when is the best time to spray in terms of the plants age. Research found that spraying herbicide when the plant was young, at the 2-leaf stage was the most effective way to damage the plant. The problem with that is you don’t notice the plant at that stage very much! It most likely just blends in with your lawn.
There a couple of herbicides that have been found to be very effective at killing Wild Onion. Paraquat was found to be very effective at killing Wild Onions in the Spring. While Imazaquin was found to be an effective herbicide when applied in the Fall. Imazaquin is available on Amazon in concentrate form. If you have a severe infestation, and don’t mind using chemicals to kill Wild Onions, then that would be your best option. Just apply it in the fall.
When should I spray wild onions and garlic?
Well, if you have a ridiculous infestation, then you should apply your herbicides after mowing, when the center of the stalks have been cut and are exposed. Or, follow the advice above and apply Imazaquin in the Fall. This will raise the probability that enough chemical will enter the plant to kill the bulb.
What conventional chemicals will kill it?
Glysophate (round up) will kill it, and everything else, but may require multiple applications, and benefits from the wild onion plant having been just mowed to expose the interior stalk. Regulare 2-4-D/Cambria herbicides can kill it with enough applications, but you should do it right after mowing.
As stated above, the easiest readily available herbicide to use on Wild Onions is Imazaquin. You can get it on Amazon here.
What other liquid herbicides can kill it?
A large dose of vinegar in the soil can kill wild onions and garlic. Also, if you boil a pot of water and apply it to the plant, this should kill it too – and all the surrounding grass that is exposed to the intense heat.
Is wild onions / garlic edible?
Warning – there is one other look alike weed that is actually deadly. Death Camus looks very similar to wild onion in many ways. However, it doesn’t have that pungent smell that the wild garlic/onions have, and outside of that you need to wait until it blooms to make a positive ID. But fair warning – I take no responsibility for you consuming plants growing in the wild. You do so at your own risk.
But back to the main question – are wild onions or wild garlic edible? Yes. Both are edible, and can be somewhat nutritious in minerals. For instance, you can use the stalks as a substitute for chives, or as a general seasoning. They are each quite similar to scalions. However, remember, both of these plants have very pungent garlic-y or onion-y smells. If the plant doesn’t have a strong smell, don’t eat it (never thought I would type that sentence).
Do Wild Onions or Wild Garlic cause any problems in my lawn?
In a nutshell – no they don’t. They displace grass, and don’t fit in with a uniform lawn, as they will grow taller than your turf during Spring/Fall. But that is it – other than that they cause no harm to your lawn. Although they are much tougher on your lawnmower blade than Fescue or Bermudian grass.
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NATIVE PLANT GROWING FACT SHEETS
As the season changes so do the spectrum of weeds in our fields. Winter annuals and cool season perennials emerge as the summer annuals wither and fade. There are many winter weeds that can be problematic in nursery fields; however, the weed that rules the winter landscape is a bulbous perennial. Wild garlic (Allium vineale) is one of the most troublesome weeds in nursery production. This article will describe the biology and life cycle of wild garlic, and how to use that information to develop an effective control program.
Wild garlic is a cool season perennial in the family Liliaceae. It grows in small grass-like clumps from late fall through early spring. Wild garlic is problematic in wheat crops because its aerial bulblets (explained below) are difficult to separate from wheat grains. Contamination of this type can ruin the flavor of bread and other products made from wheat. It has also been suggested that cows that eat wild garlic have off-flavored milk.
So why is it a problem in nursery crops? We don’t eat nursery crops. Furthermore, because wild garlic has a small and shallow root system, it does not compete with crops for nutrients and water. The major issue with wild garlic in nursery production is that our customers do not want this weed in their fields or landscapes. Shipping nursery stock with wild garlic bulbs in the rootball will likely cause problems with your customers, who will not appreciate the ‘bonus’ plants. This ultimately reduces the perception of quality in your nursery’s product.
Wild garlic structure
Wild garlic leaves are hollow and circular in cross-section. Wild onion (Allium canadense) is often confused with this plant, however, its leaves are flat and solid. Wild onion is also fairly easy to control and does not persist in cultivated crops, so its occurrence is not likely in maintained nursery stock.
Wild garlic plants can be divided into two main categories, scapigerous and non-scapigerous plants. Scapigerous plants are those that produce a flowering scape (a leafless peduncle). Non-scapigerous plants are those that do not.
Wild garlic reproduces by seed, aerial bulblets, and underground bulbs. Seed are thought to be a relatively minor pathway for plant dispersal. Seed are viable when produced. However, flowering scapes (and thus seed) occur on only a small percentage of plants in each field. Furthermore, scapes don’t develop until early summer (May to June) and they grow to a conspicuous height of approximately 2 feet. Thus it is unlikely that scapes avoid mowing, hoeing, cultivating, herbicide applications, and all the other forms of weed control that occur throughout the spring and early summer.
Aerial bulblets also form at the terminal end of scapes, often just below flowers. A single plant can produce from 20 to 300 aerial bulblets. Developing bulblets are enclosed in a spathe, which is a dry, thin, membranous bract that surrounds the bulblets until maturity. In other agricultural crops, aerial bulblets are commonly thought to be the primary mechanism by which this plant spreads. More aerial bulblets are produced on a plant than underground bulbs. However, flowering scapes are not likely to go unnoticed nor uncontrolled in a decently maintained nursery field. So just like flowers and seeds that also occur on the flowering scapes, aerial bulblets are probably not important in the spread of this plant throughout nursery fields.
There are several types of underground bulbs produced by wild garlic including offset bulbs, central bulbs, and hardshell bulbs. Offset bulbs are formed by scapigerous plants only. One offset bulb is produced for each scapigerous plant, in which the bulb develops just to the side of the scape (hence the name). Central bulbs form only in non-scapigerous plants and are central to the main axis. Both bulb types germinate in fall and produce several new hardshell bulbs the following spring.
Just like domesticated garlic, hardshell bulbs (you might call them cloves in garden lingo) are produced immediately adjacent to the original bulb. Plants normally produce 1 to 6 hardshell bulbs per season. New hardshell bulbs are fully formed in early spring. Hardshell bulbs can sprout the following fall, however, only 20 to 40% of hardshell bulbs germinate the first year while the rest lie dormant up to 6 years.
Wild garlic does not have a spreading root system, and thus does not spread rapidly throughout fields. Dig up a clump of wild garlic foliage and you will find an assortment of bulbs and shallow roots. The primary mechanism by which hardshell bulbs are dispersed throughout a production field is via tillage equipment during the summer.
Wild garlic life cycle
Research from other parts of the country has documented wild garlic’s life cycle. Clumps of foliage emerge from bulbs, bulblets, or seed in September. Plants continue to grow vegetatively throughout late fall, winter, and early spring. Additional underground bulbs are formed in early spring (March). Seed and aerial bulblets are formed on flowering scapes in May and June, then plants die and wither away by mid-June.
To make more effective control recommendations for Oregon nurserymen, it was necessary to determine a precise date at which wild garlic produces new bulbs in the spring. Working with a local nursery, we dug wild garlic plants every two weeks for an entire winter and examined the progress of new bulb formation. We determined that new bulb formation in Oregon’s Willamette Valley occurs mid-March. In Figure 4 notice the bulb swelling to one side. By exerting pressure with my index finger, the immature bulblet was detached from the mother bulb. Undisturbed, it may have taken several more weeks for this new bulb to fully mature and release from the mother bulb. Nonetheless, at this stage herbicide applications may be too late to prevent the next generation of bulbs from forming.
New bulbs are in the final stages of development at the same time red maple (Acer rubrum) is flowering. Herbicide applications should occur prior to this, with a final application no later than when red maple begins blooming. Use established landscape trees as indicator plants instead of nursery stock. Trees still in nursery production can flower at odd times due to disrupted biological clocks in the quasi-natural ecosystems of nurseries.
The use of red maples to predict the production of wild garlic bulbs is an example of a phenological indicator. Phenological indicators are common temperature-dependent biological events (plant flowering, insect emergence, bud break, etc.) that are used to predict another event such as wild garlic bulb formation. Phenological indicators are useful and reliable tools for timing farm operations.
Wild garlic control
Kill wild garlic plants throughout fall, winter and early spring before plants can generate the next generation of bulbs in March.
Hoeing throughout winter or early spring will prevent development of new underground bulbs. This may be difficult with wet Oregon winters. If hoeing is not an option, 2,4-D applied before plants are 8 inches tall also provides effective control. Use caution when applying 2,4-D near nursery stock. Amine formulations of 2,4-D are safer (less volatile) then ester formulations. Make sure all herbicides are labeled for the site at which they are being applied.
Wild garlic bulbs can persist dormant in soil for 6 years. Nothing sprayed above ground can kill dormant bulbs beneath the soil surface. Complete control in a field infested with wild garlic cannot occur in a single year. Persistent management for at least 3 or 4 years (maybe as many as 6 years) is necessary to obtain complete control.
The overall concept in wild garlic control is simple: kill existing plants before they can produce the next generation and ultimately you will deplete the soil of this weed. Wild garlic control in practice is not quite so easy. If it were, I wouldn’t be writing about it and you wouldn’t be concerned about it. Wild garlic control is difficult and will require planning and persistence by the pest management supervisor at your nursery. Nonetheless, its biology and predictable timing of new bulb formation gives you an opportunity for control.
Disclaimer: This article is for educational purposes only. Mention of a specific product should not be interpreted as an endorsement, nor should failure to mention a product be considered a criticism. Always read the product label prior to using any herbicide.
Wild Garlic & Wild Onion
Wild garlic (Allium vineale) and wild onion (Allium canadense) are winter perennials, with wild garlic being predominant in South Carolina. They emerge in late fall from underground bulbs and grow through the winter and spring. In late spring, aerial bulblets are formed and the plants die back in early summer. The underground bulbs can persist in the soil for several years. While both have thin, green, waxy leaves, those of wild garlic are round and hollow, while those of wild onion are flat and solid.
Wild garlic plants (Allium vineale).
A cluster of wild garlic bulbs (Allium vineale).
Pulling: With a small number of weeds, pulling, though difficult, is an option. It is easier to pull up large groups of bulbs when the soil is moist. However, it’s likely that bulbs or bulblets will be left in the ground and new leaves will later re-emerge. For best results, dig them out with a thin trowel.
Mowing: Mowing will not kill wild garlic or wild onions. However, regular mowing can weaken plants and prevent them from setting seed.
Chemical: Unfortunately, there are no preemergence herbicides that will control wild onion or wild garlic. They must be treated with a postemergence herbicide, and persistence is the key. Plants will need to be sprayed more than once and for more than one season. One characteristic that makes control difficult is that both have a thin, glossy leaf to which herbicides don’t readily adhere. Unlike most weeds, mowing wild garlic or wild onion immediately before applying an herbicide may improve uptake. After application, do not mow for at least two weeks.
Timing of Sprays: Treat wild garlic and wild onion in November and again in late winter or early spring (February or early March) before these plants can produce the next generation of bulbs. However, be careful not to apply most weed killers onto centipedegrass or St. Augustinegrass during their spring green up period. Inspect the lawn again in the spring and the next fall, and treat if necessary.
Recommended Herbicides: Imazaquin, the active ingredient in Image Nutsedge Killer, will provide control for wild garlic and wild onion. This product should not be used on fescue and should not be applied to warm season turf during green up in spring. Wait at least 1-½ months after treatment before reseeding, winter overseeding or plugging lawns. This product is not for use on newly planted lawns, nor on winter over-seeded lawns with annual ryegrass.
Three-way broadleaf herbicides containing 2,4-D, dicamba, and mecoprop (MCPP) will provide control of wild garlic and wild onion with repeat applications. Examples of three-way herbicides for residential lawns in homeowner sizes are:
- Ferti-lome Weed-Out Lawn Weed Killer – Contains Trimec® Concentrate
- Southern Ag Lawn Weed Killer with Trimec® Concentrate
- Bayer Advanced Southern Weed Killer for Lawns Concentrate; + RTS
- Spectracide Weed Stop for Lawns Concentrate; + RTS
- Bonide Weed Beater – Lawn Weed Killer Concentrate
- Ortho Weed B Gon Weed Killer for Lawns Concentrate; + RTS
These products can be used safely on most turfgrasses, but reduced rates are recommended when applying to St. Augustinegrass or centipedegrass. Apply during November, very early spring, and again the next November for best control. Do not apply these herbicides during the spring green up of warm season turfgrasses, or over the root zone of nearby ornamental trees and shrubs. Do not apply these products to newly seeded grasses until well established (after the third mowing). Treated areas may be reseeded three to four weeks after application. Always check the product label for rate of application and to determine that it is safe for use on your species of turfgrass.
Celsius WG Herbicide, which contains thiencarbazone, iodosulfuron, and dicamba, will control wild garlic, especially if applied when the average daily temperatures are over 60° F. Apply in the fall and again 2 to 4 weeks later. The addition of a non-ionic surfactant, such as Southern Ag Surfactant for Herbicides, will increase control. Celsius is selective to control many broadleaf weeds & several grass weeds in all four of the common warm season turfgrasses, but cannot be used on a fescue lawn.
Imazaquin, as in Image Kills Nutsedge Concentrate or RTS, maybe used on warm season lawns for wild garlic and wild onion control. Do not apply to warm season turfgrass during the spring green-up of the lawn. It is not for use on fescue lawns & do not apply to St. Augustine lawns during the winter.
For Landscape professionals Metsulfuron, such as in Quali-Pro MSM 2500 Herbicide and Manor Herbicide give very good control of wild garlic & wild onions in bermuda, centipede, St. Augustine, and zoysia lawns. Quali-Pro Fahrenheit Herbicide also contains metsulfuron along with dicamba. For these three professional products, a non-ionic surfactant, such as Southern Ag Surfactant for Herbicides or Hi-Yield Spreader Sticker Non-ionic Surfactant, is required at 2 teaspoons per gallon of spray mix for best control. A non-ionic surfactant will help the herbicide adhere to the leaves for increased penetration, but many temporarily cause yellowing of the turfgrass. Blindside herbicide also contains metsulfuron along with sulfentrazone. Apply metsulfuron products to lawn at least one year old and when temperatures are below 85 °F.
Do not apply metsulfuron to a lawn if over-seeded with annual ryegrass or over-seed for 8 weeks after application. Do not plant woody ornamentals in treated areas for one year after application of metsulfuron. Do not apply metsulfuron herbicides within two times the width of the drip line of desirable hardwood trees.
Glyphosate is a nonselective herbicide that will also provide control of wild garlic and wild onion. If you are unable to prevent glyphosate from getting on desired actively growing grasses, a selective herbicide should be used. To avoid harming the turfgrass, apply glyphosate during winter, but only to bermudagrass once the lawn is completely dormant. However, during mild winters, the turfgrass may not be completely dormant. Examples of glyphosate products in homeowner sizes are:
- Roundup Original Concentrate,
- Roundup Pro Herbicide,
- Martin’s Eraser Systemic Weed & Grass Killer,
- Quick Kill Grass & Weed Killer,
- Bonide Kleenup Weed & Grass Killer 41% Super Concentrate,
- Hi-Yield Super Concentrate,
- Maxide Super Concentrate 41% Weed & Grass Killer,
- Super Concentrate Killzall Weed & Grass Killer,
- Tiger Brand Quick Kill Concentrate,
- Ultra Kill Weed & Grass Killer Concentrate,
- Gordon’s Groundwork Concentrate 50% Super Weed & Grass Killer,
- Zep Enforcer Weed Defeat III,
- Eliminator Weed & Grass Killer Super Concentrate,
- Monterey Remuda Full Strength 41% Glyphosate,
- Knock Out Weed & Grass Killer Super Concentrate,
- Southern States Grass & Weed Killer Concentrate II,
- Total Kill Pro Weed & Grass Killer Herbicide,
- Ace Concentrate Weed & Grass Killer.
There are a number of weed control options available to treat wild garlic. In addition to traditional weedkillers there are now also a range of more natural alternatives.
Contact weedkillers will burn and kill the foliage, but will have no effect on the bulbs. Constant spraying whenever leaves are present may weaken and kill them in time, although their foliage isn’t around for very long.
A systemic weedkiller, which is absorbed by the leaves, then moves down to the bulbs to kill them.
To ensure the weedkiller works effectively:
- Spray the leaves when the plants are growing actively.
- The larger the leaf area present, the greater the amount of weedkiller that can be absorbed. So don’t bother spraying when the growth first emerges through the soil – wait until the leaves grow larger.
- The most effective time is just before flowering.
- Use a fine spray to thoroughly coat the leaves in small droplets.
- Don’t spray when the sun is fully out. Ideally spray in the evening to prevent the spray evaporating and to give maximum time for the spray to be absorbed.
- One application of weedkiller probably won’t completely kill wild garlic. You may need to make repeated applications over several years.
Most contact weedkillers are total weedkillers – that is they will damage or kill any plants whose leaves they are sprayed on. Make sure you keep the spray off wanted plants – including lawns – and, if necessary protect plants by covering with polythene or similar when spraying.
Use weedkillers safely. Always read the label and product information before use.