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.
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.