Fall is fast approaching and with the cool weather comes the emergence of cool season weeds. Two of the worst are wild onion (Allium canadense) and wild garlic (Allium vineale). Yes, they are actually two different weeds. As is evident by the Latin names, they are closely related. Both plants are edible with very strong flavors.
There are a few things that make it easy to tell these two weeds apart. First, the wild onion has flat, solid leaves, while wild garlic has round, hollow leaves. Second, the leaves of the wild onion all emerge from the soil line or base of the plant, while the leaves of wild garlic tend to be formed higher on the stem or above the soil line. Lastly, the wild onion has a net like or reticulated membrane surrounding the bulb that the wild garlic does not have.
Wild onion is a native plant, which reproduces by seed. Wild garlic was imported from Europe. One reason wild garlic is more aggressive is that it produces little bulbs called bulblets from the flowers. Bulblets are tiny plants ready to start growing.
Hand pulling is often an ineffective method of control. The bulb anchors the plant in the soil causing the leaves to break off at ground level. Digging is more effective, but can be quite time consuming. Chemical control is another method. In warm season turf such as bermudagrass, zoysiagrass, centipedegrass, and St. Augustinegrass, chemicals containing the active ingredient imazaquin (Image 70DG) can be used. Read the label on this product as it has been shown to cause some damage to certain ornamental plants. In fescue, bluegrass, bermudagrass, and zoysiagrass, chemicals with the active ingredient 2-4D amine may be used.
The leaves of wild garlic and wild onion have an outer waxy layer. The use of a surfactant will aid in holding the chemical on the leaves where it can be absorbed into the plants. One application will not be enough to completely kill these weeds. Some studies have shown it may take two years to completely eliminate these from turf.
For more information on winter weed control, contact your local office of North Carolina Cooperative Extension or find us on the web at http://www.ces.ncsu.edu/.
Shawn Banks is the Consumer Horticulture Agent with the NC Cooperative Extension Service in Johnston County. You may reach him at firstname.lastname@example.org.