Q • I have an abundance of wild onions mixed with my English ivy. How can I get rid of the onions? Picking them out does not work.
A • If you just pull the tops once or twice as an afterthought, you won’t have any success eliminating wild garlic (onion). The bulbs remain deep in the soil and will eventually resprout due to stored energy.
If you’re persistent enough to immediately remove the foliage each time it sprouts, with the goal in mind of keeping the plant virtually defoliated for several years running, eventually it will run out of energy. I have successfully eliminated wild garlic from vegetable beds by hand digging, albeit only after sieving the shovelfuls of soil containing the bulbs through a quarter-inch hardware cloth mesh and picking out the roots and bulbs individually. Tedious and time consuming as you can imagine, and a solution with limited effectiveness due to competing roots of nearby trees and shrubs, but it can work provided you make a thorough effort.
On the other hand, wild onions are a spring ephemeral plant, and their leaves die back and disappear underground with the onset of hot weather, not to be seen again until late the following winter or early spring. So the laissez-faire gardener can turn a cheek and get on with the other business.
Herbicides are not very effective either, frequently requiring several applications on an annual basis. I am not aware of any product that would selectively control only wild garlic and not damage your English ivy, so you have to be very careful to apply material only to its foliage. If you wish to go this route, products containing 2,4-D with dicamba are labeled for the control of wild garlic (onion). Be sure to follow the label directions, and be aware that 2,4- D plus dicamba can be taken up by the roots of nearby trees, shrubs, vines and other perennials, resulting in injury or death of the plant.
Write to Chip Tynan of the Missouri Botanical Garden at email@example.com or Horticultural Answer Service, 4344 Shaw Boulevard, St. Louis, 63110
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