March 11, 2015

What can be done about wild onion & garlic?

The presence of wild onion and wild garlic in lawns during early spring brings many comments from our customers. Both are cool season crops, so they are a nuisance in the lawn in both spring and fall. They suffer in hotter weather, so they tend not to be much of a problem for lawns in the midsummer.

The control of either wild onion or wild garlic is very difficult, because the plants have evolved to have a great resistance to chemical controls. First, they have a linear leaf, so sprays have a tendency not to stick to them like they would the typical broadleaf weed. They also have a thick waxy leaf coating or cuticle which resists the penetration and absorption of herbicides. Finally, they reproduce rapidly by producing many above ground and below ground bulblets, flowers, and a central bulb.

The plants are monocots, as are grasses, but they have shown some limited susceptibility to the herbicides which many people use to control broadleaf weeds in turfgrass. A combination of 2, 4-D, MCPP, and Dicamba have shown some control over time with these weeds.

This chemical control can be enhanced by using some mechanical method to scrape or damage the waxy cuticle prior to chemical sprays. This could be accomplished by the labor intensive task of rubbing sandpaper over the leaves prior to the spraying.

Two sprayings per year for wild onion or wild garlic is preferred. Best control would be found when the plant is most actively growing. Therefore, a spring application and a fall application of weedkiller will produce the best results.

A very important step in avoiding any weed problem, is to provide the best possible growing conditions for the desired crop. This means then that proper consideration should be given to frequent mowing at a relatively high mower height, proper fertilization with the bulk of nutrition being added in the fall, watering during periods of drought, controlling of pests, and regular renovation including dethatching, aeration and seeding.