In the Garden with Pat Rubin

Bee garden writer Pat Rubin writes about everything that grows, from flowers and trees to vegetables and lawns. Pat volunteered for several years as a Placer County Master Gardener and has written about gardening for many national and regional publications. In addition to gardening, she spends time raising and showing miniature horses and miniature donkeys.

In the Garden will include news, events, advice and other gardening tidbits. Pat will also answer reader questions.

• Ask a question

« Repotting a gardenia | In the Garden front page | Putting seedlings outdoors »

March 26, 2008

Pesky wild onion

Q: Every Spring, my yard is inundated with wild onion. It’s invaded the ground cover, shrubs, etc, but doesn’t seem to be established in any of the immediate neighbors’ yards. I’ve tried hand pulling, but it’s a relentless task with moderate results. Do you have any suggestion that might help?
Mark Marvelli, Sacramento

A: Wild onion, Allium canadensi, is a formidable opponent. Many gardeners have let it loose without realizing until too late it’s a thug in disguise.

At first it seems so innocent, even desirable and beautiful. What a wonderful ground-cover, you might say to yourself. It comes up in the spring, makes a lush, grassy carpet, and then blooms profusely.

And then you realize it’s out to take over the world. Suddenly those bright green strappy leaves are no longer beautiful or desirable.

It’s possible to eradicate wild onion from the garden, but it takes patience, perseverance and time, perhaps several years.

Pulling them out often breaks the leaves off at bulb or ground level, and lets the bulb live to sprout again. Better to dig them out.

You can mow them, and it will weaken the plants, but would take years to kill them, and you’d have to be meticulous about keeping them mowed so no bulb got a chance to grow and bloom.

The advantage to mowing and pulling, though, is that you’ll keep the plants from setting seed, which sprouts and grows exceedingly easily.

The third option is spraying the wild onion with an herbicide. But even spraying is difficult because the leaves are slick, almost glossy, and water runs right off of them, so you can imagine it’s hard to get the herbicide to stick. Add a spreader/sticker, available at nurseries and garden centers, to the herbicide mix.

The best offense is to combine all three. Spray the wild onion, let the spray have some time to take effect, and also mow, pull or dig them out. Then spray again.

The University of Clemson says spray in March and November (April isn’t too late), and recommends chemical treatments like Image, Roundup, Eraser, Trimec Southern or Bayer Advanced Southern Weed Killer for Lawns. Be sure to read the label since some of these herbicides are nonselective, which means they’ll kill any other plants they come in contact with, too.

Ask a question

Please use the form below to submit your question. Because there is a 100-word limit for questions, a word counter is located directly beneath the box where you enter the your question.