Wisteria takes persistence to control

June 27, 2018
  • By Walter Reeves
  • For the AJC
The pretty flowers of wisteria belie its aggressive nature. WALTER REEVES

Q: Wisteria has covered several trees in my yard. Is there a way to get it under control? Cynthia Parker, email

A: Wisteria is tough to control by any means. Earth moving machines can do the job quickly but you might lose your trees. Alternatively, if you have the time to devote, you can starve the roots by constantly killing the foliage above ground. This technique may take two years to get acceptable control. First, sever all major vines from their roots at ground level. Spray glyphosate (Roundup, etc) onto the stumps immediately. The chemical will be sucked back into the root system for a small distance but I’m positive it won’t kill the entire root system.

If you have nearby too many small shoots to chop them all, spray them with glyphosate (Roundup, etc) or triclopyr (Brush-b-Gon, etc) herbicides. Canvass the area two months later and remove or spray any greenery you find. You’ll probably have new wisteria sprouts next spring and summer that you’ll have to hit once again.

Q: Typically I aerate, fertilize, and apply a long-lasting weed control to my lawn. Do you think the effects of each activity would be less than optimal if they are done too close together? Al Ciraldo, email

A: I think this is fine for a spring sequence, with a small wait between the last two. Aerate the lawn first, which gives the grass roots good growing conditions. Soon afterward, apply fertilizer to stimulate strong root and shoot growth. Wait until after a rain or irrigation and put down the weed killer. If you’ve chosen your weed-control product correctly, the newly emerged weeds will take up the herbicide and will die quickly.

Q: How do I take cuttings from a Confederate rose, Hibiscus mutabilis, to root? When is best time? James Bullard, email

A: I do it in fall so I can give away rooted cuttings in spring but the plant doesn’t much care about timing. Once the stem has hardened (turned from bright green to gray/brown) it is ready to make new roots. If your plant stems are six feet tall, you can usually make several 8-inch cuttings from the hardened part. Include at least one leaf at the top of each cutting. Immerse the lower half of each one in water. A small bucket or large vase works well for this. Situate the cuttings in bright shade and they’ll have roots in four weeks.

Q: I have a small vegetable garden in which I plant tomatoes. I’m concerned about repeatedly planting tomatoes there year after year. The garden isn’t big enough to rotate plants. Lloyd Farr, email

A: You have a problem faced by many gardeners with a small area in which to work. I think you’ll just have to be vigilant about controlling weeds and insects so their population can’t build up. Always remove and destroy diseased leaves. Aim to provide for your tomatoes a sandy loam soil that does not remain soggy. If you are reasonably attentive to management details I think you can successfully grow tomatoes in the same spot for several years.