Q: I have cactus all over my back yard. I am guessing that a long time ago someone dumped a “dead” pot of pricklypear cactus out back and it rooted. Then, every time someone mowed the lawn, the cactus pieces rooted in place. I now have over two acres of prickly lawn. My Girl Scout troop and my own son and daughter have to put on combat gear to play outside. What can I do to get rid of it?

A: Pricklypear cactus can survive years of drought because its waxy skin inhibits moisture loss. The skin also prevents the absorption of weed killers. You’re not going to like my answer, because it is a lot of work, but here is the best advice from Dr. Tim Murphy, my weed specialist colleague.

1. Try again to dig up all the pieces. A good quality dandelion fork works well. This may take a few years.

2. If you can’t dig them up, cut each one at ground level and paint the stump with undiluted triclopyr (Brush B Gon(tm)).

3. Examine and improve your lawn maintenance practices. According to Dr. Murphy, pricklypear cactus usually thrives in poorly maintained turf. If you have a vigorous lawn grass growing with the cactus, the grass will shade and out-compete the stickery plant.