Growing pains and pesky pests

The Washington Post’s gardening columnist Adrian Higgins answers questions about pest infestations, invasive flowers, pruning your unruly azaleas.

QWe have a number of potted plants that we bring in for the winter and put back outside when it warms up in the spring. This year we noticed that several, including one we leave indoors year round, have been infested with ants. Is there any way to get rid of the ants without harming the plants?

AAnts are usually an indication of another pest, maybe aphids or more likely mealybugs. The ants farm these creatures for their honeydew secretions. Ants don’t harm plants, but mealybugs do. Before setting the pots outside, I would dunk them in the bathtub for a good hour or two, i.e. set the pots in a few inches of water until the soil is totally saturated. Check for mealybugs on the top growth. You can remove them with alcohol on cotton swabs. If there is a bad infestation, it’s better to bag the plant and start again.

QI know wild violets are native, but they go where I don’t want them to. Do you pull, or just enjoy the beautiful blue flowers?

AThe common blue violet does look pretty but is astonishingly invasive. There are two basic approaches. The first is to take a knife or a fishtail weeder and pry up the submerged rhizome from which each tuft grows. The other approach is to declare them beautiful and do something else with your time.

QI have overgrown azalea bushes (some 10-plus feet/3-plus metres high), that previous owners used bungee cords and poles to hold up instead of pruning. An arborist suggested we trim them way back but warned that we might lose the next year’s blooms. They also quoted several thousand to trim them. Any advice on how to start if we try to prune them ourselves?

AAzaleas take well to deft pruning. Right after blooming is an excellent time to prune them, which you can do by taking back whole stems to where they join other branches. With some careful consideration and practice, you can reduce the bulk of the shrub but also open it up. You will need a long-sleeve shirt, thick work gloves, a quality pair of hand pruners and sharp lopping shears, and maybe a sturdy step ladder.

QI am a veggie gardener, and in the past two years, cucumber beetles took out 20 plants. What can I do this year?

AThe key is to stay on top of them, to handpick them early before populations build up.