Not all beetles in your yard are emerald ash borers

Garden Q&A

  • This variety of hydrangea will bloom even on stems that died to the ground over the winter.
This variety of hydrangea will bloom even on stems that died… (Photo amp Text by Christine…)
June 06, 2014|By Ellen Nibali, For The Baltimore Sun

I found a shiny green bug in my yard, and I'm afraid it is the emerald ash borer that is killing ash trees in Maryland. What should I do about my ash tree?

The emerald ash borer beetle is rarely seen. It's about 1/2-inch long with a tapering silhouette. Recently, many people are confusing them with green tiger beetles. This voracious predator of other insects is 1/2- to 3/4-inch long, with an abdomen wider than the head and thorax and six white spots on the abdomen — a good guy in your landscape, though its powerful jaws can nip. For guidance on identifying emerald ash borers and symptoms, observing the quarantine on ash wood, and deciding on treatment of a valuable ash tree, go to

I'd been watering my new dogwood for 45 minutes a day like I was told to do, but I forgot the hose one day and watered for 50 minutes. It looks terrible. What can I do?

No plants should be watered on a rigid schedule. Rainfall varies; evaporation rates vary depending on temperatures and wind; soils vary in water-holding capacity; water pressure and hose size vary; and plant needs vary from season to season and as it grows. In the case of your dogwood, you received poor advice. It wasn't the five extra minutes of watering that did the damage. Dogwoods do not tolerate "wet feet" (standing in saturated soil for a long time). Some of its roots probably rotted. If it recovers, water it only during dry periods. Poke a finger or tool into the ground to see how dry it is, and don't water until the top inch or two of soil is dry. With our scattered showers in Maryland, the only way to know how much water your plants are getting is to have a rain gauge — any flat-bottomed container can work.

Does it matter that orange and black insects are eating my asparagus leaves, since we aren't harvesting the spears anymore?

Yes, it matters because those ferny asparagus leaves need to grow and store carbohydrates in the roots all summer to have the energy to produce spears for eating next spring. The asparagus beetles you see lay their eggs on spears in the spring. Both larvae and beetles consume asparagus foliage. Right now, knock the adults into a tub/bucket of soapy water. If damage is severe, use a neem, spinosad, or pyrethrum insecticide (all organic). In fall, cut down and destroy all asparagus foliage and nearby weeds where the adults will overwinter. Next spring, use row cover on the emerging spears to prevent egg-laying on them.

University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to its website at

Plant of the week

Reblooming bigleaf hydrangea

Hydrangea macrophylla remontant

Many mophead, or bigleaf, hydrangeas died to the ground this harsh winter. The happy news is that they usually regrow from the roots in a season. The bad news is that, in most cases, there will be no flowers this year, because older varieties bloom only on stems made the year before. Happily, around 2,000 nurseries introduced new hydrangeas that produce blooms on both new and old stems. Some varieties of "remontant," or reblooming, hydrangeas of note include "endless summer" and "blushing bride." If you prefer the flat blooms of a lace-cap type, go with "twist and shout."

—Christine Pfister McComas

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