Falling Berries, Doggy Patches and Heavenly Bamboo: Time for Early Spring Queries

It's time for your early spring gardening questions.

Q: I have a female and male Ilex verticillata. Each year the female sets berries and they fall off. What might be wrong? -- Lynn

A: Winterberry hollies ( Ilex verticillata) lose their berries for several reasons. One, the plants might be too dry. Winterberry hollies like moist to wet soil, and the berries begin to form in August, usually the driest time in this region. Don't let them dry out. Temperature swings are another potential cause. If berries freeze at night and thaw quickly, they'll drop prematurely. Protect them from morning sun, especially if they're near reflective surfaces, like paving or siding. Finally, you may have lost them to hungry birds.

In your column on dogs and yards, you didn't address the problem of dogs urinating on trees and lawns. This sometimes kills the grass and leaves brown spots in the lawn. How can I get the grass to grow again where dogs urinate? -- Bob M.

First, rake the burned-out grass with a leaf rake. Wash the salts from the urine into the soil with a garden hose, and reseed burned areas. Sprinkle a little compost over the spot to hold moisture and keep the seed in place. Lightly spray the areas with water daily until the seeds germinate. When grass begins to show green, water more deeply and less often, once or twice a week, until it needs mowing.

We plan to plant nandina but want to avoid plants that would harm our cairn terrier. In a previous column, you wrote that nandina was toxic. We checked cybercanine.com and other sites, and nandina was not listed. Where did you learn that it is toxic?

-- Jan and John S.

From the Web site of the American Society for the Prevention of Cruelty to Animals, at http://www.aspca.org/site/PageServer?pagename=pro_apcc_toxic_heavenlybamboo. You will find nandina listed by its common name, heavenly bamboo. But plants with toxic parts can harm pets only if they ingest them. If your pet doesn't gnaw on plants, it will be fine.

I have problems with bare spots under pin oaks and a willow oak, all very large trees. Green moss is replacing the lawn that was growing under them. Why? -- Harry

Shade is the primary reason lawn yields to moss, which is better adapted to shallow rooting and moist shade. To encourage lawn under dense shade trees, allow as much dappled sun through the canopies as possible, which could require a cleanout pruning by a professional arborist. Lower limbs should reach no lower than eight to 10 feet above ground level. That could mean elevating them 12 to 15 feet or higher up the trunk. Cut limbs all the way to the trunk, leaving the branch collar (the widened portion at the base of the branch).

This spring our lawn is inundated with mounds of hills (like anthills) with a hole in the top. We spotted and captured what appeared to be a bee coming out of one of the holes. What can be done to prevent this from happening next spring? What can be done now?

-- Paul and Maggie