Digging In: Plants That Dress Up Walls

By Scott Aker
Special to The Washington Post
Thursday, October 15, 2009

Q I have a 40-foot planter wall along the sidewalk with an unobstructed eastern exposure, varying in height from two to five feet. Could you recommend plants that would cascade over the wall? I'd like perennials.

A With so long a wall, try a mix of annuals, perennials and woody plants. You could choose golden Hakone grass for the lower parts of the wall, and prostrate rosemary would be lovely on some of the higher sections. A few plants of winter jasmine will give a surge of early spring color to the planting. Add some trailing annuals such as standard nasturtiums (avoid the bushy varieties and plant seeds of old-fashioned trailing types), cascading petunias and lobelia to give some splashes of color in the summer.

Neighbors in our cul-de-sac allow their dog to roam freely, which then fouls my lawn and garden beds. My husband says we should clean up the mess and say nothing to maintain a civil relationship. I am angry. Is there some way to stop this without harming the dog or the environment?

Your neighbor needs to take responsibility for his pooch's poop, not only to make life pleasant for you but to keep contaminants out of waterways.

There is no substance or material, other than a fence, that will prevent this problem. You should approach your neighbors in a pleasant way to make them aware of the issue and request a solution. First, make sure the waste is not from another dog. You might also contact your local animal control officer for advice on handling this situation diplomatically.

We have two 20-year-old lilac bushes that bloom beautifully with little care. Lately, I've noticed holes that suggest borers in the trunks. How do I fix this?

You can keep lilac borers under control by pruning the oldest trunks to the ground every few years. New growth will spring from the crown of the shrub, and since the borers feed only on the older wood, they will be unable to find branches that they can infest. This kind of renewal pruning will help keep your lilac more vigorous and make the panicles of flowers larger. Wait until May to prune, just after the flowers have faded.

Scott Aker is a horticulturist at the U.S. National Arboretum.


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