To quiet the roar of traffic, try planting a spruce screen


In the Garden

November 09, 2003|By Dennis Bishop | Dennis Bishop,SPECIAL TO THE SUN

We would like to plant a tall evergreen screen to block the sight and sound of road traffic. Would you recommend spruce, pine or hemlock trees?

If you want a thick evergreen screen, spruce would be the best choice for our area.

The Canadian hemlock (Tsuga canadensis) is a beautiful plant; however, it is being attacked throughout the Northeast by a small insect called the hemlock wooly adelgid. The infestation is severe, and these trees are no longer recommended for planting in our area.

There are several pines that grow well in our area, but pine trees naturally lose their lower branches over time. They eventually become canopy trees and in the long term do not make good screens.

That leaves spruce. The two spruces you are most likely to find in our area are Norway spruce (Picea abies) and Colorado spruce (Picea pungens). The Norway spruce is more adaptable to soils and sunlight, and it grows faster than Colorado spruce. It is medium to dark green in color. On the other hand, the Colorado spruce is denser than the Norway spruce and will probably form a better barrier. The color of Colorado spruce varies within the species and among the cultivars from dull blue green to bright powder blue. Either will work.

I purchased mums this fall in 8-inch containers to plant in pots on my porch. How can I save them to use again next year?

Most of the mums sold in garden centers are hardy mums that will winter over in Baltimore. As soon as the mums finish blooming, remove them from the pots and temporarily plant them in your yard (heel them in). They should be planted at ground level and covered with 1 to 2 inches of mulch. Do not overdo the mulch.

In the spring, as soon as new growth begins, dig the mums up, divide them and replant them. Each container can probably be divided into five or six pieces, but this will vary from plant to plant. Because the centers of mum plants tend to die out, I would take the divisions from the edges of the clump and discard the center. These divisions can be replanted in the ground as part of a flower border, or they can be replanted into pots.


1. Select new trees carefully from nurseries and garden centers. Do not purchase trees that have broken root balls or damaged bark.

2. Are you hauling plants from the nursery in an open truck or trunk? Be sure to cover your plants with a tarp. Drying winds on the trip home can damage uncovered plants.

3. Ticks remain active as long as temperatures exceed 45 degrees to 50 degrees. Be sure to check yourself and others for ticks when hiking on mild fall days.

Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (8 a.m. to 1 p.m. Monday through Friday) at 800-342-2507. You also can e-mail questions, order publications and diagnose plant problems by visiting the Web site

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