Street smarts for trees: Bigger pits mean better growth

Backyard Q&A

In The Garden

November 02, 2003|By Dennis Bishop | Dennis Bishop,Special to the Sun

We have several empty tree pits in front of our row home that we would like to plant trees in, but they are only 3 feet square. Is this large enough to plant a tree?

Ideally, all street trees would be planted in median strips the length of each city block. However, we rarely have that situation in Baltimore, so we need to do the best we can with tree pits.

Yes, a tree pit that size is large enough to plant a tree in, but trees are better off when they are planted in larger pits. Larger pits provide more soil for young trees to get established and provide room for growth as the tree matures. You might wish to contact the city to see if your tree pits can be enlarged. This would involve cutting and removing more concrete from the sidewalk. While this is not a major job, it might take some time to schedule the work, and you might be required to pay for it. In the long term, it will be worth the expense.

If you do not enlarge the pit, consider planting a smaller tree, such as a Kwanzan cherry. They seem to grow very well here in the smaller pits.

We have a row of leatherleaf viburnums in our back yard that were sheared into a formal hedge by the previous owners. We would like to let them grow more naturally. What should we do?

Viburnums tend to have upright canes, with strong lateral branches at 90 angles from the canes. This makes them very hard to properly prune. When the plants are headed back or sheared, they develop tufts of branches at the cutting points. This destroys their natural beauty and makes them very difficult to naturally prune later on. Thinning works on young viburnums, but it is not always successful on overgrown plants.

Sometimes, it is best to cut them back very hard and let them regenerate all new canes from the base (I am not sure if I would do this with a plant like Korean spice viburnum, but I would certainly try it on leatherleaf viburnum).

The best time to cut them back is in late winter or very early spring. If you choose this method, cut them back to about 6 inches from the ground. As the spring unfolds, the plants will respond by generating a lot of new canes. These canes can be thinned in late spring.


1. It is time to get bulbs in the ground. Bulbs planted now will have plenty of time to get established before blooming next spring.

2. Are you planting trees this fall? Be sure to select a tree that is appropriate to the site. Large trees like red maples should not be planted under power lines.

3. Many evergreen trees naturally drop their older needles at this time of year. Let the needles fall as mulch for the tree, or gather them to mulch annual or perennial flowerbeds.

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

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