The Bay Gardener by Dr. Frank Gouin

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Give a Home to Cypress Trees

They’ll give you landscape appeal, valuable lumber and cute knees

Southern Marylanders can grow more species of plants than many of our neighbors to the north and west. This is due to the tempering effect of the Bay and our southern latitude. We are at the northernmost latitude for growing cypress trees, both bald and pond species. Calvert County has the largest cypress forest in the state.

Cypress trees grow on well-drained soils as well as in bogs and ponds. After they are well established, they can tolerate severe dry conditions. However, a cypress growing in boggy soil will develop differently from one growing in well-drained soils.

When grown in well-drained soil, both species of cypress will develop a typical trunk, slightly fluted at the base. The summer foliage is a lush green; fall foliage turns a brilliant rusty red. Every year I look forward to seeing its fall foliage.

In wet soil and bogs, the trunk of the trees near the ground will be buttressed and knees will develop from the surface roots. It will take 10 to 15 years after transplanting before the knees are noticeable. As the trees age, the knees enlarge in height and diameter.

The wood of cypress trees is valuable because it is resistant to rot and has a beautiful grain. It takes approximately 40 years to grow a cypress tree to marketable lumber size. The wood of the knees is a deep, chestnut-brown and is valued by artisans as it is easily shaped and polished.

Fighting mites and sooty mold

Q The azaleas, roses and crepe myrtle in our new home were attacked by mites, which I treated with periodic applications of soapy water, over and underneath the leaves. However, the crepe myrtle (and a shasta daisy) became covered in a thick, black sooty film over the branches and leaves. The daisy bloomed well, but the crepe myrtle had one weak bloom only and sparse leaves. This sooty film is still on my plants.

–Kimberly Hall, Millersville

A Sooty mold is a fungus released from feeding aphids and scale insects. I strongly suspect you have oak, tulip poplar or maple trees growing nearby that are infested with one or both of these insects.

As the insects feed, they excrete honeydew, a sugary residue that drifts down on your plants. The fungus grows on the honeydew. Control the insects, and you will control the fungus.

Horticultural soap only controls adult mites. Use horticultural oil or summer oil instead. The oils are safe and provide 100 percent control of adult mites, larvae and eggs.

If the sooty mold becomes so thick that it covers the leaves of your plants, it can injure them. I do not know of any fungicides that control this fungus effectively. Spraying the plants with a strong stream of water is the best means of reducing the mold.