Proper pruning of pines and spruces

Backyard Q&A

June 14, 1998

Q.I planted a row of 10 white pines and spruces several years ago and want to begin pruning and training them so they will develop into large, healthy trees. How do I start?

A.Start with a pair of sharp hand pruners. Spruces and pines produce new growth ("candles") each spring at the ends of their branches. The candles are compact, elongated and light-green in color. Pruning back the candles halfway will force two new shoots to emerge from the cut. This will cause the trees to fill out more quickly. Removing the candles entirely will slow the trees' growth.

Entire branches can be pruned back to maintain a desirable shape. But don't prune back the leader (main trunk); you'll ruin the shape.

Q. Not long after I transplanted my tomatoes, I noticed brown spots on the lower leaves. The spots seem to be growing and spreading. Does this sound like a disease? Where does it come from?

A.Several fungal leaf-spot diseases affect tomato plants, including septoria, gray leaf spot and early blight. These diseases overwinter in the soil and on tomato-plant debris left in the garden. Fungal spores splash up from the soil when the plant is watered and infect the lower leaves.

These diseases also come in on purchased transplants. Early blight is the more serious disease and can defoliate plants quickly during wet, humid summers. The brown spots of early blight have concentric rings that can be seen upon close inspection. To control the disease: 1) snip off and discard lower leaves with symptoms, 2) mulch heavily with grass clippings, straw or newspaper to keep soil from splashing onto leaves, 3) water the root system, not the foliage and 4) if infection is severe, apply an appropriate fungicide.

Garden tips are provided by the Home and Garden Information Center of the Cooperative Extension Service of the University of Maryland. For more information on these questions, or if you have questions of your own, call 800-342-2507, or visit its Web site at http://www.agnr.umd.edu/users/hgic.

THIS WEEK'S CHECKLIST

* Closely examine the lower stems of wilted squash plants for squash vine borer damage. Carefully slit the affected stems with a razor blade and remove the borers.

* Monitor evergreen trees and shrubs, especially spruces, for signs of newly hatched bagworm larvae (you'll see very small bags attached to needles and stems.) Spray with B.t., a microbial insecticide, to control larvae.

* Keep pepper, eggplant and tomato plants well supported with cages or stakes.

Pub Date: 6/14/98

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