Ron Kujawski: Treating winter burn symptoms


You know what burns me about rhododendrons -- winter burn. Now is time to inspect rhododendrons and other broad-leaved evergreens, such as boxwoods, hollies, and mountain laurels for symptoms of winter burn.

Winter burn occurs when soil is frozen or very dry and plant roots cannot take up water to replace that evaporated from the leaves. Evergreens in sunny and windy locations are most prone to winter burn.

As temperatures warm, the symptoms should become more visible. Symptoms include browning of the tips and edges of leaves, and, in severe cases, dieback of twigs.

If only the leaves are affected, breathe a sigh of relief because the plant will send out new shoots and leaves this spring. If the shoot tips are dead, cut back the twigs to live tissue.

If uncertain if a twig is dead or alive, scratch the bark with your thumbnail. If the tissue beneath the bark is brown, that section of the twig is dead. If the tissue is white or pale green, the twig is still alive and no pruning is needed. Breathe another sigh of relief.

Breathe another sigh of relief that the slowly improving weather is allowing us to get on with these tasks:

• Prune plants used in hedges so that their tops are narrower than their bottoms. If the tops are wider than the bottoms, the bottom branches are shaded and will typically drop their leaves or needles, resulting in bare bottoms. Bare bottoms may be acceptable at some beaches but are not very becoming on plants in hedges.

• Wait until grass is a little more than three inches tall before the first mowing. Then cut the lawn back to a height of no less than 2 1/2 to 3 inches. Cutting grass at this seemingly tall level will encourage deeper root development and help prevent weed problems. Tall grass shades the soil and keeps it cool; these are conditions which discourage germination of crabgrass seed.

• Work in plenty of organic matter (compost, well-rotted manure, peat moss) to a depth of 8 to 12 inches prior to planting grapes, strawberries, raspberries, blueberries, asparagus, and rhubarb. This is a good time to plant these permanent crops.

• Plant potatoes. Typically, potatoes are planted from pieces of so-called seed potatoes or from small, whole potatoes. Plant the seed pieces or small potatoes about 10 inches apart in a furrow that is 4 inches deep and then cover with a few inches of soil. When new shoots are 5 inches tall, begin pulling soil up and around, but not over the stems.

• Transplant tomatoes, peppers, and eggplant from their seed flats into larger flats or into individual pots. They still have a long time to grow before setting out in the garden and will need a little extra breathing room now or they'll get leggy from overcrowding.

• Don't move seedlings of broccoli, lettuce, onions, and other cool season crops directly from indoors to the garden. Though these plants can tolerate cool temperatures and light frosts, they still need to be acclimated to the outdoors. This is easily done by moving seedlings to a cold frame for seven to 10 days prior to planting. Alternatively, move seedlings outdoors to a partially shaded place protected from wind. Start with an hour exposure the first day and then gradually increase their time outdoors over a period of 7 to 10 days before planting.

• Watch for the emergence of tent caterpillars. This is their time to set up camp and feed on the new leaves of cherries, crabapples, and apples. Applications of the naturally occurring bacterium, Bacillus thuringiensis (Bt), are effective if applied to the early stages of the caterpillars.

• Hug a Tree today. It's Arbor Day. That tree will breathe a sigh of relief that you're not cutting it down.


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