ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Sunday, September 8, 1996 TAG: 9609100015
SECTION: HOMES PAGE: D-1 EDITION: METRO
COLUMN: Dear John
SOURCE: JOHN ARBOGAST
Residential as well as commercial horticulturists are familiar with the late-summer or early-fall announcement each year of All America Selection winners for the next growing season. Using AAS award winners is an excellent way to reduce pesticide applications and prevent problems.
To help you in garden and landscape planning, look for the red, white and blue AAS logo in mail-order catalogs and on packets of seed and bedding plants.
Zinnia lovers who have been dismayed in trying to control powdery mildew disease will enjoy growing Crystal White Zinnia (Z. angustifolia). This new annual variety was named the '97 AAS Bedding Plant Winner, which means that plants should be available from garden centers this spring in addition to being offered in some catalogs.
Crystal White provides pure white, daisy-like blooms nonstop through the growing season on plants that should grow to be about 10 inches by 10 inches. Gardeners should easily be able to raise this variety under stressful growing conditions, such as oppressive summer heat that can cause a lack of flowers in other annuals. Watering and occasional fertilization are the only maintenance needed to keep Crystal White plants thriving and flowering, because pinching and pruning are not required.
The two annual flowers that were named '97 AAS Flower Winners are Gypsy Baby's Breath, (Gypsophila muralis) and Prestige Scarlet Cockscomb, a new type of Multiflora Celosia cristata.
Folks who have seen baby's breath in floral arrangements know how light looking yet sturdy that this flower is. Gypsy has that same look, but the plants will only reach about 10 to 14 inches in height. They abundantly produce 1/4-inch-size pink blooms in a sunny location.
Prestige Scarlet should reach a medium height of 15 to 20 inches, producing an uninterrupted show of many 31/2-inch, deep scarlet, velvety cockscomb blooms. Excessive heat or periods of drought or flooding should not stop this new variety.
Tree news
Roanoke will host the Virginia Urban Forest Council's annual conference for '96 at the Airport Sheraton Inn Oct. 30-Nov. 1. On the first night of the conference, the International Society of Arboriculture, the certified arborist exam will be given. This will be the only credentials testing time for tree workers in 1996. Those interested in this exam should contact the ISA at 217-355-9411 or write to: ISA, Certification Program, P.O. Box GG, Savoy, Ill. 61874. Exam fees must be paid by Oct. 11, and the two self-study manuals should be ordered in ample time to prepare for this test. Folks with questions can call Bob Boeren with the Virginia Department of Forestry Salem Office at 387-5461.
Q: When is the best time to cut back and prune my small planting of black raspberries? V.W., Roanoke
A: Black raspberries should be summer-topped during the growing season when the young shoots are about 2 feet tall in order to stimulate side shoot development. Any time after harvest, the canes that have fruited should be pruned out, because cane death after fruiting is normal. Then, at the dormant pruning, which should be done in mid- to late winter after severe weather is over but before the buds begin to swell, prune out unneeded canes so that only four or five best-looking canes of each black raspberry plant remain.
Q: When I returned in July from a 25-day vacation, I found that one of the mature oak trees in my lawn just off the water at Smith Mountain Lake had died without having previously shown any sign of trouble. Some of my neighbors are having even worse die-offs of oaks. We thought that it was from some previous or present environmental stress, but now I wonder if it is a disease of infestation. Have you heard of this happening elsewhere, and do you have any clues?
A: I talked to Chris Thomsen with the Virginia Department of Forestry about this, and neither of us have heard about any epidemic nor infestation going on that could have caused the loss of the oaks. In many cases, the death of mature trees that were naturally growing on sites when homes were built near or around them occurs because of the disturbances caused by the construction.
Tree death may be gradual over many years but it can also occur several years after the construction took place. Disturbances could be anything from soil compaction because of construction equipment, to injury from soil level changes, to actual physical injuries, to changes in the water table caused by the new homes and roads.
Send short questions about your lawn, garden, plants or insects to Dear John, c/o The Roanoke Times, P.O. Box 2491, Roanoke, Va. 24010-2491. We need your mail, but this column can't reply to all letters. Those of wide appeal will be answered during the weeks that the subject is timely. Personal replies cannot be given. Please don't send stamps, stamped envelopes, samples or pictures.
LENGTH: Medium: 90 linesby CNB