Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, July 4, 1993 TAG: 9307050115
SECTION: HOMES PAGE: E-1 EDITION: METRO
SOURCE: John Arbogast
DATELINE: LENGTH: Long
A: Basically, fertilizers can be effective just as soon as the nutrients applied go into solution in the soil and plant roots can absorb from that soil water. Thus, water soluble fertilizers may be more efficient for flowers or vegetables.
I don't believe your efforts using the water soluble fertilizer were to no avail. The leaching potential of nutrients applied to soil must be considered. Nitrogen, which is listed first in the three numbers identifying a complete fertilizer, does run through (leach out of) the soil fairly quickly. In our area, though, we have a lot of clay in our native soils, so leaching is not as rapid as in a sandy soil. On the other hand, phosphorus and potash, the middle and third numbers given to identify a complete fertilizer, usually are held fairly tightly by soil particles, thus reducing their leach potential.
Fungicides and insecticides are supposed to adhere to plant parts and thus should do their intended work if the spray has time to dry thoroughly before rains or irrigation. The dried spray residue is hard to wash off completely. So, if your black spot fungicide had sufficient time to dry completely before the rains, the material should have been fairly effective. Of course, heavy rains will definitely remove an unknown portion of any spray residue, thus making disease control difficult during very wet seasons.
Q: Although my Kousa Dogwood has bloomed fairly well in the past, this year not a single blossom appeared. I have also noticed other Kousas with sparse blooms this spring. What happened? T.H., Blacksburg
A: Some weather-related factor that occurred last summer or fall might be the cause of your lack of Kousa Dogwood flowers this spring. Particularly, I would suspect the unusually heavy amount of rain with some periods of drought that our area experienced in '92. I do not know of any specific disease or pest problems experienced by the Kousas in Roanoke recently.
Q: I have an oak tree in my yard that needs to have the lower limbs removed. Would it be all right to cut them at this time? Also, when is a good time to transplant tree peonies? M.D., Floyd
A: It is OK to remove some limbs from a healthy shade tree any time through midsummer. If you have several living lower limbs that must come off, phase the work over two or three years so that the tree is not weakened by a major reduction in the number of leaves at one time.
Wait until the end of the growing season when the peonies' leaves are declining to transplant tree or garden peonies.
Q: Hemlock trees in our neighborhood are developing a white mold or fungus on their branches and foliage; we are told that this constitutes a blight that eventually will kill the trees. We have also been told that while some trees have been sprayed with what owners were told was an appropriate chemical, the white mold or fungus persists. Your advice will be appreciated. B.L., Martinsville
A: I don't know of a mold or fungus attacking hemlocks, but I am very aware of an insect pest called the hemlock woolly aphid (actually an adelgid) that is running rampant on hemlocks. The presence of this pest is shown by masses of small grayish white puffs or balls positioned along the branches and at the base of hemlock needles. In the Dear John column of Feb. 28, I addressed the pest and discussed the latest control, which would be a thorough application of a horticultural oil spray.
Get a personal diagnosis of your hemlock problem. Call and then take a fresh sample to your local Henry County Extension Office in Room 102 in the County Administration Building, King's Mountain Road, Collinsville. Telephone (703) 638-5311.
Q: I need information on black raspberries. For several years I have watched mine bloom and then berries form only to dry up and drop. What is wrong? Mrs. O.W., Bedford
A: There may be a physical cause for this, such as a soil that won't hold moisture during berry-ripening time, since berries form but then dry up and drop off. Are the leaves and canes also drying up? If so, that could point to a pest problem such as spider mites. There are viruses that can affect the brambles causing fruit problems. Take a fresh sample of leaves, a cane and affected fruits when this occurs next time but before the berries drop to your Bedford County Extension Office at 122 East Main St. in Bedford. Telephone (703) 586-7675.
Send short questions about your lawn, garden, plants or insects to Dear John, c/o the Roanoke Times & World-News, P. O. Box 2491, Roanoke. 24010-2491. Please note: We need your mail, but this column can't reply to all letters. Those of wide appeal will be answered each week. Some Dear John mail will be saved for printing at times of year when reader mail is sparse.
John Arbogast is the agricultural extension agent for Roanoke.
by CNB