Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, October 31, 1993 TAG: 9311010356
SECTION: HOMES PAGE: E-1 EDITION: METRO
SOURCE: John Arbogast
DATELINE: LENGTH: Long
This is the late fall turf grass fertilizer application that specialists at Virginia Tech say is so essential for a high quality bluegrass/fescue lawn. This suggested application must follow fertilization in September and October so that there will be plenty of green grass tissue for the final treatment to work with.
Don't be misled by the words "late fall application." Actually, this final quick-release nitrogen application should be applied before the first of December.
Adequate fall fertilization of bluegrasses and fescues should take the place of spring fertilization. I know this can be confusing because lawn service people many times apply fertilizers in the spring and summer. Also, spring seems to be when garden centers put the various "turf foods" on sale. At this time of year, do-it-yourselfers may find that some garden departments have moved what's left of their lawn fertilizers to the "back room", therefore a little shopping around might be necessary.
Virginia Tech suggests applying nitrogen to bluegrass or fescue in the fall because this will encourage excellent root growth plus the storage of food reserves, both of which will be needed to help bluegrasses and fescue make it through our typical stressful summer conditions.
On the other hand, think what happens when the well-meaning lawn owner gives a regular dose of nitrogen to a bluegrass/fescue lawn in the spring. We know there will be a lot of mowing to do and a lot of clippings to dispose of as a result. From the grass plant's standpoint, though, rapid top growth of the grasses in the spring coincides with stopped root growth. It appears that nitrogen fertilization during the period of rapid spring blade growth has the negative effect of decreasing those food reserves in the bluegrass or fescue.
And don't forget the importance of soil testing to proper lawn fertilization. Nutrients applied or already in the ground can't be utilized by the grass plants if the soil pH is too high or low.
Q: Twenty-five years ago, when webworms were destroying mimosa trees in Virginia, I heard that in another two decades there would be no mimosas left on the East Coast. Now I see them everywhere, even on the Outer Banks of North Carolina. What happened? E.L.B., Charlottesville
A: I talked with Dan Henry, urban forester for the city of Roanoke and a forestry graduate of Virginia Tech, to get advice on answering your letter. First, let me say that I am not familiar with the prediction made 25 years ago.
Let's look at some facts that can explain the mimosa situation:
Not every mimosa tree gets the mimosa webworm; a more serious threat to mimosas is a wilt disease that these trees are susceptible JOHN ARBOGAST to and for which there is no control.
The extent of damage to mimosas from the mimosa webworm is probably not all that catastrophic; actually, in this country, the honey locust is a more damaging than mimosa for the mimosa webworm.
Usually a mimosa webworm infestation will not defoliate a whole mimosa tree. Remember that it takes repeated early season complete defoliation to weaken a tree enough to cause death; an example of that in areas north of Roanoke has been repeated Gypsy Moth damage.
Although foliage is lost as a result of mimosa webworm feeding, it is difficult for anyone to assess the actual damage to the leaves, since this injury is often hidden by the webbing.
Q: In light of the threat to our trees - gypsy moth, pine beetles, hemlock aphids, dogwood anthracnose, etc. - what trees do you suggest that we plant? I would like to think that there will be some trees on my property 10 years from now. C.B., Catawba
A: Many landscape trees are susceptible to one or more pests (includes insects and diseases), so we can't give up in despair. Some of the threats might not occur or might cause only minor damage.
We do need to provide optimum care of our trees and select trees that are best suited to the conditions of a given site. Take, for example, pine beetles. This infestation has seemed to follow drought stresses, so irrigating susceptible pines before they are stressed would be a way to avoid that problem.
Fatal dogwood anthracnose is an example of a problem that might not occur. The fungus that causes the disease likes cool, wet conditions, not weather like the Roanoke area has experienced in recent years. Also, we can plant flowering dogwoods from a nursery, not from the wild, and should locate them where they will not be crowded by other plants and where they will have good air circulation to avoid that fungus.
My advice for selecting trees to plant is to ask the professionals.
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, Va. 24010-2491. We need your mail, but this column can't reply to all letters. Those of wide appeal will be answered each week. Personal replies cannot be given. Please don't send stamps, stamped envelopes, samples or pictures.
John Arbogast is the agricultural extension agent for Roanoke.
by CNB