
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: SUNDAY, March 24, 1991                   TAG: 9103250352
SECTION: HOMES                    PAGE: E-5   EDITION: METRO 
SOURCE: John Arbogast
DATELINE:                                 LENGTH: Medium

STOPPING CRAB GRASS SHOULD BEGIN IN APRIL/

One of the most troublesome grassy weeds in our area is crab grass, that flat-growing clump grass with pale bluish-green long blades that comes from seed each year.

Before the soils warm up much and crab grass seeds start to germinate in early April is the time to apply a crab grass preventer.

There are various crab grass pre-emergent controls or preventers on the market. The key point is to read the label or package instructions both before selecting a product and before applying.

The premise of controlling annual weeds with pre-emergence controls is to create a barrier in the top half-inch of soil that will kill seeds as they germinate. Anything that disrupts or dilutes that barrier may make the pre-emergence control ineffective.

Some common crab grass pre-emergent controls (or preventers) with a common trade name given in parenthesis are: Benefin (Balan); Bensulide (Betasan or Betamec); DCPA (Dacthal); Oxadiazon (Ronstar); Pendimethalin (Halts); and Siduron (Tupersan), which is the one crab grass pre-emergent herbicide that can be used to kill annual weedy grasses as they germinate but will not harm the germination of bluegrass, tall fescues, or perennial ryegrass. It should be used where spring turf overseeding projects are planned.

To reduce the presence of crab grass without chemicals, turf people have known for years that short mowing should not be done, since lower cutting heights encourage more weeds, especially crab grass. The cutting height of a mower used on a bluegrass lawn should be set on about 2 1/2 inches and on 3 inches for tall fescue.

By the way, the other major grassy weed, one that folks sometimes confuse with crab grass, is wire grass, a vigorous, perennial creeper that is dormant now. It has long, wiry runners that allows it to take over lawns, flower beds and landscaped areas. Wire grass control, except for pulling, is not feasible at this time of year.

Q: I need to know what type of treatment, such as fertilizing, a Norway spruce that was planted last spring should receive. When planted, the understanding that I got was that it wouldn't need anything but water at the time. It did show a little growth during the summer months. It was a young tree when planted. I'm not rushing it to be a giant but thought maybe it would need some type of treatment this year. Mrs. R.C., Clifton Forge

A: If the growth was satisfactory last year, both in terms of color and amount, I wouldn't fertilizing this spring. Weekly waterings may continue to be a needed when the weather is very dry, if the area that the spruce was planted in tends to be a dry location. If the needle color of your spruce was lighter than normal, the tree can be fertilized in April with 10-10-10 at these amounts based on the height of the plant: 2 to 3 feet tall, 3/8 to 1/2 cup; 4 to 8 feet tall, 3/4 to 1 cup.

Apply the fertilizer uniformly over the root area, starting about 6 inches from the trunk and extending out about a foot beyond the ends of the branches. Scratch the fertilizer into the mulch or grass with a rake and water in thoroughly.

[AUTHOR] John Arbogast is the agriculture extension agent for Roanoke

by CNB