DATE: Sunday, March 9, 1997                 TAG: 9703080073

SECTION: HOME                    PAGE: G2   EDITION: FINAL 

SOURCE: BY LAURIE SMITH, VIRGINIA TECH WEED SCIENTIST 

                                            LENGTH:   46 lines

FORSYTHIA BLOOMS ARE A TIP-OFF ON CRABGRASS PREVENTION

BRIGHT YELLOW BELL flowers of forsythia are a sure sign that spring is close at hand. Those same lovely flowers also serve as a warning that something not so nice is on its way - crabgrass.

Anyone who has dealt with a crabgrass infestation knows it can take a major effort to get it under control.

It really isn't difficult to deal with crabgrass, but it has to be dealt with before it becomes a problem. That means prevention.

In any lawn, it is fairly easy to kill broadleaf weeds such as dandelions with herbicides. It is much harder to kill grassy weeds such as crabgrass.

Herbicides aren't very selective when it comes to killing a grassy weed, such as crabgrass, because it is similar to the grassy plants that make up your lawn.

The solution is to prevent grassy weeds from coming up, which is accomplished by applying a pre-emergence herbicide before grassy weed seed germinates and begins to grow.

Timing is the key to effective grassy weed control. Crabgrass is the most common and earliest germinating of the grassy weeds in a lawn. The best time to apply a pre-emergence herbicide for crabgrass is when forsythia starts blooming. And forsythia is in bloom now.

If you aren't into plant watching or don't grow forsythia, the usual time to apply is the first part of March.

There are many pre-emergence herbicides available for crabgrass control. Some control only crabgrass, while some also control other grassy and broadleaf weeds. Check the herbicide label to see what it controls and whether it is safe on your grass.

When you look at a label, the numbers after the product name are the percentage of herbicide in the product. Usually the higher number means you get better control, but the product also costs more. The ``G'' means the product is granular. When three numbers are listed, such as ``28-3-4,'' that is the analysis of the fertilizer, if the product is a herbicide-fertilizer mix.

Some in the horticultural industry say the herbicide Pendimethalin is considered the most effective. MEMO: Laurie Smith is a weed expert at Hampton Roads Research Center.

Garden columnist Robert Stiffler also contributed to this report. KEYWORDS: WEEDER'S DIGEST

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