GARDEN COLUMN FOR THE SALISBURY POST

Darrell Blackwelder

March 28, 2003

    Bad weather and other projects around the house have delayed working in yard the this spring. Warm weather last week has made my grass and unfortunately, a host of weeds, grow at an incredible rate. I applied a postemergence herbicide in an effort to head the weeds last week. and I recognized results two days after application.
    Postemergence herbicides are designed to control weeds after they have emerged. Broad leaf weeds such as chickweed, henbit, clover, wild garlic, dandelion and others examples of broadleaf weeds controlled by postemergence herbicides. There are a few herbicides on the market that claim to control crabgrass and other grassy weeds after they have emerged, however, success with these herbicides are somewhat limited.
Broadleaf weeds are fierce competitors for space, sunlight, water and nutrients. Competition by employing by employing sound cultural practices. Vigorous and healthy lawns discourages both winter and summer weed growth. Ironically, many weeds actually thrive on poor soils and adverse growing conditions.
    One method of controlling weeds is to mow cool season grasses to a height of three and a half to four inches. Shade from the turf discourages weed seed germination, especially crabgrass and dandelion.
Broadleaf winter weeds have emerged in most lawns after the warm weather. Winter annuals germinate in late September when soil temperatures drop below 58 degrees and lay somewhat dormant during the winter until early spring. Chickweed seems to be the most serious weed so far, followed by henbit, wild garlic (some refer to as wild onions) and dandelion. These weeds may be controlled with applications of a post
emergence herbicide. Most broad leaf weed herbicides or "weed killers" contain a mixture of various herbicides, such as 2,4 D and dicamba. Post emergence herbicides such as Trimec, Weed B-Gon, Spectrum 33+ and various other formulations are applied to existing weeds in turf. These broadleafed herbicides are formulated not to injure cool season turf itself.
    Broadleaf herbicides are usually sold as liquid formulations
and are applied with compression sprayers or hose on applicators. Both systems work well for broadlead weed control. I prefer the disposable hose on ready mixed applicators because of the simplicity and I don't have be concerned about storage. Simply attach to your garden hose, spray and toss the empty container in the garbage.
    Broadleaf winter annual weeds in bloom are difficult to kill. These plants generally do not absorb herbicides at this stage of growth. Broadleaf weeds should sprayed at an early growth stage; therefore the younger the weed, the easier to control with herbicides. The problem facing now homeowners is many of the winter weeds have achieved excessive growth and are difficult to control.
    Broadleaf postemergence herbicides also are sold as granular formulations or impregnated on fertilizers. Fertilizers with herbicides are more convenient and easier to apply than liquid herbicides but can be pricey. Also, fertilization is only recommended for the early spring and fall. Controlling weeds with postemergence herbicides in the summer is not recommended on cool season lawns.