WEED CONTROL

            The question is being asked, “Why so many weeds this year and what should we do with them?” The reason we have so many weeds is that we had two conditions over the summer and winter that made it ideal for weeds. The drought reduced plant cover this summer, leaving plenty of bare ground and gaps in our lawns where weed seeds could reach the soil. The cool, wet weather this winter made ideal conditions for germination and growth of weeds. The result is tremendous growth of rescue grass, henbit, bedstraw, thistles, medic, and other weeds.

            Wildflowers are weeds, too. How are they faring in this weed fiesta? Early in the season, it looked like it might be a spectacular season for wildflowers; unfortunately, the rains were too much of a good thing. The larger, more aggressive weeds will overrun bluebonnets and other wildflowers on the moister sites with relatively good soil. On sites with shallow soil, the wildflowers are already showing and will make a fair show. In addition to bluebonnets, the primrose, Mexican hat, wine cups, crow’s foot, and verbena are already blooming. The peak bluebonnet period will probably be three weeks from now, in early April.

            The best thing to do to control the cool weather weeds (the undesirable ones!) at this point is to keep them mowed in order to prevent seed production. It is pretty late to apply a contact herbicide like Wipe-Out, Weed-Be-Gone or even Round-Up. The contact herbicides are unpredictable in cool, wet weather and the “kill” probably will not come fast enough to prevent seed production. Warm weather will kill most of the weeds next month anyway.

            Speaking of warm weather, I have seen Bermuda grass growing in raised bed gardens. It will not be long before all the wonderful warm weather weeds move in to replace the cool weather weeds. If you have trouble with crabgrass and especially sandburs I would still apply a pre-emergent herbicide even if a few escape its effect and germinate anyway. There are a number of effective pre-emergents. Check the list of weeds controlled on the labels of Amaze, Portrait, Balan, Betasan and others to see which prevents the weeds you have in the summertime.

            The best way to battle weeds is to have a strong lawn or, better yet, groundcovers or mulched perennials. Weeds do not compete well with a thick St. Augustine, zoysia or Bermuda lawn. There is no such thing as a thick buffalograss lawn but, if the drought tolerant grass is used on heavy soil in full sun with a western or southern facing slope, watered sparingly and mowed high, it will out-compete weeds during dry years. During wet years, keep the herbicides handy if you have a buffalo grass lawn.

            To encourage your lawn to thicken up, it is not too late to aerate and top-dress with a half-inch of compost. Rent the type of aerator that cuts plugs rather than the spike type. Wait until after April 15 to fertilize the lawn. Use a slow release fertilizer such as 19-5-9, 20-5-10, or one of the organic fertilizers. Do not waste your money on weed and feeds. If you apply the product now it is too early for the fertilizer to be useful to the grass, so you are fertilizing the same weeds that you are trying to kill. If you wait until mid April or May when the grass can use the nitrogen, it is too late for the herbicide to kill the weeds. Another problem results when we forget that the weed and feed bag includes a herbicide after it sits in the garage or shed for awhile. Listen to my radio show on KLUP 930 AM on Saturday or Sunday and at least one person a weekend has forgotten and killed flowers, shrubs, or vegetables with their weed and feed.

There are less errors and environmental threats if we keep our fertilizer separated from our herbicides.