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
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, crows 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.