WINTER WEEDS: THE TRIFLING TRIUMVIRATE OF WEST TEXAS
BY: C.L. Eaton, County Extension Agent
Although the past month has dried out some, December and
early January were wetter than average and now we are seeing the downsides to a
wet winter (unless you’re in the cattle business)…WINTER WEEDS! Although there
are several species and varieties of winter weeds that effect our landscapes
this time of year, I’m going to focus on three individuals that I believe are
the most prevelant this month (the “Trifling Triumvirate”) I hinted to in the
title: Tansy Mustard Weed/London Rocket, Henbit, and Rescuegrass.
But before we get into the individual weeds, here are a few
reminders before you act to eradicate these pests:
·
Prevention
is the best solution. Putting down a pre-emergent before the seeds germinate in
early winter can at least deter a full on infestation of winter weeds. Also,
keeping your lawn healthy and free of bare spots before dormancy also keeps the
weeds from gaining a foothold.
·
If
applying a post-emergent herbicide, remember to be careful of unintentional
coverage on your desireable plants, for example be careful around trees/shrubs
when using a broadleaf weed killer or ornamental grass when applying a grassy
weed killer.
·
Stay
away from “Weed and Feed” products….PERIOD
Now
onto the “Trifling Triumvirate”….
TANSY MUSTARD WEED/LONDON ROCKET
Yes, yes, I know that technically these are two separate species (Descurainia pinnata & Sisymbrium irio), but their near identical appearance and history of sprouting side-by-side behooved me to pair them together. Both have dainty, yellow flower and start out as small rosettes then grow to abt. 2’ tall at maturity. Both have a taproot that identifies it as an annual plant. Post emergent control of these two can be easily attained using a broadleaf weed killer that contains either or both of the chemicals 2-4,D or Dicamba. Mowing with a bag and disposing of the clippings can also deter spreading the seed for next winter. The taproot of these weeds also make them fairly easy to pull (if you have some kids/grandkids who desperately need to build character). Once temperatures begin to climb into the 80’s and 90’s, these weeds will wither and die, leaving brittle skeletons.
HENBIT
This purple-flowered pest (Lamium amplexicaule) grows from 4” to 12” in height and almost seems to
creep along the ground, rather than stand upright due it its weak stem
structure. The stems are green in the juvenile phase, but turn red upon maturity. Henbit leaves are
round with scalloped edges and are spaced out evenly along the stem. Post
emergent control can be achieved using
the same broadleaf weed killer (products
with 2-4,D and/or Dicamba) as Tansy Mustard.
Because of its low stature and weak stems, mowing or pulling may not be
very successful with henbit.
RESCUEGRASS
This cool-season pest differs quite a bit from the previous two plants. For one, Tansy Mustard and Henbit are both broadleaf forbs, while Rescuegrass is a grassyweed. Also, while both of our broadleaf plants are native to Texas, Rescuegrass (Bromus catharticus) is an invasive plant. It was brought in from the Mediterranean and has set up shop throughout most of the southern U.S. This grass is generally spotted sprouting in scattered bunches in mid to late winter and by Spring has sprouted a rather easily recognizable “oat-like” seedhead that turns to a purple color at maturity. Post-emergent control of Rescuegrass can be attained early on with Glyphosate or another grassy weed killer, but once the lawn has began to green up from dormancy, use of a post-emergent herbicide can cause damage to your lawn. Mowing with a bag can also help prevent the further spread of this grassy weed.
Taking these steps before the spring green-up will give your lawn an extra leg up to reaching its full potential this spring, sans the weeds!
- video courtesy of Skip Richter, CEA-Horticulture (Harris County)
SOURCES
Aggie Horticulture
Skip Richter
(CEA-HORT) Youtube Channel
Jeff
Floyd, CEA-Hort (Ector/Midland Counties
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