Questions of the Week: October 15, 2020

“How do I get rid of these weeds?”
(The actual weeds will vary, as will the controls, but the questions keep coming up.)

I’ve had these questions each a dozen times in the past week, and to be honest, I feel helpless with both. I’ll explain why.

Grassburs…
These are annual grassy weeds that germinate in early spring, grow vigorously in spring and summer, and then start producing their annoying seeds from mid-summer on.

Grassburs, also commonly known as sandburs, are usually found in sandy soils. We no longer have post-emergent herbicides that will control them once they are up and growing actively. Your only options will be to apply pre-emergent weed killers in the early spring, with a repeat application 90 days later in early summer.

Products and timing are critical: You can choose from Dimension, Weed-EX with Halts or Balan, all in granular form. Apply them two weeks prior to the average date of your last killing frost for your part of Texas, then put a second (“booster shot”) application down 90 days later.

Once you can see the plants growing (and certainly once they start producing their stickers) there is nothing more you can do to stop them for that growing season.

Roadside asters…
This little flower grows atop fine-leafed clumps of green that develop all summer, then suddenly pop into bloom in the fall. You’ll see it primarily in the rougher parts of your lawn where you have the hardest time getting water and fertilizer and where you may be less likely to mow it.

Your best way of eliminating it will be to ramp up your lawn care so the turfgrass will crowd it out. (It’s easily discouraged.) However, it’s also easily controlled with an application of a 2,4-D broadleafed weedkiller anytime you see the clumps of its tiny leaves and woody, low-growing stems. Just try to stop it before it comes into full bloom and starts setting seeds for next year.

Here is a link to the longer piece I wrote on it last week.