Will Be Most Visible Weed of Autumn

This is the way roadside aster looks now.

Roadside aster seems harmless enough when it starts growing in a lawn. In fact, it’s almost hard to see as it blends in with bermudagrass. (It doesn’t invade St. Augustine nearly as often.) Photo by FB friend Kathy K.

Roadside asters will soon become evident in under-maintained lawns. In fact, it is so dense that you can feel it underfoot as you walk across your lawn. Sometimes it’s about the only thing growing in more distant parts of your yard where it’s hard to get water and fertilizer.

Tufts of roadside asters become all too evident just before they break into bloom. Photo posted by FB friend Brian L. two years ago.

Roadside aster forms mats of dense growth culminating in small, white daisy-like flowers. It germinates in spring and grows over the summer. As fall approaches the plants can get fairly large.

Once roadside aster is in full flower like this it is setting plenty of seeds for next year’s crop. Don’t let it get this far along.

You want to treat it before it starts blooming and going to seed. A broadleafed weedkiller spray (containing 2,4-D) will eliminate it. I prefer to use a tank sprayer so I can spot-treat directly onto the weeds.

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In future years your better approach will be to invest in fertilizer and regular irrigation to help your turfgrass crowd out the annual weed. I refer to it as a “weed of neglect.” It’s one of the first weeds to disappear when we mow and maintain our turfgrass on a regular basis.

This is what roadside aster looks like after it completes its life cycle. Few people want lawns that look like this roadside, yet this black stubble is what’s left behind.

As for whether you might just want to ignore it entirely, I’d suggest that you not do that. It’s extremely uncomfortable, even hazardous underfoot. I know that bees do like it, but there are plenty of other places where they can find it. It makes home lawns downright unsightly once it dies with the first freeze, plus it serves as a source for seeds for the neighborhood.

Posted by Neil Sperry
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