Q: This spring I had a terrible crop of parsley piert in my bermuda grass. I want to put a pre-emergent on this September but can’t find a good one for this particular weed. Do you have a suggestion?

A: Parsley piert is particularly difficult to control. This winter annual sprouts in cool weather but becomes noticeable in late spring and summer. Common pre-emergents like dithiopyr and pendamethalin are typically ineffective. Isoxaben is somewhat effective at preventing seed germination but I could find only one product that contains it: Bayer Advanced Season-Long Weed Control. You can also inhibit weed growth by mowing at the proper height and fertilizing your bermuda to keep it growing aggressively. As with lawn burweed, parsley piert control is not a once-and-done task but a years-long process.