Pre-emergent – Failure
Q: I have a bermudagrass lawn, about two and one-half years old. I put down pre-emergent in the fall and even used the weed killer hose spray for weeds. I had the lawn aerated also. Presently, I have numerous henbit weeds all over. My next door neighbor does not have a one. I have recently spot sprayed with a weed killer. I do not understand why I have all these weeds. Can you offer any suggestions?
A: There could be several reason the pre-emergent failed.
1. Did you use a product designed to control broadleaf weeds or one designed for grassy weeds?
2. Did you put it down by mid-September, when chickweed and henbit was beginning to sprout, or did you delay until afterwards?
3. Did you water it in (as the label directs) after spreading the pre-emergent?
Once broadleaf weeds are up and growing, a spot spray of post-emergent weed killer is your best option. Several are effective, including Ortho Weed-B-Gon, Green Light Wipe-Out and Enforcer Weed-Stop.
If you are unsure when to apply a pre-emergent for next summer weeds, mark your calendar for March 15. Since your bermuda lawn is well-established (not newly sodded), a spring-applied pre-emergent, which is properly irrigated after spreading, should control annual summer weeds. Next September 15, apply a broadleaf weed pre-emergent and irrigate afterwards with one-half inch of water.