Winter weed prevention – an update

I get at least 200 calls and emails each spring asking how to stop annual bluegrass (Poa annua), rescuegrass, ryegrass and other cool-season grassy weeds. And that’s not to mention the scores of broadleafed weeds like henbit, clover, dandelions and chickweed.

For the grassy weeds I always tell you to apply pre-emergent weedkiller granules Dimension, Halts or Balan the last week of August or the first week of September. Applied before the weed seeds start to germinate (“emerge”), they will prevent the weeds ever from developing. However, if you’re late and the weeds are already established, there is nothing you can do to eliminate them.

So, does that mean that your time is here now? I don’t think so. Not this year. These seeds aren’t going to sprout when it’s as dry as it’s been and when temperatures are this extremely hot.

Annual bluegrass (Poa annua) outbreaks can be reduced with application of one of the pre-emergent granules applied around September 1. There is research underway to determine extent of its resistance to the herbicides. They are still worth using, however, especially when you consider the other weeds they will prevent.

So here is my adjusted recommendation…
Find one of those types of pre-emergent granules, even if you have to ask your local retailer to order it for you.

Continued Below

Store it dry in the garage for a week or two. When the weather finally does break in your part of Texas and day temperatures fall into the 80s, nights into the high 60s, and especially when we get our first rain, apply the granules immediately.

Henbit is a cool-season broadleafed weed that can be prevented with Gallery pre-emergent granules applied around September 1 (perhaps a few days later this year due to temperature and drought). It can also be eliminated with a 2,4-D spray applied in late fall.

Apply Gallery granules if desired to prevent germination of annual winter/early-spring broadleafed weeds such as clover, dandelions, henbit and chickweed. However, in this case, you do get a second chance. If you miss this category of weeds you can always apply a broadleafed weedkiller (containing 2,4-D) to eliminate existing weeds late this fall. You don’t have that opportunity with grassy weeds.

Note 1: Do not apply pre-emergent granules to new lawngrasses until they have been through their first winter. You might impact their root development.

Note 2: Do not apply pre-emergent weedkiller granules if you intend to plant ryegrass for temporary cover of the lawn for the winter.

Continued Below

Note 3: Do not apply pre-emergent weedkiller granules where you have wildflowers.

Note 4: Pre-emergent granules can be used on any type of permanent lawn, also around trees and shrubs, but always read and follow label directions carefully!

Note 5: Your professional lawn care service may have a slightly different schedule than what I prescribe for homeowners. They have access to other products, plus they can’t possibly service all their lawns in a 5- to 10-day period “just because Neil says it’s time to do so.” If they have provided good results, trust their schedule.

Posted by Neil Sperry
Back To Top