Important Landscape Dates for Weed Control

Home Grown  by Keith Reed
If you are a regular reader of this column, you know that one of the services the Payne County Extension Service offers is one-on-one advice for a variety of horticulture and landscape questions. Often these questions involve helping our clients solve a variety of problems. This week’s focus is on weeds. We will follow up next week with other gardening tasks.

Prevention is key. And a key component to prevention is proper timing. Take a look at this list and mark your calendars now with a reminder because these common issues sneak up on us every year!

Successful weed control can begin very soon. Warm (over 50 degrees) and sunny winter days of January, February and early March is the best time to spray for winter annual weeds. Don’t let the name winter fool you, these are the weeds you battle every spring. Weeds like annual bluegrass, cheat, henbit, chickweed, etc. started coming up early last fall and are already positioning themselves for rapid spring growth when the days warm.

As we get later into the spring, the weeds become harder to control. Also, the herbicides that kill these weeds can also easily damage sensitive spring crops by drifting off-site.

The next key date for weeds involves crabgrass control. When forsythia and redbuds are in full bloom, it’s time to apply. For us, this usually means the last part of March but I suggest marking the calendar reminder around March the 10th as earlier is better than later. Depending on which product you use, a follow-up application may be needed, especially if you are attempting to control difficult weeds like goosegrass or sandburs. Check the product label and note accordingly.

Finally, target the last week of August if you wish to prevent the winter weeds mentioned about from germinating. A fall pre-emergent, while not critical, can be especially helpful for controlling annual bluegrass in tall fescue as well as helping to control weeds in ornamental beds. This is probably the treatment most often missed or overlooked altogether since it’s often still 100 degrees or better and the last thing we have on our mind is “winter” weed problems.

These weeds often begin germinating the first wet cool-off we get. Some years that is in the last part of August, and some years it’s not until almost October. Once again, early is always preferable to waiting until it’s too late.

For more information on this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at
keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

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