Show and tell.

Tulsa Master Gardeners offer this gardening classes on October 29th at 5:30 pm and will last approximately 30 minutes with another half hour for discussion.

 

This class is free and there is no need to register, just show up. They are held in the auditorium at the OSU Extension Office, which is on 15th street at gate #6 into the Tulsa Fairgrounds.

As we exit summer and enter a more pleasant time of year, many gardeners are thinking about things like fall vegetable gardens, planting trees, and seasonal plants. But, you should also be thinking about weed control. There are a number of winter and early spring weeds which require some control measures right now. These winter annual weeds germinate in late September and October and die the following summer. Examples of commonly found winter annual grassy weeds include annual bluegrass, cheat, downy brome, little barley, and rescuegrass.

Preemergent herbicides should be on the ground by September 15, ideally. This offers good preventative control of both grassy and broadleaved winter weeds if used correctly. However, if these weeds are already established, then postemergent herbicides are useful.

The common winter annual broadleaf weeds, including chickweed, dwarf fleabane, and henbit, can be safely controlled in all established Oklahoma turf grasses by applications of a usual mixture of 2,4-D, Banvel, or MCPP combinations (Ortho Weed-B-Gon, Trimec, Bayer Advanced Weed control). Some combination postemergent brands may have other chemicals as well. These products are variations of plant growth hormones and are best used when weeds are growing, especially after it cools in fall. Fall is the best time of the year to use postemergent herbicides for broadleaved weeds.

In newly seeded fescue/bluegrass lawns these 2,4-D type herbicides may be used to control weeds that germinated along with fescue after the 3rd mowing of the newly planted fescue.

There is no good chemical available to homeowners for control of grassy weeds in turfgrass since MSMA was removed from the market. However, they can be controlled in Bermuda grass after it goes dormant. Green grassy weeds and all green broadleaved weed can have excellent control with glyphosate (found in Roundup and others) in December and January. Glyphosate cannot be used on zoysia, fescue, ryegrass or bluegrass at any time.

These chemicals are effective when used according to the label, but come with a downside to them. 2,4-D is highly volatile and it's vapor may carry for long distances, causing undesirable damage to other plants. It is essential to heed the wind restrictions when spraying 2,4-D. Dicamba found in many of these mixtures is very mobile in the soil and can cause damage to trees and shrubs having roots in the lawn where the herbicide is used. As long as you follow the labeled directions strictly, these herbicides are useful and safe. Always avoid the "more is better" approach!

Post-emergent herbicides are generally foliar applied and absorbed, so they must remain on the leaf surface for 24 to 48 hours following application for adequate absorption. Do not mow for two days before or after herbicide application to ensure satisfactory leaf area coverage.

For much more information on this subject, see the OSU Extension Fact Sheet HLA-6421, Controlling Weeds in Home Lawns. For best concise current chemical suggestions for control of all weed types obtain a copy of both the Bermudagrass Maintenance and Fescue Maintenance Calendars.