Horticulture Tips for September

Home Grown  by Keith Reed
Given the incredible weather we’ve had the last week or so, one can’t help but wonder if we are going to have an early fall? Who knows but one thing is certain; the weeds we’ve been talking about the last couple of weeks are ready to jump out of the ground so this is your last reminder. Also included are some other timely tasks for your September landscape:

  • If annual bluegrass, cheat, chickweed, henbit, and other spring weeds typically give you problems, apply a fall preemergent NOW. The window of opportunity is quickly closing as these weeds typically germinate right around this time of year. Some products control these weeds better than others so check the label or contact the Extension office for more information.
  • Remember, you cannot apply preemergent herbicides in areas you are planning to seed! Be especially cautious when applying various “weed and feed” products. Make sure the product will not interfere with your plans for your landscape.
  • Seeding cool season lawns now gives you the greatest opportunity for successful establishment. Tall fescue is generally the turfgrass of choice for shady lawns in our area, but mixes of Tall fescue with a small percentage of Kentucky bluegrass have also shown to work well. Perennial rye should only be considered a temporary turfgrass in our region as it cannot typically make it through the summer.
  • Annual ryegrass use in the home lawn is generally discouraged, even for temporary cover or an overseeding application. As this grass matures, it becomes very tough and difficult to mow, leaving a very unsightly appearance. Left to go to seed, it can also become a troublesome weed.
  • Continue monitoring for fall webworm problems. Early control is much more effective than waiting until webs are fully formed.
  • Some fall garden crops can still be planted such as garlic, mustard, radishes, spinach and others. See OSU Fact Sheet HLA-6009 Fall Gardening for more information.
  • Plant annuals for fall color. Pansies, mums, ornamental cabbage, snapdragons, swiss chard and johnny-jump-ups all provide nice color and can tolerate light frosts and freezes without damage.
  • Keep a close eye on your automatic irrigation system and adjust it as needed for the cooling weather.

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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