September 2023 Gardening Tips
Friday, September 1, 2023
Landscape
- Watch for fall specials at garden centers and nurseries since fall is a great time for planting many ornamentals.
- Choose spring flowering bulbs as soon as available.
- Plant cool-season annuals like pansies, ornamental cabbage or kale, snapdragons and dusty miller when temperatures begin to cool.
- Watch for and control any late infestations of tree webworms.
- Twig girdler insects should be controlled if large numbers of small branches of elms, pecans, or persimmons are uniformly girdled from the tree and fall to the ground.
- Begin to reduce the amount of light on outside tropical houseplants by placing them under shade trees before bringing them indoors for the winter.
Vegetables
You have all of September to plant cool-season vegetables like spinach, leaf lettuce, mustard and radishes, and until the middle of September to plant rutabagas, Swiss chard, garlic and turnips.
Lawn
- Last nitrogen fertilizer application of the year on warm-season grasses should be applied no later than September 15. (HLA-6420 Lawn Management in Oklahoma)
- Winter broadleaf weeds like dandelion will begin to emerge in late September, which is also the best time to control them with a 2, 4-D type herbicide.
- If pre-emergent control of winter-annual weeds (henbit, chickweed, annual bluegrass, etc.) is desired in lawns, the application should be completed by the second week of September. (HLA-6421 Controlling Weeds in Home Lawns) Note: Do not treat areas that will be seeded in the fall.
- Continue bermudagrass spray program with glyphosate products for areas being converted over to tall fescue this fall. (HLA-6421 Controlling Weeds in Home Lawns)
- Plan to seed bluegrass, fescue or ryegrass as needed in shady areas in mid- to late-September. Fall is the best time to establish cool-season lawns (HLA-6419 Establishing a Lawn in Oklahoma).
- White grub damage can become visible this month. Apply appropriate soil insecticide if white grubs are a problem (EPP-7306 Ornamental and Lawn Pest Control (for Homeowners)). Water product into soil.