September: Gardening To-Do List

The month of September marks the beginning of fall!  And you know what fall brings…… Mums, Pumpkins and Pansies, OH MY!  


  • Prepare your flowerbeds and containers for mums, pansies, and ornamental cabbage and kale!
  • This fall, think spring!  If you have always wanted a flowerbed full of beautiful tulips, the time to plan for it is now.
    • Think about which spring-flowering bulbs you most enjoy (crocus, allium, daffodils, tulips, or one of the many other spring show-stoppers) and start preparing a place for them now.
    • When you begin planting pansies, leave some space to plant bulbs when the time is right.  Next spring your garden will be such a treat as it rewards you with hyacinth, daffodils, and tulips popping up among pansies!
    • Spring bulbs (tulips, daffodils, hyacinth, etc.) arrive in mid-September.
    • Check out our Bulb Planting Guide for more information
  • Seed bluegrass, fescue or ryegrass as needed in shady areas in late September through mid-October.


  • Water newly planted trees and shrubs properly for the first couple of seasons to ensure they get well-established and thrive.
    • Read our blog post to learn more: Watering Newly Planted Trees and Shrubs
    • Also see our Watering Guide for general watering tips, signs of over- and under-watering, and winter watering guidelines



(typically bermudagrass lawns in Oklahoma)

  • Make the last nitrogen fertilizer application of the year on warm-season lawns no later than September 15.  Fertilizer applications made too late in the summer can stimulate lush fall growth which hinders bermuda grass winterization.
    • We recommend using Marcum’s Nursery’s ‘The Original 18-6-12 Slow Release Fertilizer’ for the final fertilizer application of the season.  Our 40 lb bag of ‘The Original’ will cover the following square footages based on the amount of nitrogen you wish to apply.
      • 2,400 ft2 – 3 lb nitrogen/ ft2
      • 4,800 ft2 – 2 lb nitrogen/ ft
      • 7,200 ft2 – 1 lb nitrogen/ ft2
  • Make an application of pre-emergent for winter weed control by the middle of September.  Make sure to water treated areas with ½” of water immediately after application.
    • ferti-lome For All Seasons II Lawn Food Plus Crabgrass and Weed Preventer (Prodiamine) ferti-lome For All Seasons II Lawn Food Plus Crabgrass and Weed Preventer (Prodiamine)
      •  Fertilize and prevent weeds in one step with For All Seasons II
      • It can be used on warm and cool season lawns (DO NOT use this product in areas where you plan to seed cool season lawns)
      • Controls Henbit, Oxalis, Poa Annua, Chickweed, Crabgrass, Foxtail, Purslane, Shepherd’s Purse, Prostrate Spurge, Knotweed and others listed on label
      • Covers 5,000 ft2
    • Sure Green Sandbur & Crabgrass Preventer Plus Lawn Fertilizer
    • Hi-Yield Turf and Ornamental Weed & Grass Stopper
      • Provides superior control of Crabgrass and many other annual grass and broadleaf weeds
      • Can be applied up to four weeks later than other preemergence Crabgrass preventers  
      • Use in ornamental landscape areas, established lawn s and ornamental turf
  • DO NOT apply pre-emergent herbicides in areas you plan to overseed with fescue, bluegrass, or ryegrass this fall.
  • Seed fescue, bluegrass, or ryegrass in shady areas when daily mean temperatures of the upper soil surface range from 68-86°F.  In Oklahoma this usually happens in late September through October.
    • After seeding, cover the seed with soil to a depth of approximately 1/8”.
    • To ensure proper seed-soil moisture contact, firm the soil around the seed by rolling with a weighted lawn roller or by some other means of packing the seedbed.  The chances of establishment from seeding cool-season grasses is only high if newly emerging root is able to penetrate the soil surface easily and if the surface is kept moist.
    • Keep the upper 1” surface of the soil moist with daily waterings for at least 10-14 days.  Waterings should be enough to keep the soil moist but not so heavy they wash seed away.  After the seed germinates and becomes established, begin deeper, less frequent waterings.   
  • Apply ferti-lome F-Stop for brown patch disease on fescue


  • Plant container grown trees and select deciduous ball and burlap (B&B) trees for fall/winter installation.
    • Visit the ‘Trees’ page on our website to find trees that meet your needs and reflect your style.  Then visit one of our locations to speak with a tree expert who can confirm your selections, provide advice on proper placement, and equip you with the knowledge and tools you need for success.


  • Apply Hi-Yield Grub Free Zone III to keep mole crickets and white grubs away all season long.
    • Remember those beetles that emerged in early summer and fed on the plants in your garden?  Well, they also laid their eggs in the soil in your lawn.  Later in the summer, the grubs will hatch and begin to feed immediately while also moving deeper into the soil so they can survive the winter.  Grubs that survive the winter will become large, mature grubs that move back to the upper soil levels later becoming adult beetles that emerge in early summer to start the process all over again.  An application of Hi-Yield Grub Free Zone III insecticide to your lawn can lessen the population of beetles next summer by killing the grubs as they eat their way down to lower soil levels.  Another application in spring or early summer next year will control any remaining grubs as they move back toward the soil surface.


Note: Thanks to Oklahoma Coop Extension Service for providing some of the suggested maintenance guidelines.

For questions regarding September maintenance guidelines, please call Goldsby 405 288-2368, Oklahoma City 405 691-9100,  Norman 405 447-3100 or Ardmore 580 223-1846.