The Homeowners Column

The Homeowners Column

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September garden “to do” list

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Sandra Mason
State Master Gardener Coordinator

Out of all the garden topics I write about my "it's time to…" articles get the most feedback. People are either gleeful or regretful that I added something else to their "to do" list. Our culture revolves around "to do" lists and task reminders. However, garden "to do" lists possess a special urgency since nature waits for no one. You can clean the garage (or procrastinate about cleaning the garage) any time of year. But plants will flop, drop, droop, reseed, and revolt no matter how much we scream at them, "Just wait. You're on my "to do" list."

September does allow us a second chance to do all those things we didn't do on our spring "to do" list. Keep in mind gardeners seldom get everything done. Enjoy the process.


  • Divide peonies. Be sure to have 3-5 eyes per division. Replant so eyes are no more than 2 inches deep.

  • Replant areas with frost tolerant plants such as pansies and flowering kale.

  • Plant asters and mums for late season color. Planting on a slight mound may help to provide proper drainage to get mums through the winter.

  • Dig succulents and tropicals for trip indoors before frost. Scout for insects. Thoroughly rinse leaves. Remember the average date of first fall frost for central Illinois is October 16th.

  • Begin 2-3 month dormancy for amaryllis. Do not water. Place in cool dark place. Dormancy begins once leaves yellow.

  • Purchase spring flowering bulbs for October planting.

  • Discontinue rose fertilization.

  • Collect seeds of non-hybrid annual flowers for spring planting.


  • Harvest herbs such as sage and oregano by hanging clean stems upside down in dark space.

  • Pot chives, oregano, basil or rosemary for winter use indoors.


  • Fertilize in early September. This is the most important application of the year.

  • Reseed bare or thin areas with improved cultivars. Consider renting a slit seeder to get seed down into soil of existing lawns

  • Reduce soil compaction and thatch (over one-half inch depth) by using core aerifiers.

  • Establish turf by seed (August-September best time of year). Prepare soil properly and get good seed-to-soil contact. Select turf mixes and blends appropriate to the site and to maintenance practices. Check out University of Illinois Extension's Lawn Talk for more info


  • Continue harvesting vegetables to keep plants productive.

  • Pumpkins and winter squash should have hard rind before picking, otherwise storage may be compromised.

  • Seed bare areas with winter rye or barley for a winter cover crop.

  • Spinach and other leafy crops can be planted for a fall crop.


  • Plant most trees and shrubs. Be sure not to plant too deep. Trunk flare should be visible after planting.

  • Water trees and shrubs. Plants, especially evergreens, should be well hydrated entering winter.

  • Avoid severe pruning now if possible. Wait until February or March for most trees and shrubs. Spring bloomers should be pruned right after bloom.

  • Pick bagworms from evergreens. Pesticide sprays are not effective at this time. Spray with Btk products such as Dipel™ or Thuricide™ next year late June-early July.

  • Remove branches with fall webworm caterpillars or use Btk products within web. However if not managed, late season leaf loss from webworm seldom causes long term impact.


  • Prepare soil now for a spring planting of acid-loving blueberries or rhododendrons. A soil test will indicate how much sulfur to add to lower the pH to 4.8-5.2. Also add plenty of organic matter such as leaf compost.

  • Add plant debris from flower and vegetable areas to compost pile. Debris will decompose faster if it is first shredded or chopped. Also layer with soil or compost.

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