The Homeowners Column

The Homeowners Column

September Garden "To Do" List

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator

My reaffirming belief is that plants are amazingly tenacious. Our lawns look spring green when I was afraid they would stay winter brown. Many perennials have bounced back. My Japanese painted ferns show the fronds of new growth when just a month ago they showed only brown carcasses. Despite the new growth of many plants we should not assume all is well, especially with trees. This summer's drought will be the source of many tree's weak growth for the next several years. I suggest treating trees as recovering patients - hold off on severe pruning and be sure to mulch and water regularly if needed.

September is the month of second chances. A chance to plan and plant, dig and divide; to do all those things we didn't do in our gardens in the spring.


  • Transplant and divide most perennials.
  • This is the best time to divide peonies. Be sure to have 3-5 eyes, which resemble pink noses, per division. Replant so eyes are no more than 2 inches deep.
  • Replant containers with frost tolerant plants such as mums, pansies and flowering kale. Place old plants in compost pile. No need to replace soil unless diseases were a problem.
  • Plant mums into well-drained garden areas. Plant on a slight mound to provide proper drainage to get mums through the winter.
  • Prepare houseplants for return trip indoors. Scout for insects. Thoroughly rinse leaves and container. Move to a sheltered area.
  • Begin 2-3 month dormancy for amaryllis bulbs. Do not water. Place in cool dark place. Dormancy begins once leaves yellow.
  • Purchase spring flowering bulbs for October planting.
  • Discontinue rose fertilization. Remove diseased leaves.


  • 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.
  • Order garlic bulbs for planting in mid-October. Try softneck and hardneck varieties.


  • Mow to 2 inches and water as necessary.
  • 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 thatch if more than one half inch by using core aerifiers or vertical mowers.
  • Core aerifiers may be used to reduce soil compaction.
  • Establish turf by seed (best time). 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


  • Continue harvesting vegetables to keep plants productive.
  • Add compost to garden beds.
  • Pumpkins and winter squash should have hard rind before harvesting.
  • 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.
  • No need to worry about white pine trees that naturally drop many of their interior needles in fall.
  • Avoid severe pruning now if possible. Wait until February or March for most trees and shrubs. Spring bloomers should be pruned immediately after bloom.
  • Pick bagworms from evergreens. Pesticide sprays are not effective at this time. Spray with Bt products such as Dipel or Thuricide next year mid-late June.


  • Prepare soil now for a spring planting of 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.

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