September Gardening Tips




Many perennial flowers including peonies, daylilies and tall garden phlox may be divided in early fall.  Dig the old clumps with a spading fork and split the crowns into several pieces using a sharp spade or large knife.  Each new clump should contain part of the crown with several buds or “eyes” and a large part of the roots.  Prepare new planting areas by mixing in compost or peat moss and replant at the correct depth (eyes should be only 2” deep for peonies to bloom well).  Water well and mulch in late fall to prevent winter injury.


Apply water soluble fertilizer to your containers and hanging baskets to keep the plants healthy and blooming.


Daffodils planted this month will provide welcome color early next spring. Drifts of a dozen or more bulbs of one variety make the most impact and can be easily planted by digging the whole planting area 6”- 8” deep, space the bulbs according to the package directions, fill in the soil and water well.  Bulb fertilizer may also be incorporated below the bulbs.


Trees and Shrubs


Fall is a great time to plant trees and shrubs.  The new plants will have several months to grow new roots and will be ready to grow early next spring.  Consider adding some plants with great fall color such as sugar maple, ginkgo,  burning bush or the University of Minnesota hardy blueberries including ‘Northblue’, ‘Northsky’ and ‘Polaris’.


 Trees that bleed or are susceptible to disease if pruned in the spring may be pruned now.  This includes maples, birch, black walnut, oaks, honey locust and mountain ash. Prune young trees to a single central leader; remove broken, crossed or rubbing branches; and gradually remove lower branches.  Always make proper pruning cuts just beyond the branch collar but not leaving stubs.




September is the best month to control broadleaf weeds in your lawn. Dandelions, plantain, creeping charley and clover are cool season plants that are actively growing in the fall. Use an herbicide containing 2,4-D; apply according to the package directions and when temperatures are between 60 and 80 degrees.


Lawn grasses are cool season plants and late summer and early fall are the best times to start a lawn from seed.  The seed must come in contact with the soil either by tilling or vigorous raking prior to seeding or by using a slit-seeder that cuts slits in the old sod and drops the seed at just the right depth.  Several light waterings each week will get new lawns or re-seeded patches off to a good start.


  Fruits and Vegetables



Minnesota Grown apples will be ripening by State Fair time and are available at local orchards, fruit markets and grocery stores through mid-winter.  If you grow your own apples pick them just when the color and flavor peaks and while they are crisp and juicy.  Zestar! is a new University of Minnesota introduction that has great flavor and texture and keeps well for an early apple.  Honeycrisp is also a University of Minnesota release and is becoming nearly everyone’s new favorite apple.  Look for Honeycrisp apples after September 15.


Squash and pumpkins should be harvested when they have bright color and a thick hard skin. These vegetables will be abundant in farmer's markets and stores and make a colorful and healthy addition to fall dinners.