Gardening by Month - October

Trees & Shrubs

• Trees and shrubs can be planted for fall through November. Water thoroughly and provide mulch for winter protection.

• Be sure to adequately water plants, especially evergreens, if conditions are dry throughout fall. 

• If required, transplant deciduous trees once they have lost their leaves.

• Use tree guards around young trees to protect against animal damage over winter.

• Look out for clusters of honey-colored mushrooms near the base of trees, an indication Armillaria root rot is present.

• Peak fall color usually occurs in late October through early November. Now is the time to observe and choose nursery stock based on fall color.

• Mulch trees and shrubs using the "donut" method as opposed to the "volcano" method which can damage trees and cause roots to girdle.

• Leaf spots on trees may be noticeable, but no control is needed. Be sure to clean up and dispose of fallen infected leaves to reduce the chance of overwintering diseases. An example is tar spot on maples.

Annuals & Perennials

• As perennials start to die back, cut them down to about 1 inch above the soil level. Leave some natives up such as echinacea, rudbeckia, and helianthus, to provide a food source for wildlife during fall and winter.

• Plant daffodils and other spring bulbs by mid to late October. Tulips can be planted until the ground freezes.

• Spring bulbs can be planted among daylilies, ferns, hostas, and ground covers. As these plants grow in the spring, they will hide the dying bulb foliage.

• Non-hardy bulbs like dahlias, gladiolus, and cannas, should be dug up when the foliage is killed by the first frost, or when their leaves turn yellow. Clean off dirt and allow to dry under cover in an airy, frost-free place before storing. 

• Be on the lookout for fall color perennials with late-season blooms: New England aster (Symphyotrichum novae-angliae), goldenrod (Solidago spp.), and ornamental grasses.

• Spring bulbs forced for indoor bloom can be potted up now and stored in a cool, frost-free place until it is time to bring them indoors; usually 12-15 weeks. 

Fruit & Vegetables

• Plant garlic and shallot bulbs through October.

• Keep broccoli picked regularly to encourage additional production of side shoots.

• Persimmons start to ripen, especially after a frost. Best eaten when the fruit is mushy (many people harvest fallen fruit). If persimmons are underripe they will have a chalk-like taste.

• Continue harvesting fall crops. Be sure to harvest tender crops, pumpkins, and winter squash before the first frost. 

• Dig up sweet potatoes before a bad freeze.

• Some tender fall crops can be protected with a frost cover or row cover. 

• Keep an eye out for imported cabbage worm and cabbage looper. Handpick off or use an appropriate insecticide.

• Harvest gourds when their shells become hard or when the color changes from green to brown.

• Monitor fruit plantings for mouse activity and take steps for their control if they are present. Wire guards placed around the trunks of young fruit trees add protection against mice and rabbits.

• Harlequin bugs may be noticeable on cruciferous plants (such as cabbage and kale). These pests can survive on common weeds in the mustard family throughout summer. Handpick off and place in soapy water, or use an appropriate insecticide.

Lawns

• Seeding should be done by mid-October.

• Cool-season weeds may appear in lawns. Manually remove or use an appropriate herbicide.

• Continue mowing lawns as needed.

• Keep leaves raked off of lawns to prevent smothering grass, or mow over leaves to break them up into small pieces. Use fallen leaves as mulch for garden beds.

Miscellaneous

• Be sure to clean up plant debris to reduce the chance of fungal issues in the next year, as many fungi overwinter in leftover plant material.

• Seeds of woody plants may require 3 months of cold exposure in order to germinate. Plant these seeds outdoors in the fall or place them in the refrigerator for 3 months. 

• The average first frost date for St. Louis, MO, is October 15-20th. 

• Leave fallen leaves around your garden beds to supply local wildlife with food and habitats over the winter. The leaves will also provide some fertilization and weed suppression.

• Houseplants and other tropical plants should be brought inside by early to mid-October or before nightly temperatures reach below 50. Before bringing them in be sure to check and treat if needed for the following pests: spider mites, scale, whiteflies, mealybugs, and fungus gnats.