September Gardening Checklist
- Dig and repot herbs growing outdoors, or take cuttings to pot up and grow indoors.
- Bring houseplants that spent the summer outdoors back indoors before night temperatures fall below 55 degrees. Some tropicals begin to suffer even when nighttime temperatures dip into the 40s, so don’t wait too long. Gradually decrease light to acclimate plants and help reduce leaf drop. Check for insects and disease before putting them with other plants.
- Begin stocking up gardening supplies before they are removed for the season from retailers' shelves. Pots, potting mixes, fertilizers and other products may be harder to find later in the season.
- Weeds like to perk up again in the fall. If it’s been three or more months, reapply Preen Garden Weed Preventer in your gardens and around trees and shrubs. Preen will prevent new weed seeds from sprouting this autumn. In the south, apply Preen Weed Preventer for Southern Gardens.
- Dig and divide perennials that are growing beyond their assigned spaces – or ones that are dying out in the middle. Discard the dead centers and replant divisions from around the perimeter. Fist-sized pieces are fine. The exception: perennials that bloom in fall, such as mums, sedums and asters.
- Stop pruning and fertilizing trees and shrubs. This is the beginning of their slow progression into winter dormancy. Don’t “confuse” them by doing things that trigger growth while their genes are attempting to regulate the opposite.
- Don't be alarmed if evergreens, especially white pine and arborvitae, drop needles. All evergreens shed needles at some time, but not all at once like deciduous plants do.
- Plant container-grown or balled-and-burlapped nursery stock. Apply Preen Mulch Plus to help retain soil moisture, moderate soil temperature and keep weeds from sprouting. Keep newly planted stock well watered until the ground freezes.
- Continue watering gardens, shrubs and trees if rainfall doesn't reach an inch or more every week or 10 days. It's important for plants to go into cold weather with adequate moisture.
- Plant, transplant or divide peonies, daylilies, poppies, iris, phlox and other summer-blooming perennials.
- Order spring-flowering bulbs or purchase locally. Begin planting them at the end of the month. Planting too early can cause top growth to sprout before winter; allow four to six weeks for good root formation before ground freezes.
- Dig tender bulbs, such as cannas, caladiums, tuberous begonias and gladiolus, before frost. Air dry and store in dry peat moss or vermiculite.
Photo courtesy Netherlands Flower Bulb Information Center