Late Summer and Early Fall Planting
While spring is the traditional planting season in Iowa, late summer/early fall is an excellent time to plant trees, shrubs, perennials, and spring-flowering bulbs. Late summer to early fall also is the best time to establish a lawn from seed.
Home gardeners can begin seeding of lawns in mid-August. Seeding should be completed by mid-September in northern Iowa. Gardeners in southern Iowa can sow grass seed up to October 1. A late summer to early fall seeding has several advantages over spring seeding. The seeds of cool-season grasses germinate quickly in the warm soil of late summer. The warm days and cool nights of early fall promote rapid turfgrass growth. The growing grass also has less competition from weeds as few weed seeds germinate in the fall.
A new lawn also can be established by sodding. The best times to sod are spring and late summer/early fall. In fall, sod can be laid until the ground freezes or is covered with snow.
Trees and Shrubs
Balled and burlapped and container-grown trees and shrubs also can be planted in late summer and fall. Mid-August through September is an excellent time to plant evergreens, such as pine and spruce. Evergreens planted in late October or November may not have adequate time to become established before the onset of winter and could be subject to desiccation injury and death. Deciduous trees and shrubs (those that drop their leaves in the fall) can be planted from August through early November.
While most trees and shrubs do well when planted in late summer or fall, some woody plants are slow to establish and are best planted in spring. Trees that are best planted in spring include fir, birch, yellowwood, ginkgo, magnolia, ornamental pear, oak, and hemlock.
Trees and shrubs planted in late summer or fall should be watered every 7 to 10 days during dry weather. Continue watering until the ground freezes.
Late summer/early fall is an excellent time to plant many perennials. It is also a good time to move or divide perennials, such as peony, daylily, garden phlox, and Oriental poppy. Perennials planted in late summer or early fall should be mulched with 4-6 inches of straw, pine needles, or other materials in late fall. Mulching helps prevent repeated freezing and thawing of the soil that can heave plants out of the ground. Drying of the exposed plant crowns and roots can cause severe damage or death.
October is the ideal time to plant tulips, daffodils, and other spring-flowering bulbs. Plant bulbs in groups or clusters to achieve maximum visual impact. Bulbs planted individually or in single rows are generally not as effective. Spring-flowering bulbs can be planted as late as December if the ground remains unfrozen.
Late summer/early fall is time for gardeners to enjoy the fruits of their labor over the past several months. It's also time to plan and plant for the future.
This article originally appeared in the 8/22/2003 issue.