While spring is the traditional planting season in Iowa, late summer and early fall is an excellent time to plant trees, shrubs, perennials, and spring-flowering bulbs. Late summer and early fall is also the best time to seed lawns.
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 September 30. Late summer and early fall seeding has several advantages over spring seeding. The 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. For additional information on seeding a lawn, pick up a copy of Pm-1072, "Establishing a Lawn from Seed," at your local county extension office.
A new lawn can also be established by sodding. The best times to sod are spring and late summer/early fall. Fall sodding can be done until the ground freezes or is covered with snow.
Trees and Shrubs
Balled and burlapped and container-grown trees and shrubs can also be planted in late summer and fall. Evergreens should be planted from mid-August through September. Planting during this period allows the evergreens to become established before the onset of winter. Evergreens planted in late fall are susceptible 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 and fall, some woody plants root slowly and should only be planted in the spring. Slow-to-root trees that should be planted only in the spring include fir, birch, yellowwood, ginkgo, magnolia, ornamental pear, and hemlock.
Trees and shrubs planted in late summer and fall should be watered every 7 to 10 days during dry weather. Continue watering until the ground freezes.
Late summer and 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 and early fall should be mulched with 2 to 4 inches of straw in late fall. Mulching helps prevent repeated freezing and thawing of the soil that can damage recently planted perennials.
October is the ideal time to plant tulips, daffodils, and other spring-flowering bulbs. Plant bulbs in groups or cluster 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 and 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 August 11, 1995 issue, p. 121.