As late summer becomes early fall, it is a great time to get outside and do some yard work. Get tips on great ways to improve the yard, trees, garden and flower beds from Iowa State University Extension and Outreach horticulturists. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
Mid-August through September is an excellent time to plant pine, spruce and other evergreens. (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 can be planted from August through early November.
Water newly planted trees every day for three or four days and then gradually reduce the frequency of watering. When watering, slowly apply water to the rootball and the surrounding soil. A thorough watering every seven to 10 days (in dry weather) should be sufficient three to four weeks after planting. Continue watering until the ground freezes.
Late summer/early fall is an excellent time to plant many perennials. It also is 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 several inches of straw, pine needles or other materials in late fall. Mulching helps prevent repeated freezing and thawing of the soil that may heave plants out of the ground. Drying of exposed plant crowns and roots can cause severe damage or death.
Mid-August to mid-September is the best time to seed new lawns and overseed existing lawns in Iowa. Late-summer 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 fall.
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 is not frozen.
For a fall crop, plant leaf lettuce and spinach in mid-August. Radishes can be planted from mid-August to mid-September. October is the best time to plant garlic in Iowa. Plant cloves one inch deep with the pointed side up. To prevent winter injury, cover garlic with a 4- to 6-inch layer of weed-seed free straw. In early spring, move the straw to between the rows to allow the garlic foliage to emerge.