Trees, Shrubs, and Groundcovers

• Look for the flowers on Franklin trees Franklinia alatamaha this month. Solitary white, fragrant, 3-inch blossoms; showy fall color; and gray bark (often with vertical fissures) make this 10 to 20 foot tree an excellent landscape choice.

• The Oneida Viburnum, Viburnum dilatatum x V. lobophyllum 'Oneida,' a National Arboretum introduction, features summer bloom periods in addition to its May bloom time and showy, dark-red, fall fruits in addition to its fall foliage.

• Order peony roots now for planting in September. Plant about a month before the average first frost date in your area. Planting should be completed before the first killing frost occurs.

• Mulched shrubs may not develop mature stem tissue where they touch the mulch. To harden stems so they can withstand early frost damage, remove about 2 to 3 inches of the mulch from the base of the stems in mid-August.

• Avoid deep cultivation around evergreens that have roots near the ground surface so roots are not damaged.

• If azaleas look chlorotic (pale-green to yellow) check soil pH. They need acid soil because alkalinity locks up iron needed for green color. Sulfur reduces soil pH.

• If the leaves of euonymus turn yellow and drop, check the stems and undersides of the leaves for tiny, needle-like, white insects and a scattering of small, brown, shell-like shapes. This is euonymus scale (males are white; females brown). Climbing euonymus is more susceptible than most upright forms. Contact your local Extension office for approved control methods.

• Inspect trunks and branches of dogwood for injured bark or fine dust being pushed from burrows in trunks by borers. Contact your local Extension office for control recommendations.

• Keep newly planted trees and shrubs well watered.

• Clean up fallen rose and peony leaves. They can harbor disease and insect pests over the winter if allowed to remain on the ground.

• Root cuttings of woody shrubs and evergreens, such as azaleas, holly, and hydrangea, at this time of year.

• Leaf miner larvae tunnel inside leaves, leaving whitish trails as they move about. Holly, boxwood, and locust are particularly susceptible to damage.

• Powdery mildew diseases attack a great many ornamentals, most often in late summer when the days are warm and nights cool. Some mildews, particularly those on roses, apples, and cherries, also are increased by high humidity. Prevention by proper cultural techniques is the first defense. Grow resistant varieties; space and prune plants to improve aeration and lessen shading; water early in the day and at the base rather than on leaves; and reduce nitrogen applications to avoid excessive, late-season growth.

• Water shrubs deeply once a week during August. Many plants, including camellias and rhododendrons, are starting buds for next season's bloom at this time. Immature berries of hollies and pyracantha may drop if the plants are water stressed.