Magnolia scale an easy-to-find nuisance

We at the Chicago Botanic Garden are noticing more magnolia scale(an insect) than in previous years. Look closely for these insects,which are about the size of a pencil eraser, on the branches of yourmagnolia tree--typically on the underside.

Other easy-to-spot signs include an overall thin condition of thetree and a black, sooty mold on the leaves of the magnolia and anyplants under the tree.

Magnolia scale exudes a substance called honeydew when feeding onthe plant. Black sooty mold is a fungus that grows on this substanceand is only a cosmetic problem.

STEP ON IT. For small trees or infestations, simply pick off themagnolia scale and squash it. Other control measures include treatingwith a summer weight oil or an insecticide when the scale is in thecrawler stage (small, immature and vulnerable), generally in earlySeptember.

For trees with a history of scale, apply dormant oil in the earlyspring as a wise preventative. If your tree is affected, provideextra watering during the summer to minimize stress.

WATERING EVERGREENS. Make sure the rootballs of newly plantedevergreen trees are thoroughly moistened when watering. Denselybranched evergreen trees can shed water from rain or a sprinkler awayfrom the rootball. Apply water to the base of these trees.

WELL GROOMED. Continue to groom your perennials and annuals byremoving yellowing foliage and spent flowers. Make note of perennialsthat have flopped and need staking so that a support system can beinstalled next spring before the plants actually need it.

VERSATILE SEDUM. Sedum or stonecrop is a large group of lowsucculent plants that can have many uses in the home garden. Theflowers range in color from white, yellow, pink and red to purple.

They can be easily divided at almost any time of the year, andcuttings or broken stem pieces root readily. Most sedum are goodplants for poor, stony soil in the hot sun between stepping stonesand in rock crevices.

PLANT SHOWS. The Chicago Botanic Garden hosts the Illinois RoseSociety Show & Sale, featuring modern hybrid tea roses, grandiflorasand floribundas, old garden roses and shrub roses, from noon to 4:30p.m. today.

Also, don't miss the Dahlia Cut and Bloom Show and Sale and theGarden Clubs of Illinois, District IX Standard Flower Show on Sept. 6-7. For information, call (847) 835-5440 or visitwww.chicagobotanic.org.

Tim Johnson is director of horticulture at the Chicago BotanicGarden. For more information, call the plant information line at(847) 835-0972, or visit the Web site at www.chicagobotanic.org