Roses rewarding, though temperamental

In 1986, the rose became the national flower of the United States. It's also the official blossom of Georgia, Iowa, New York, North Dakota and Washington, D.C. - making it most popular choice for a state flower. But this popularity is somewhat curious, as gardeners know roses are fraught with disease and insect problems.

With proper cultural conditions, roses offer beautiful flowers. We have had those conditions so far this spring: low humidity, cool temperatures and ample rainfall followed by drying winds to discourage fungus. And roses had great snow cover for winter protection this year. You can build on this optimal setup by following these cultivation practices so that roses remain healthy - and flowering.

• Give them the best soil. Roses thrive in a light-textured, friable planting medium. Dig the planting hole to a minimum of two feet deep and wide. Then mix two-thirds native soil to one-third compost or manure in the hole. Remove the rose bush from the pot and set it into the soil mix, being careful not to disturb the small, wiry absorption roots. Place the rose so the roots are in the ground and the base of the trunk is at ground level. Be sure that grafted roses are planted with the graft scar above ground. Protect the plants with mulch in winter.

• Protect them from deer, which like to eat roses. Commercial repellents use animal products, such as putrescent egg solids, to make the plants unappealing to deer. Most repellents remain effective for about 30 days. Two products that I have tried with success are Liquid Fence and Deer Stopper. Deer don't like strongly scented plants, so mint and rosemary are deterrents, as are plants with fuzzy (tomentose) leaves. Installing a deer fence is another option.

• Water carefully. Roses prefer moist, deep, well-drained soil. Keep water from splashing onto the leaves of the plant to control leaf fungi.

• Prune roses before growth begins in spring. Cut out old canes with thick stems and all deadwood. Clean pruners with bleach after using them to cut dead or diseased wood, before you use them on healthy canes. Lubricate pruners with light oil to discourage corrosion.

• Add a fresh layer of ornamental mulch only after you have removed the old mulch. One to two inches of decorative mulch is all you need. Too much can impede air and water penetration.

• Spread an organic rose fertilizer around the base of the plants once a year, in spring. Espoma Rose-tone is one commercial product with a good balance of nutrients. Many rosarians have their own organic recipes; fish, banana peels, dried alfalfa and liquid kelp are a few.

Thousands of rose varieties have been bred over thousands of years. Even the latest hybrids were introduced from about 12 original species. Rose breeders can produce almost any characteristic they desire. The line between categories blurs with each introduction. The greatest difference among them is flower, color, length of bloom and plant size.

For more information on rose care, locating special varieties, or other questions, contact the American Rose Society (Ars.org).

• Joel M. Lerner is president of Environmen-tal Design in Capitol View Park, Md. info@gardenlerner.com.