LANGFORD: Roses need your help now

Published August 11, 2007 at midnight

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More dig!

Roses are on their way to re- bloom for a final go-around now that cooler days and nights are around the corner and fall considers it's time to begin showing up. For the next couple of weeks, follow the steps below to give your roses the best chance to perform.

• Diseases: The most common disease problem this time of year is powdery mildew. Leaves start to pucker, then a whitish-gray growth appears on them. As the disease worsens it looks like rusty kitchen flour has been sifted over the plant. There are excellent fungicides - Ortho, Fertilome - available at garden centers that will help the problem.

Black-spot, as the name implies, shows up as black spots, while Rust appears as brownish or orange discolorations. Sulfur products, or Neem fungus control, work on these problems as well as the previously mentioned controls. Once these diseases are well-established, they are hard to stop. Your best bet at this time of year - and in advanced stages - is to prune out and remove the worst of the damaged foliage.

The organisms causing these problems are all around us in the air. Good cultural practices can reduce much of the damage. This includes eliminating watering from above - sprinkling - and instead soak at the ground level. Keep plantings far enough apart to allow for good air movement and remove old garden residue and dead stems. A good mulch, like chunk bark, around the roses also helps. Mulch keeps organisms in the soil from splashing up on the plant, keeps roots cooler during the hot season and allows for easier water penetration.

• Chlorosis: Many roses, and other perennials, are showing the results of a lack of available iron. Check for light green leaves with the veins showing a dark green. Sometimes the new growth will be so anemic it will be almost white. It's relatively easy to correct the problem. One-half cup of Liquid Iron or Revive in a half-gallon of water and poured, then watered in, around the base of the plant will usually do the trick. Pour in a circle about 5 inches out from the base of the plant. If the pale green leaves don't start to green up in a week, apply a second application.

• Water-feeding: While on the subject of watering, you should deep water your roses every 10 days for two or three more waterings. After that, cut back on the moisture to begin hardening off the plants for winter. If the hot spells continue, alter the plan.

It's probably too late to apply full feedings of plant food, other than iron. Other food would stimulate too much soft growth and retard the normal hardening-off process your roses go through as fall approaches. Some folks use a light application of foliage feeding as a late summer touch-up and that works just fine if the plants need a little shot.

• Leafcutter bees: Don't panic if you notice small round holes in the plants' leaves. The culprit is the leafcutter bee, which uses the cut-out parts to make nests; the damage causes little harm. Also keep an eye out for spent blossoms or damaged buds. Remove them and the energy that is being wasted on them will go to new blooms instead.

• Insects: This time of year, damaging insects include spider mites and aphids. Leaves will appear stippled from the thousands of small punctures made as these insects insert their mouth parts and suck out valuable sap. The leaves then pale and turn a speckled brown.

Check for spider mites by shaking a stem over a white piece of paper. If the small dust-like particles begin moving around, you have company. Aphids are tiny, but can be seen on the underside of the leaf and are usually a pale green. Rose dusts work well, especially those containing both insecticides and sulfur. If you use a dust that also contains a fungicide, you can do two jobs at once. If the bugs are not too many, try washing them off the plant with a strong shot of water from the hose.

A good program put in place now will be helpful not only this fall but next year as well. Your roses will be stronger, healthier and more productive in blooming for the next season. If your neighbor's rose garden makes you envious, that's a good sign you should get out and do some good work now in your own beds. Maybe next year you'll have him looking over the fence with envy.

Dale Langford is an area lawn and garden specialist.

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