
DATE: Thursday, July 17, 1997               TAG: 9707170511

SECTION: FRONT                   PAGE: A17  EDITION: FINAL 

SOURCE: ROBERT STIFFLER
                                            LENGTH:  120 lines

AFTER COLD SPRING, DRY HEAT BESETS GARDENERS

After the coldest, nastiest spring in recent history, gardeners now are hit with horrible heat and almost no rain.

That means spider mites wrecking our flowers; Japanese beetles spoiling our roses; tomatoes with blossom-end rot; azaleas dying; dogwoods with mildew; grass that looks like straw.

What's a gardener to do?

Don't give up. We gardeners are like farmers. If we wanted the easy life, we would have quit eons ago.

Here's some help solving your lawn and garden woes:

Blossom-end rot on tomatoes. It's prevalent now, but can be corrected with a calcium spray available in garden centers. This fall, put a cup of lime in each spot you plan to place a tomato next year. Early next spring, mulch your tomatoes with bark, pine straw, grass clippings or whatever is handy. If you mulch early, you can prevent blossom-end rot.

Dying azaleas and camellias. This is a tough one. Azaleas die limb by limb, and the problem can be caused by spider mites, azalea lace bug, voles, dry weather or a combination. Cygon, diazinon or malathion will control the lace bugs and spider mites. If you see quarter-sized holes around the plant, put Ramik in the holes to prevent voles from eating the roots.

Azaleas need an inch of water per week, so make sure they get that. Linda Pinkham of Smithfield Gardens suggests applying a drench of root stimulator once or twice a week. It's available at most garden centers.

Camellias are tougher than azaleas but may suffer the same problems. Check your camellias and use the same remedial action if necessary.

Other shrubs. The most you can do is keep them watered, giving them 1 inch of water per week. Give preference to shallow-rooted plants such as azaleas. Prune any branches you're sure are dead. Shrubs under large trees are experiencing the most stress, because the larger, more dominant trees are sucking up the water.

Don't do any severe pruning, because it makes plants want to grow new foliage to replace the old. They do not need that kind of stress in this kind of weather.

Many shrubs at entrances to subdivisions and public facilities are dying, because they can't be watered regularly. In October, these plants will need to be replaced.

Crape myrtles. They are showing mildew, and suffering much in the drought. If mildew is a problem, you can spray with a fungicide like Immunex. The best solution is to pull out the plant this fall and replace it with a new mildew-resistant variety.

Trees. Weather is causing leaves of many trees to turn brown at the edges, particularly on dogwood and Japanese maples. Water trees as much as you can, up to 1 inch per week. Trees are tough, so if they have a good root system, they'll survive. But give them proper attention, because trees grow slowly and usually are expensive to replace.

Grass. Grass should get the least attention, because it is the easiest and quickest to replace. Water when you can, but it will recover quickly with this week's rain.

When you mow, set your lawn mower blade at the highest setting and let the clippings fall on the lawn. Douglas Fender, director of The Turf Resource Center, notes that fresh lawn clippings are made up of 80 percent to 90 percent water. Cut the grass frequently, so no more than one-third of the blade's length is removed in a single mowing.

Spider mites. These tiny, life-sucking mites attack many plants in hot, dry weather, especially roses, foxglove, butterfly bush, tomatoes and green beans. This season, they've picked on plants with grassy, spear-like leaves such as daylilies and crocosmia (also called montbretia).

Richard Sterrett of Sterrett Gardens, a major daylily grower on the Eastern Shore, says they've had to spray to protect their plants, but he cautions that being ``sanitary is a must.'' Cut off all brown foliage just above ground level and destroy it. Feed the plants lightly with a long-lasting fertilizer and water thoroughly.

Gardener Kendall Eakes, who propagates boxwood, told me last week many of his boxwood had started turning yellow, and he discovered they were infested with spider mites. He sprayed with malathion. Virginia Tech's manual recommends Kelthane and Vendex.

Entomologist Peter Schultz, director of the Hampton Roads Agricultural Research and Extension Center, says the two-spotted mite is causing all the damage. The recommended control is spraying once a week with malathion, diazinon or Cygon. It's important to thoroughly wet all foliage with your spray.

Do not use Sevin powder. Research shows that Sevin helps spider mites multiply more rapidly.

For an organic spray, use pyrethrin or rotenone. Insecticidal soap is also sometimes recommended. Some organic publications recommend summer oils, but I would not use them in hot weather.

You can knock mites off foliage with a strong spray of water. There also is a new organic garlic spray on the market called Garlic Barrier, labeled for spider mite and white-fly protection. I'm planning to apply it with a hose-end sprayer over my entire lawn and shrubs this week.

Check your boxwood and any shrub or plant that has yellowing foliage. Speckling of the leaves is a sure sign of trouble. As long as hot, dry weather continues, spider mites will be a severe problem.

Japanese beetles. Fortunately, they've not been as bad as usual, but are beginning to show up. Sevin or Orthene is the product most often used for control, or pick them off by hand and drop them in a can of oil.

White flies. They will probably be the next enemy, especially on gardenias and tomatoes. Yellow sticky traps work well for controlling white flies.

If you use chemical sprays, Virginia Tech recommends treating weekly with resmethrin, Pounce, Dursban and Thiodan.

With all sprays, whether chemical or organic, read and follow directions carefully.

And don't overwater. You can drown a plant if it does not have good drainage, so make sure your plants have that.

Richard Sterrett reminds me that a couple of years ago, we'd had our first hurricane by now. It dropped 8 inches of rain. Which is preferable? Tough question. ILLUSTRATION: Photo

LAWRENCE JACKSON/The Virginian-Pilot

Bob Green of East Ocean View waters the flowers and lawn of a friend

in the Hampton Gardens section of Norfolk. Green has been watering

with greater frequency during the recent hot and dry weather.

Graphic

HOW MUCH

Most plants need 1 inch of water per week. How do you know when

you've applied that much? Put a coffee can 10 to 12 feet from your

sprinkler and measure. At the 1-inch mark, you've watered enough.

Shallow watering draws roots to the surface and can do more harm

than good.