The big harvesting month is also the big watering month

Sunset, August, 1987

The big harvesting month is also the big watering month

August is glory time for many plants inmountain gardens: fruits and vegetables are ripening, flowers are blooming. But summer weather can be at its toughest on plants this month, too. Keep everything watered so that vegetables and fruit mature properly, flowers keep blooming, and lawns stay green.

Summer rains may help, but when plantsdo need irrigation, water efficiently. Spread mulch around plants to conserve moisture, and water deeply but infrequently. Avoid wasteful runoff by building soil basins that direct water to roots.

Don't overwater lawns; latest researchshows most intermountain lawns can get by on less than 1 3/4 inches of water a week in August. Measure your sprinkler output by placing five straight-sided containers randomly around your lawn and turning the system on for 15 minutes.

Hardy Siberian iris--a good plant to remember this month

August is the month to order or plantbulbs and bulblike plants. One dependable high-elevation bloomer is Siberian iris (I. sibirica). This native of frigid Siberia thrives at high elevations, quickly naturalizing and forming thick clumps that seldom need dividing.

It blooms mid-May into June, afterbearded iris have faded. Blue, purplish, or white flowers cap 2- to 3 1/2-foot stems above clumps of grassy green leaves 1 to 1 1/2 feet tall. They resemble Dutch iris and make excellent cut flowers.

Plant Siberian iris in full sun, in well-drainedsoil rich in organic matter. Set the rhizomes near the soil surface and provide plenty of moisture during the growing season.

You may find Siberian iris for sale in 1-galloncans in some nurseries and garden centers this month, particularly in the Denver area. Or you can buy dormant rhizomes by mail. Two sources are Blackthorne Gardens (48 Quincy St., Holbrook, Mass. 02343; free catalog) and Wayside Gardens, Inc. (Hodges, S.C. 29695; catalog $1).

How do you know when to harvest corn so you get the best flavor?

In areas with a short growing season,gardeners usually don't have the luxury of successive vegetable plantings. And if the crop is corn, you want to make sure that you pick when ears are at peak flavor, because you won't get a second chance.

After corn matures, the sugars that givean ear its sweet flavor quickly turn to starch, making the corn taste milky. In some varieties, this can happen within 72 hours if the ear is still on the stalk (within 12 if it's been picked). Some newer supersweet varieties hold sweetness longer, but try to pick and eat corn as close to its maturity as possible.

Most corn is ready to eat about threeweeks after the silk emerges from the top of the ear, though this can vary from place to place. Once the silk dries and turns brown, test maturity by pulling back the husk and pressing your thumbnail into a kernel. If juice squirts out, the corn is edible. Eating it early is better than late.

If brown or green worms eat the top kernelson some ears, simply cut off the damaged part and eat the rest. Corn earworms, as they're called, seldom do serious damage--and control (repeatedly spraying or dusting emerging silk with carbaryl is most effective) is not very practical.

Summer pruning: pluses and minuses

Pruning in winter has advantages: whendeciduous plants are leafless, it's easier to see their structure and determine where to make the right cuts. But gardeners who live in cold-winter areas can get ahead by making some cuts now.

Summer pruning has a greater dwarfingeffect on a plant than does pruning during the dormant season. It also goes further toward keeping a plant smaller or restricted to a certain area. Summer pruning also allows you to direct growth and favor shoots that you want to select as permanent scaffolds (main structural branches).

This is particularly important when trainingyoung fruit trees. Simply pinch or remove branches that are competing with the shoots you want to favor.

Also, pruning now to open up the centerof a plant and increase light and air circulation may help prevent some diseases.

One drawback of summer pruning is thatif you do it too late, any new growth that occurs won't have time to harden off properly. Early cold can damage plants normally considered hardy. If you're going to do light summer pruning, do it before mid-August.

Photo: Bright blue blossoms of Siberian irismake a stunning spring show atop clumps of grassy green foliage