THE VIRGINIAN-PILOT 
              Copyright (c) 1996, Landmark Communications, Inc.

DATE: Sunday, March 10, 1996                 TAG: 9603080107
SECTION: HOME                     PAGE: G3   EDITION: FINAL 
SOURCE: BY ROBERT STIFFLER, GARDENING COLUMNIST 
                                             LENGTH: Medium:   61 lines

WE LIKE RHODODENDRONS BUT THEY DON'T LIKE US

HAVING TROUBLE growing rhododendrons? My advice for the last several years has been to grow hydrangeas instead. Hydrangeas can be white, pink, purple, blue or red, with the use of soil additives.

From 50 feet away, your neighbors can't tell whether you have rhododendrons or hydrangeas.

But garden diehards still insist on trying to grow the beautiful but difficult rhododendrons. And garden centers sell them by the dozens every spring.

Dot Wilbur at the North Carolina Botanical Garden says that lilacs and rhododendrons come from cooler climates, which is why they are difficult to grow in this area.

If you insist on trying, she recommends planting rhododendrons on a north-facing slope. This protects them from the heat of winter sun. If the ground is frozen and the rhododendron is in bright sun, water will continue to transpire from the leaves, even though none is available to its root system. When the plant dries out, its chances of survival are greatly reduced. On a north-facing slope, it will maintain a more constant temperature and reduced rate of transpiration.

For rhododendrons and other broad-leaved evergreen shrubs, spray in the fall with Wilt-Pruf or Cloud Coveron. That may help such plants survive.

In late fall, plants change the contents of their leaves and stems. Substances called hydrophyllic colloids increase in the cells of evergreen leaves. Think of it like the antifreeze you put in your car's radiator. If we have a late, mild fall, these colloids don't have a chance to build up in the plant. If there is a sudden hard freeze, the watery, diluted solution in the plant's cells freezes and, just as in your car's radiator, the cells burst and the plant is ruined.

This can happen even if you mulch heavily early in the fall, when the soil temperature is still warm. By preventing roots from cooling, the hardening process is delayed. Then the top part of the plant is frozen when a hard freeze hits.

When asked their recommendations for mulch, several experienced horticulturists say their number-one choice is shredded pine bark, followed by pine needles.

Other plants that often don't make it through the winter include fig bushes, gardenias, daphnes, ginger lilies and silver dollar eucalyptus. They originally came from warmer climates. Mulching these plants will help them survive.

If you wish to grow a plant that is marginally hardy in our area, Wilbur says, plant it in a site protected from extremes of temperature, light, wind and water. For a rhododendron, that means on the north side, where early morning sun does not hit it.

If unsure about where to plant a shrub or tree around your home, choose a native plant. They grew up here, so they're adapted to the climate. Certified Virginia or North Carolina Nurserymen in garden centers also can advise you.

KEYWORDS: WEEDER'S DIGEST by CNB