Q. I am sure many gardeners are trying plants that are less than hardy. I wonder if they have tried any of the many antidesiccants, and with what results. Here in Colonial Williamsburg we have had our best results with Vapor-Gard and Wilt-Pruf on evergreens.

A. The needles and leaves of evergreens give off moisture during winter months, and the water loss is greatest during periods of strong wind and temporary periods of sunny, naild weather.

During severely cold weather when the ground is frozen beyond the depth of the root system, the roots cannot get moisture to replace that which has been lost, and desiccation occurs.

Antitranspirants (also called antidesiccants) are chemicals that reduce the loss of water. Sprayed on plants, the film acts as a barrier to prevent water loss. Apply the spray to all the above-ground parts of the plant and cover both lower and upper leaf surfaces. Follow label directions carefully.

Allow the film to solidify properly and avoid wetting the foliage for about six hours after application. Usually one application is adequate for the winter season.

There are reports that in many cases both Vapor-Gard and Wilt-Pruf fail to solidify completely. A new product, Wilt-Pruf NCF, is said to be superior. The materials emulsify more readily if mixed in lukewarm water. As with all chemicals, label directions should be followed closely.

These chemicals may permit survival of some plants of marginal hardiness. Yet there appears to be little proof one way or the other.

According to the Landscape Contractors Association of Metropolitan Washington, risk is inevitable if one wants to grow winter-tender plants. Antidesiccants afford a small amount of protection, but not under extreme conditions.

A heavy mulch (five or six inches), shading from sunlight and wind barrier are known to be highly beneficial.

Q. Can a large camellia bush be transplanted? It is surrrounded by large azalea bushes at present.

A. The camellia can he transplanted successfully, but it should be done carefully. First, prune the roots by using a garden spade, going one-fourth around the plant. In about three months, go another one-fourth, in another three months do another one-fourth, and three months later do the last one-fourth. This will permit the plant to be moved with a fairly good root system in a ball of dirt.

Camellias are dormant during their season of bloom and this is a good time to rtransplant them. In rather mild climates it is better to transplant in the fall, and in colder areas it is better to do it in early spring just before new growth starts.

Make certain it is not planted deeper than it was growing before. Make allowance for it to settle in the new location, at least two or three inches. There will be no flowers if the plant is even an inch too deep, and the plant may die if it is more than that.

Q. Five years ago I planted a hydrangea in my garden, but it has never bloomed. What could be the cause?

A. One reason for failure of hydrangea to bloom is improper pruning. The growth that produces the flower buds develops in late summer. If the plant is pruned between early September and bloom-time, there will be no flowers that year.

Another reason is too much shade. Although these plants tolerate considerable shade they do not bloom.

Still another reason could be winter damage to the flower buds.

Q. Is there anything I can use to get rid of slugs without risk to our dog and the birds?

A. Get rid of the places where they hide. Slugs are snails without a shell and they must have damp places to stay during the day, such as under boards and other trash around the garden.

Placing tin pans of stale beer around the garden also may be helpful. They go after the beer, fall into the pan and drown.

Q. In 1975 I noticed that two of my daffodils showed nematode damage. I immediately dug the bulbs and destroyed them. Again in 1976 I noticed that several bulbs were damaged and I destroyed them. This year the damage appears more widespread. Should I have my soil treated?

A. Only an expert mematoligist can determine whether damage was caused by nematodes and indentify the species.Odds are the damage was not cue to nematodes. Your first step is to arrange with your county extension agent to have your soil checked.