IN THE GARDEN ORCHIDS NOT JUST SOME SHRINKING VIOLET.

Byline: JOSHUA SISKIN

If you were to compose a list of plants that flower nonstop during heat waves, you would probably not think of including orchids among them. Yet, lo and behold, strolling in my neighborhood a few days ago I came upon some glorious Epidendrum orchids growing in clay pots that were exposed to a good portion of the afternoon's sun. The inflorescences were globes of red-orange, yellow-orange or lavender and each consisted of geranium-like clusters of a dozen or so individual florets.

The toughness of orchids is not surprising when you examine their leaves, which are as leathery as those of many other kinds of succulent plants. Epidendrum orchids, although they appreciate sun and do not flinch in hot weather, require that their roots be kept cool, which means they should be mulched when planted in the garden.

In warm weather, epidendrums flower as relentlessly as any other nonstop bloomer, including lavender, lantana, bougainvillea and crown of thorns (Euphorbia millii). To be precise, the color you see on bougainvillea and crown of thorns does not come from flowers but from bracts, which are modified leaves.

Epidendrum literally means ``on a tree'' (epi=on, dendrum= tree) and was the original name given to all orchids when plants were first classified by the Swedish botanist Carl Linnaeus in the 18th century. Later on, orchids were divided into the many subgroups by which they are known today. In their tropical habitat, orchids live in trees, settling into trunk cavities or crotches of tree limbs, with roots either covered by rotting leaves and other jungle debris or completely exposed to the air. No roots demand better drainage than those of orchids, which is why orchid-growing media is composed of pieces of bark or pulverized volcanic rock. In the garden, epidendrum soil would ideally be a sandy loam mixed with some peat moss.

Q: Recently, I repotted my butterfly orchids after they bloomed. They get quite a bit of heat in the afternoon. Now their leaves look and feel OK, but are curling. What could be the cause?

-- Janice Hall, Lancaster

A: I am assuming that your butterfly orchids are Phalaenopsis types, also known as moth orchids, which are probably the most popular orchids around, their large flowers usually seen in lavender or white. Orchids produce pseudobulbs and -- in the manner of common garden bulb plants such as narcissus, tulip and lily -- have leaves that curl and dry up prior to abscission (falling off). As in the case of any bulb plant, you should allow orchid leaves to fall off on their own, since as long as they cling to the plant and have some green in them, they continue to manufacture food. In orchids, this food is sent down to the pseudobulbs, which are thus primed to produce new leaves and flowers in the next growth cycle of the plant.

Q: I recently mulched around a number of trees and plants with bark mini-nuggets. Now, there are hordes of ants in each of these mulched beds. Is there something in wood chips that ants eat?

What can I do to get rid of the ants without harming the trees and plants?

A: Ants move in response to changes in soil moisture.

You may have watered this area after a long period of dryness and that is probably what brought out the ants. There are a number of remedies for ants, including peppermint spray.

Make it by mixing one tablespoon of Dr. Bronner's peppermint soap or peppermint essential oil in two cups of water. Pour solution into a 16-ounce spray bottle and fire away.

As an aside, I have not seen any ants in my house or garden for two years. Has anyone had a similar experience? Does anyone know how to explain it?

One of the benefits of the blazing heat this summer has been the discouragement of fungus pests in the garden. This has been especially noticeable in the health of summer annuals, which are customarily smitten by flower, leaf and root fungus diseases.

Marigold flowers, since they consist of numerous nooks and crannies, normally dry out with difficulty after morning irrigation and, as a result, turn brown or black with fungus. This year, though, marigolds have grown into stout bushes without a trace of fungus.

Petunias often shrivel from root fungus attack, and annual vinca is most notorious for becoming instantly infested with leaf and root fungi that, virtually overnight, can utterly decimate the plant. This summer, however, due to the heat, there has been no excess water in the garden and so fungus has largely been kept out out of petunia and vinca plantings.

TIP OF THE WEEK: There is a new product called Perfectly Natural Weed & Grass Killer whose active ingredient is clove oil. It is quite an experience spraying weeds with a substance that smells so sweet. The product is a nonselective herbicide, which means that it should not be sprayed in lawns but used for eliminating annual and perennial weeds in flower or shrub beds and, of course, for those growing in sidewalk and driveway cracks as well.