BY THE MIDDLE of December the garden has lapsed into dormancy, and even though the calendar says late autumn, the view out the window says dead of winter. There is no better antidote to this dearth of color than the bright pink of cyclamen, the traditional red of poinsettias, the sweet scent of paperwhites.

Plants have long been part of holiday traditions - mistletoe for romance, holly as a charm against evil spirits. It seems part of human nature to celebrate with plants, to gather living things inside during the darkest days of winter. You don't need the skills or patience (let alone time) of a Martha Stewart to best care for holiday plants. The old "right plant, right place" adage works inside, too, for keeping plants healthy.

I admit I used to consider poinsettias (Euphorbia pulcherrima) tacky, thinking of a single droopy plant encased in shiny foil. Poinsettias call out for grouping - think of a whole flock of pink or pearly cream poinsettias in terra-cotta pots, or a bright red poinsettia nestled into a copper urn, surrounded by ferns and variegated ivies. Poinsettias now come in an amazing array of colors, which can make it hard to choose among them. All the shades, from white through palest marbled peach to dark, rich red, look just right with the deep green of boughs cut and brought inside from the garden.

Keep poinsettias fluffy and their green leaves green (the "flowers" are just colored leaf bracts) by keeping them out of drafts and cold. Remember that poinsettias are native to Mexico, so they thrive in a warm house. Give them at least six hours of bright indirect light each day, water thoroughly when the top inch of soil dries out, and you will have a fine display of poinsettias until you grow sick and tired of them as we come up on Easter.

For a cooler spot in the house, go for the more delicate charms of cyclamen, with their marbled leaves and butterfly-winged flowers. Less traditional than the ubiquitous poinsettia, cyclamen come in pure white, lavender-pink, and warm rose shading into red. The clustering heart-shaped leaves are patterned with varying degrees of shimmery silver. The little buds droop like shy flamingos as they poke up through the exuberant foliage, promising flowering that will last for months. Cyclamens will bloom longer if kept cool, with plenty of humidity and moist but not soggy soil.

Christmas cactus (Schlumbergera) are perhaps the easiest of all the holiday plants, and are often passed down through generations as they can live for years and years root-bound in the same pot. These sprawling, flat-leaved, loose-jointed bloomers are especially pretty in the less common, paler shades. Normal indoor temperatures, bright light, porous potting mix and infrequent waterings keep these undemanding plants happy and in bloom. They prefer to summer outdoors (don't we all?), and need cool temperatures and darkness in the fall to bring them into flower.

While Christmas cactus are homey and familiar, a graceful spray of moth orchids is sheer elegance. Place a single stem of vivid, splotched and freckled Phalaenopsis in a pretty pot or gilded basket, add a couple of candles, and you're done decorating. Despite their look of classy exoticism, Phalaenopsis orchids do well in normal indoor conditions; provide bright light, high humidity, keep the plant moist and its flowers will unfold, one after the other, through the winter months.

And if you haven't yet forced a pot of paperwhite narcissus, there is still time to bring them into bloom by New Year's, as they don't require a period of dark and cold like other bulbs. Fill a pot with dirt or pebbles and squeeze in as many as you can. As the stems develop, wrap them with a pretty ribbon for support, and once they start to show color, stick them outside at night (as long as it isn't freezing) to make them last. You'll have a display reminiscent of springtime and as fragrant as the tropics just when you need it the most.

Valerie Easton is a horticultural librarian and writes about plants and gardens for Pacific Northwest magazine. Her e-mail address is vjeaston@aol.com Benjamin Benschneider is staff photographer for Pacific Northwest magazine. ------------------------------- Now in Bloom: Dwarf Hinoki cypress (Chamecyparis obtusa `Nana Gracilis') is ideal to grow in a pot or in a mixed border, since it grows only a couple of inches each year, topping out at 4 feet. Just be sure to grow it where it is easily reachable, as it is hard to resist running a hand over its soft, fan-like, twisted needles.