Fall is prime planting time for spring-flowering bulbs and your best opportunity to establish and expand perennials gardens that will give you four-season color.

Ornmental grasses also give gardeners some of the best excuses to look forward to the end of summer. Their plumes and willowy ways are charming chums when summers flowers fade.

So get off the couch and head out to check the bins of bulbs and their perennial companions at your favorite garden center:

BEST BUDDIES
Bulbs and perennials are becoming best buddies in the garden, says the Netherlands Flower Bulb Information Center (www.bulb.com). You can mix and match them in early-, mid- and late-blooming varieties to have color any time you step out the door.

For good color combos, plant blue lungwort, Pulmonaria angustifolia, (named because it was once thought to have medicinal use for the lungs) with the later-flowering pale yellow Narcissus Jenny. Both like semi-shade and tolerate moisture.

A planting of Hosta tardiana Halcyon is quite striking against Muscari Blue Spike or Fantasy Creation. The early, long-flowering miniature Narcissus February Gold looks good with Forsythia intermedia Golden Bell. Primroses also make eye-catching companions for early-blooming bulbs.

And there's nothing lovelier than bulbs, especially miniature daffodils, planted among ground covers such as ivy, ajuga and vinca minor. Look for mini daffodils such as Baby Moon, Tete-a-tete, Little Gem and Hawera.

In other daffodils, look for doubles such as Golden Ducat, all yellow; Ice King, white with white and yellow ruffled center; Rosy Cloud, creamy white with salmon pink center; Tahiti, yellow with orange-yellow center. New ones include Lemon Beauty, white with white and yellow split cup; Palmares, white with peach split cup.

Remember, there's a practical side to all this combo planting: the ongoing foliage of the perennials will hide the ugly, drying foliage on the bulbs.

Locally, look for some of these new perennials for a start on your '99 gardens:

* Hibiscus Davis Creek with black-green leaves, mahongany stems and hot-pink flowers.

* Salvia Wild Watermelon with watermelon-pink flowers.

* Hardy Geranium Wlassovianum, blooms spring to fall, heat tolerant, foliage turns red in fall, blue violet flowers.

* Lobelia x speciosa Fan-Orchid Scarlet, partial shade, medium green leaves with reddish tinge, scarlet flowers. ``Nice even when not blooming,'' says Ann Weber of Smithfield Gardens.

* Echinacea paradoxa, U.S. native coneflower with yellow petals and dark center, sun to part shade.

* Lycoris radiata, spider lily in orange looks great with purple fall-blooming perennial ageratum, Eupatorium coelestinum, says Ann.

* Fall is the very best time to plant peonies. Miss America is an American Peony Society Gold Medal winner.

TRY ORANGE TULIPS
Tired of red and yellow tulips? Try some of the oranges coloring the bulb market this fall. You'll enjoy the fresh look they offer.

In areas where winters are mild, tulips should planted later than other bulbs. Plant them when the soil temperature has cooled to 60 degrees Fahrenheit, says Carol Chewning of Norfolk Botanical Garden. Planting tulips four times the depth of their size - 8-10 inches - will help them perennialize, or return year after year.

You can buy your tulip bulbs now and keep them in a ventilated bag - paper, mesh or holey - in the fridge at 40-45 degrees F. for six to eight weeks and then plant them. Remove ripening fruit in the fridge, especially apples, because fruit gives off ethylene gas which kills the flower inside the bulb.

When shopping, look for these orange-rich varieties suggested by the Netherlands Flower Bulb Information Center:

* Among the more aromatic tulips are Tulipa Orange Sun, T. Bellona and T. Christmas Marvel.

* Prinses Irene - soft orange flushed with purple in an unsual coloration. Rich in fragrance; 12 inches; it makes an excellent cut flower and can be grown in pots.

* Orange Emperor - an early 18-inch tulip with a salmon-orange exterior with deeper orange interior. It offers a large flower and blooms early.

* General de Wet - rich orange; fragrant; 13 inches.

* High Society, Triumph - reddish-orange edged in pure orange; 18 inches.

* Orange Sun - pure bright orange; 20 inches.

* Little Princess - late-blooming, pure orange with black center edged in white; 4 inches.

* Ballerina - golden marigold-orange, fragrant; 22 inches.

* Temple of Beauty - salmon rose; 30 inches.

Other relatively new colors in tulips:

* Greenland - green tulip with rose or pink edge; long flowering.

* Portifino - mid- to late-bloomer, creamy white flamed with red and a touch of red on edge of petal.

And while orange is the rage now, the color purple waits in the wings to be the next fashion statement in the garden. Purple and orange are natural color mates.

LATE-BLOOMING PERENNIALS
Perennials for late summer and fall: Eupatorium purpureum, Joe-Pye weed; Campanula pyramidalis, chimney bellflower; Liatris pycnostachya, cattail gayfeather; Solidago canadensis, Canada goldenrod; Rudbeckia fulgida, showy coneflower; Aster spectabilis, seaside aster; Stokesia laevis, stokesia; Hosta plantaginea, white plantain-lily; Aster tataricus, Tartarian aster; Chrysanthemum serotinum, giant daisy; Salvia azurea grandiflora, Great Azure sage; Helenium autumnale, common sneezeweed; Kniphofia uvaria, common torch; Anemone x hybrida, Japanese anemone; Chelone lyonii, pink turtlehead; Salvia patens, Gentian sage; Sedum spectabile, showy stonecrop; Anemone hupehensis, Japanese anemone; Echinacea purpurea, purple coneflower; Aster novae-angliae, New England aster.