What do the people who garden for a living advise the working gardener who has just a few hours a week to devote to turning a yard into a garden?

* Carroll Clark, foreman of lawns and gardens at Longwood Gardens--Mulching is the biggest timesaver. It controls weeds and keeps the ground moist enough for you to ignore the garden for two or three weeks at a time. He recommends sheets of plastic, rotted leaves or newspapers covered with grass clippings.

Avoid glads, sweet peas and roses. For early color use yellow tulips with white pansies. For cut flowers on weekends: zinnias and marigolds.

* Cynthia Locks, a White House gardener--Wax begonias are the easiest summer plant; grass, the biggest waste of time. She helped dig up her mother's lawn and put in a design of mulch and white rocks that requires no mowing.

* Don Smith, superintendent of gardens and grounds at Dumbarton Oaks--Recommends begonias, coleus, impatiens and exacum (tiny blue or white flowers). For early spring: reticulata iris, snowdrops, crocuses and chionodoxa (Glory of the Snow). Once they're in, you can forget them and they'll come up year after year.

Also, daylilies, especially if you have children or dogs. They--the daylilies--can be beaten to the ground and still come back. Using different varieties you can have blooms from early June through the summer. For the fall: cushion mums.

To be avoided: grass. Use bricking or ground covers wherever you can, and hostas, which you can put right in the middle of the ground covers. Avoid ivy on buildings, wisteria, porcelain berry and any other vines that need a lot of pruning. (Clematis is okay.) Also to avoid: anything that has to be staked.

* Holly Shimizu, curator, National Herb Garden, U.S. National Arboretum-- Advises planting hardy perennial herbs such as Greek or Italian oregano, lemon balm, English lavender, germander. Easy annuals: basil and dill (plant them in a permanent place), coriander and fennel. Be cautious with mint and lemon balm as they're invasive.

Use raised beds; they're easy to weed and the area is determined. If you plant early in the spring so the plants get a head start, you won't have to water so much in hot weather.

Avoid herbs in pots unless you're committed to daily and twice-daily watering. Everything does better in the ground.

Keep ahead of the weeds.