The Easter lily can be planted outdoors in the garden when danger of frost is over, about three weeks from now. Take it out of the pot and plant it in a sunny place. It will die down but come up again in late summer and, maybe, bloom.Give it a heavy mulch during the winter and it may continue to bloom for years. Don't try to force it into bloom again for nest Easter - odds are against it.

One of the best things you can do for your tulips when they finish blooming is to pinch off the faded flowers. If left on, food (energy) would be spent producing seed; otherwise, that energy would be stored in the bulbs for better flowers next year. Don't pinch off the stems and leaves, just the faded flowers.

Tulips and hyacinths usually produce their best flowers the first year they're planted. Daffodils and crocuses should be better the second year and even more so the third, because they multiply and there are more flowers.

The foliage of all spring bulbs should be encouraged to stay green as long as possible. The foliage produces the food (photosynthesis) to be stored, and the more food, the larger the bulbs and the better the flowers.

Don't tie up the tulip foliage with rubber bands. If you do, it can't produce as much food because less leaf surface is exposed to sunlight. Wait until the leaves begin to droop and shrivel before cutting them off.

Keep weeds out of the tulip bed; they compete for moisture and nutrients. Water the tulips during dry weather.

Many gardeners dig their tulip bulbs every two or three years and separate them. In naturalized plantings, especially if the bulbs are planted deeply, they can be left for many years. If soil conditions are good and they get fair treatment, they should continue to bloom for years, but the flowers will be somewhat smaller each year.

Tulip bulbs that are dug should be cured before being stored. Lift them carefully after the foliage turns yellow, remove the tops and wash soil from the bulbs with the hose. Spread them out in a shady, airy place to dry thoroughly. This takes about a week or 10 days. Then put them in shallow boxes and store in a cool, dry place.

Your best bet with hyacinths is to leave them in the ground. They will bloom year after year with smaller flowers each year. When they no longer please you, dig them up and discard them.

Daffodils multiply, and when they get crowded they need to be dug and separated. Otherwise, many varieties stop blooming. Some kinds can go on for years without being separated, but most require it every four or five years.

Your best bet with daffodils is to replant the bulbs immediately after separating them. If the bulbs are stored at temperatures much above 65 degrees they may lose some of their quality, and the best place for them is in the ground.

ARBOR DAY IN ANNAPOLIS

Wednesday is national Arbor Day, and the Maryland Arborist Association will be giving the expert care to trees in the yard of the Governor's House in Annapolis, starting at 9 o'clock. If you want to see what goes into the care and pruning of a horse chestnut, a sugar maple, a red maple and a linden, that's the time and place to do it. For more information contact Barbara Newman at 301/269-2235.

A NORTHERN NECK HOUSE TOUR

Wednesday is also the day that the Garden Club of the Northern Neck of Virginia is observing Historic Garden Week with a home tour that includes, among other things, the house John Dos Passos lived in until his death in 1970 (with some of his paintings on display). That house, like most of the places on the tour, was built in the early 1800s, but the tour also includes the Yeocomico Church, built in 1706. Block tickets are $7, single admission $2. For advance information call Mrs. Benjamin B. Morris at 804/493-8307 or Mrs. Lloyd T. Griffith at 804/472-3145.