HELLO YELLOW, IT'S GOOD TO HAVE YOU BACK.

Byline: JOSHUA SISKIN

SO MANY of the late-winter and early-spring blooming plants native to dry climates, like our own, have yellow flowers.

One of the most captivating plants presently in bloom is the sea dahlia (Coreopsis maritima), a California native with yellow daisy flowers. The sea dahlia demands a fast-draining sandy soil, the kind found in select areas of the Valley from North Hollywood to Woodland Hills.

If you have sandy soil, you will definitely want to plant the sea dahlia. Its finely lobed leaves and evergreen stems are succulent, so it requires a minimum of irrigation. Best of all, sea dahlia sows and naturalizes in sandy garden beds over a few years. It grows 1 to 3 feet high and possesses an indefatigable tuberous root system.

Many species of coreopsis bloom this time of year but perhaps none is more charming than the lacy leafed perennial ground cover, Coreopsis verticillata. It is an appropriate choice for cascading over and down retaining walls, hanging baskets and terra cotta pots. The ``Moonbeam'' variety has glowing sulfur yellow flowers.

Acacia trees, native to Australia and East Africa, put forth golden yellow flower puffs at this time each year. Acacias grow quickly in compacted soil and require little water; at maturity, they are no more than 25 or 30 feet tall. A good example is Acacia baileyana, the golden mimosa. Its blue-gray feathery leaves impart an unparalleled softness to the tree's canopy. Acacia baileyana purpurea, a variety with violet-tinted foliage, is also worth a second look.

The knife acacia (Acacia cultriformis) has fascinating triangle-shaped leaves, and the Sydney golden wattle (Acacia longiflora) produces scads of flowers in pendant, butter-yellow chains. Acacia redolens is a shrub so tolerant of drought and smog that it is used by Cal-Trans in highway median strips throughout Southern California.

No discussion of yellow flowers would be complete without mention of marigolds.

The low-growing Nugget or French marigolds, as well as the medium-size Inca and tallest Lady or African marigolds, do best when planted either before or after our long spell of hot weather.

Ironically, marigolds are most readily available in nurseries in summer, which is the worst time to plant them; they are prone to wilt when planted in hot weather. If you plant marigolds in March or in October, you should be rewarded with at least four months of blooms.

To increase flowering, snip off individual marigold flower heads as soon as they begin to fade.

Incidentally, the same planting times - March and October - are ideal for petunias, those South American gramophone-shaped flowers that are also just beginning to appear in nurseries. If you delay planting petunias until really hot weather - which typically asserts itself in April - you will have a much harder time making petunias feel at home in your garden. Planted now, petunias can easily last for six months in the garden, especially if they are pinched back just before they start to become leggy.

TIP OF THE WEEK: When planting roses, allow for a minimum of 3 feet between them. With narrower spacing, pruning becomes more difficult and plants will also grow into each other before you know it, causing the individuality of each to be lost among its neighbors.