IN THE GARDEN PITTOSPORUM A BOON TO EVERGREEN DREAMS.

Byline: JOSHUA SISKIN

Once upon a time, when people wanted carefree evergreen foliage plants that came in a variety of shapes and sizes, they chose junipers. <

They could choose from green, blue, silvery-blue and gold-tipped junipers. They could select not only from shrubby junipers galore, but also from junipers that were pyramids, spires or weeping trees, as well as from ground-hugging junipers and junipers that spilled gracefully out of terra cotta pots and bonsai dishes.

Junipers were wonderfully waterwise; once established in the garden, a good soaking every few weeks was all they would ever need to thrive.

But somehow, somewhere, someone decided that junipers were too harsh, too bristly, too scratchy for garden use. Besides, they did not produce flowers of any interest, so why not seek some softer alternatives?

Along came the euonymous bushes, the so-called spindle trees that were not trees at all but large-, medium- and dwarf-size shrubs. Their leaves were round, oval or elliptical and they were decked out in the most wonderful variegated combinations of either green and gold or green and silver. But for all their fanfare, they were hardly drought-tolerant, and most of them were stricken with powdery mildew fungus. These facts put a damper on well-laid plans for wall-to-wall euonymous-scapes, and the quest for a genus of all-purpose, yet diverse ornamental shrubs continued.

At long last, gardeners have slowly come to learn of a new group of variously sized shrubs and small trees that, once all of them are readily available, will provide the foliar relief long sought by the planting public.

The tar seeds, botanically known as Pittosporums (pitto = tar; sporum = seed), have arrived. Yes, some pittosporum types - such as Tobira and Tobira 'Variegata' - have been around for years, but the more delicate-leafed varieties and some of the dwarfs have only recently begun to make a contribution to garden design schemes.

There are more than 20 species and cultivars of Pittosporum (both pit- TOS-porum and pitto-SPOR-um are acceptable pronunciations) that would grow in Valley gardens. To date, I have seen less than half them in local nurseries, but others are sure to come.

The most exciting species of the genus is Pittosporum tenuifolium, dubbed kohuhu by the Maori people in its native New Zealand. I have seen the kohuhu variety 'Nigricans,' which has black twigs and purplish-bronze foliage, as well as the shimmering 'Silver Queen' with its tiny, round, gray-green leaves. But there are also the yellow and green variegated 'Abbotsbury Gold' and the gold-tinged 'Golden King' and 'Warnham Gold,' as well as the reddish-bronze dwarf 'Tom Thumb.' We can only wait expectantly for the appearance of these colorful shrubs in the near future, as all of them have mounding or compact growth habits and wavy, round or elliptical leaves.

In the meantime, it is possible to enjoy Pittosporum crassifolium 'Compacta,' or karo, a mounding shrub with soft gray-green foliage. Like the old standby and emerald green Pittosporum Tobira 'Wheeler's Dwarf,' karo contrasts well with red or bronze New Zealand flax (Phormium species) or any other shrub or perennial with vividly colored foliage.

Pittosporum eugenioides, the lemonwood, has pale green, wavy-margined leaves that exude a lemon scent when crushed. Lemonwood makes a fine hedge, growing up to 40 feet in height.

And lest we forget, there is no better background plant for a garden of partial shade than the creme-de-menthe-colored Pittosporum Tobira 'Variegata.'

TIP OF THE WEEK: If you are tired of sickly gardenias, ask your nursery to special order you a grafted plant from Monrovia Nursery. Correspondent Judy Lynes informs me that grafted gardenias perform much better than typical nursery plants, which are grown from cuttings. The root stock used for grafted plants is Gardenia Thunbergii, which develops deep green foliage with a minimum of fertilizer.

In the words of Monrovia's propagator Andrew Pound: ``Grafted gardenia plants outperform cutting propagated plants because the G. Thunbergii root system is resistant to nematodes, is tolerant of poor soil conditions, and is efficient at utilizing iron and other minerals from the soil.''