IN THE GARDEN SYCAMORES BEAUTIFY VALLEY STREETS.

Byline: JOSHUA SISKIN

If the distinguishing characteristic of beauty is simplicity, it is easy to understand why Cantura Street in Studio City and stretches of Teesdale, Beeman and Babcock avenues in North Hollywood are the most beautiful byways in the Valley.

On all of these streets, the canopies of California sycamores form an archway overhead. Planted in the parkways on both sides of the street, these sycamores lean lovingly toward each other and touch. In the City of Angels, it all reminds you of those cherubs, described in the book of Exodus, that adorned the ark of the covenant. Like these sycamores, the cherubs faced one another and made contact with their wings, which were lifted up above their heads.

When you realize that the California sycamore is a Valley native, you wonder why the parkways of only a handful of streets have been graced with its presence. Drive down almost any Valley street and you are witness to a hodgepodge of arboreal confusion.

On my own street, for example, you will find the following collection of parkway trees: jacaranda, carob, eucalyptus, crepe myrtle, carrotwood and Canary Island palm. The trees may be individually impressive, but together they create nothing special. Where parkway trees are leafy and uniform up and down the block, a warm and welcoming atmosphere combines with a feeling of elegant opulence.

Before there were streets in the San Fernando Valley, California sycamore (Platanus racemosa), valley oak (Quercus lobata) and coast live oak (Quercus agrifolia) dominated the landscape. It would have seemed simple and logical to utilize these indigenous species as parkway trees.

One of the advantages of planting sycamores and oaks is their longevity. These trees have strong immune systems and heal quickly when branches break or diseases take their toll. On the other hand, common street trees such as crepe myrtle and evergreen pear have weak immune systems and are not long-lived.

Not only are Valley parkway treescapes unremarkable; distinguished front-yard plantings are also rare. Most of the time, all you see is a square of lawn with some shrubs along the front of the house and perhaps down the driveway. If there is a garden of any interest, it is usually in the back.

Memorable front-yard plantings combine the virtues of no more than two or three plants, with foliage color or form playing a major role in the design scheme, while flowers are of secondary interest. For example, I once saw white bougainvillea vining up a south-facing fence with giant mounds of 'Sun Stripe' Pampas grass growing in front of it. The yellow- striped leaves and white plumes of the Pampas grass matched up well with the yellowish foliage and white bracts of the bougainvillea.

Another attractive planting featured ornamental bronze loquat trees underplanted with white carpet roses. In a similar vein, 'Bronze Beauty' (hybrid between loquat and Rhaphiolepis) shrubs contrast nicely with white Iceberg roses. These same Icebergs are seen interplanted with either violet-flowered and gray-leafed fragrant lavender (Lavandula species) or with violet-flowered and cabbage-leafed sea lavender (Limonium perezii).

The spearlike burgundy foliage of certain New Zealand flax (Phormium) varieties combines well with the shimmering green globes of dwarf mock orange (Pittosporum Tobira 'Wheeleri'), the blue fingers (Senecio mandraliscae) ground cover, or the yellow and green variegated 'Old Gold' spindle tree (Euonymous).

TIP OF THE WEEK: As a general horticultural rule, initial soil preparation for annuals and flowering perennials should include incorporation of compost at the rate of 8 cubic feet per 100 square feet of planting area.

There are many different compost products to choose from at the nursery, and any one of them will do the job. Then again, you can make compost yourself out of cut grass, fallen leaves, coffee grounds, tea bags, egg shells, and fruit and vegetable peels.

For fertilizer, it is best to use organic blends, such as ``Dr. Earth'' formulations. On a yearly basis, replenish previously amended annual beds with 2 to 3 cubic feet of amendment per 100 square feet, but you should apply the full amount of organic fertilizer each time you replant.