GARDENING : AUTUMN'S IMMINENT ARRIVAL THE TIME TO THINK ABOUT STARTING OVER.

Byline: Joshua Siskin

There is nothing like an empty canvas or a blank page to spark the imagination of a creative soul. George Bernard Shaw, the English playwright, was once asked which book he would bring to a desert island, if he could choose but one. ``A book of blank pages,'' Shaw replied.

Perhaps, then, this is the appropriate moment to ask the question: ``If I could plant a single garden, what kind of garden would it be?'' Although it might not be wise to actually put plants in the ground before October, when shorter, cooler days make it easier for plants to establish themselves, now is the time to sketch out a design and, more important still, prepare the soil for your new garden.

There are six basic, ornamental garden styles or concepts:

The formal garden, such as that exhibited at the original Getty Museum in Malibu, with neatly clipped, boxed hedges enclosing ``garden rooms.''

Informal, English or cottage garden, such as that found at the new Getty Center, which is a melange of mostly flowering plants, but also includes plants with distinctively shaped or colored leaves, sometimes called ``a gardener's garden'' on account of the constant maintenance required, especially in the areas of pruning, dividing and staking.

Tropical garden, with large-leafed plants such as banana trees, elephant ears (such as those growing around the waterfall just inside the entrance to the L.A. Zoo), split-leaf philodendrons, cannas and giant birds-of-paradise, as well as tropical fruit trees such as citrus, guava and papaya.

Southwestern or xeriscape garden, consisting of cactuses and succulents, ornamental grasses or leafy yet drought-tolerant plants, such as those encountered in California's chaparral (e.g. ceanothus and manzanita).

Woodland garden, where trees - or maybe a single large tree - such as sycamores or oaks predominate.

Japanese garden, consisting of a limited variety of plants that are intensively trained and pruned, their shapes representative of forms seen when viewing, from a distance, the surrounding natural landscape.