SO NICE, WE DO IT TWICE GARDENERS ENJOY A SECOND GROWING SEASON AS TEMPERATURES DROP.

Byline: Elizabeth Smilor Correspondent

Fall in Southern California is a second spring for gardeners. While gardens in colder climates are now put to bed for winter, another planting season is beginning here.

``The temperature is moderate, the soil is warm, and plants have the chance to get their root systems established before dormancy and then get off with a bang when spring rolls around,'' says Chris Greenwood, chief rosarian for Armstrong Garden Centers.

October is the peak time to plant everything from shrubs to perennials to bulbs - if the temperature drops.

``You have to keep in mind that it can still be hot and dry, particularly in the Valley with the Santa Ana winds,'' cautions Kathy Post, an associate at Sperling Nursery in Calabasas.

Conditions permitting, though, garden experts agree fall is the perfect time to refresh and renew your yard.

Maintain and refresh

Before any renewal can begin, lawns and flower beds will need a little help recovering from the hot sun.

Fescue or cool-season lawns, which stay green all year, will begin an active growing phase in October, says Post. She advises applying an all-season fertilizer with at least 15 percent nitrogen now. Then set your mower to cut shorter and taper back watering as the weather cools. She recommends watering deeply for 20 to 30 minutes - but only twice a week once the hot and dry conditions pass.

St. Augustine or Bermuda lawns, on the other hand, are warm-season lawns that will grow slower in October and November before going dormant. To keep them appearing green until March or April, apply an annual rye seed in October, Post says.

If your flower beds are looking a little sad, start by cleaning them up. Remove diseased branches and twigs, advises a checklist from Green Thumb Nursery in Canoga Park. It also recommends raking up leaves from under trees and old flower blossoms out from under camellias.

If your roses are looking a bit stressed out from the heat, do a light pruning now to remove any dead blooms, branches and leaves, says Post. Do not fully prune your roses until January.

``Look out for rust and aphids, remove old flowers, feed them one or two more times, and you'll have flowers until Christmas,'' says rosarian Greenwood.

Any 2- to 3-year-old clumping plants, such as daylilies, irises, Shasta daisies and agapanthus, may be divided in the fall. Better Homes and Gardens' ``Step-by-Step Garden Basics'' book shows how to divide plants by digging up the clump, spraying the soil off the root ball and then separating the individual plant crowns with a sharp knife. You can replant the divisions elsewhere in your garden or discard them. This process will control the size of your plant and promote new blooms in spring.

Another plant that needs special attention now is hydrangea. To keep blue hydrangeas blue, the soil around them must be treated with aluminum sulfate. Pat Welsh's ``Southern California Gardening'' advises using 1 tablespoon of aluminum sulfate per foot of plant height mixed with water and applied several times in fall.

Once beds are clean and flowers refreshed, apply an all-purpose fertilizer and cover the ground with a fine-grind mulch or compost to keep it moist and healthy, Post advises.

Finally, if you live in an area prone to high winds, thin out big trees - such as ash or elm varieties. An experienced arborist can help reduce the size of the canopy to prevent limbs from breaking in winds, says Post.

Renew your space

With your yard cleaned up, it's easy to see where you'd like to add something new. And as Green Thumb's checklist points out, fall is planting time. Everything from a new lawn to trees, shrubs, bulbs and perennials can be put in the ground now and be well-established by spring.

This is the best time of year to install a cool-season lawn from either sod or seed, the experts agree. It's also the time to add permanent garden features such as trees, shrub hedges and vines.

``This is the finest time of the year to put in garden staples that last for years and become the backbone of the landscape,'' writes Welsh in her ``Southern California Gardening'' book.

Welsh recommends planting all but tropical varieties in October. (Tropicals should be planted in spring.) Some tree options are Chinese Elm, Australian and New Zealand tea trees, and melaleucas. Popular shrubs are India hawthorn, lavender starflower and yew pine. Vines include Cape honeysuckle, lilac vine and ivy.

Now add some color to your garden. Plant mums, pansies, violas, alyssum, primroses, stock and snapdragons for instant color. Nurseries are stocking these blooms now. At Armstrong Garden Centers, with locations in Glendale, Sherman Oaks, Thousand Oaks and Valencia, new pansies from Italy called ``farmen'' come in bright colors with ruffled edges, Greenwood says.

All varieties of sweet peas should be planted soon. ``I follow my grandmother's adage to plant them with the first full moon in October,'' says Post. She recommends putting in a multiflora variety such as ``Winter Elegance'' or ``Early Mammoth'' for flowers by the winter holidays.

She also recommends planting California natives, such as California lilacs (Ceanothus) and Matilija poppy, in October and November.

When most of us think of fall gardening, we think bulbs. Some spring- blooming bulbs may be planted now. These include South African bulbs such as freesia and watsonia as well as bearded and Dutch iris, says Post. Anemones, daffodils and ranunculus are ready for planting in October and November. Other bulbs - such as tulips, hyacinth and crocus - you'll want to buy now to chill for six to eight weeks.

``Place them in the refrigerator in the crisper, not the freezer, and plant them in December and January,'' advises Post.

Green Thumb advises using a generous amount of bone meal when planting bulbs. Place some at the bottom of the hole and cover with dirt so the bulb doesn't touch the bone meal.

Finally, if you have or want a vegetable garden, there are plenty of cool-season varieties to plant. Lettuce, cabbage, beets, turnips, radishes, broccoli, cauliflower and carrots may be planted from seed or transplanted now. Greenwood says Armstrong centers also have a new tomato plant developed in Siberia that produces crops in fall and winter.

So, when the air outside feels cool, put on your gardening gloves and welcome our second spring.

Fall checklist

--Fertilize cool-season lawns.

--Add rye seed to warm-season lawns.

--Clean up flower beds.

--Feed roses and other blooms.

--Divide clumping plants.

--Mulch flower beds.

--Install cool-season lawn.

--Plant trees, shrubs and vines.

--Plant fall annuals and perennials for color.

--Plant bulbs.

--Plant winter vegetables.

- E.S.

CAPTION(S):

8 photos, box

Photo:

(1 -- cover -- color) Cosmos

(2 -- color) Japanese anemone 

(3 -- color) Pansies

(4 -- color) Zinnias

(5 -- color) Rubeckia Cherokee

(6 -- color) Bulbs

(7 -- color) Chrysanthemums

(8 -- color) no caption (garden tools)

Evan Yee/Staff Photographer

Box:

Fall checklist (see text)