HOW GREEN IS OUR VALLEY CSUN BOTANIC GARDEN BRINGS BEAUTIFUL DIVERSITY TO TWO-ACRE SPACE ON CAMPUS.

Byline: Barbara De Witt Staff Writer

Summer garden parties provide a break before fall planting season and a chance to revel in spring's bounty.

In the case of California State University, Northridge, they also provide a chance to raise much-needed funds for the university's two-acre Botanic Garden and greenhouses.

The third annual Twilight Garden Party later this month will feature food, wine- and beer-tasting, music and an art show as well as informal garden talks by docents. Proceeds will be used to purchase and install plant identification signs and enhance the garden's overall appearance.

But visitors don't need to wait until the Aug. 23 event to learn more about CSUN's Botanic Garden, an eclectic mix of cactuses and succulents, perennials and exotics.

Created for the university's biology department more than 40 years ago, the garden also serves as a community resource for special events such as weddings and garden club meetings as well as a place to gather garden ideas.

``We've learned so much while pulling weeds and grooming the grounds because there are plants we've never heard of, much less realized they grow well in this area,'' says Rita Desilets of Van Nuys, newly elected president of the Southern California Garden Club and a member of Friends of the Garden, the volunteer group hosting the Twilight Garden Party.

Well-kept secret

Originally, the CSUN garden featured just an acre of grass and trees, says manager Brian Houck. Over the years, a second acre was added featuring a koi pond and five distinct planting areas: a cactus and succulent garden, a perennial garden, shady groupings, a New Zealand garden and greenhouses.

``We find people peeking over the wrought-iron gate every day, exclaiming they never knew this was here,'' Houck says.

In each garden, visitors will find uncommon plants that thrive in the Valley and surrounding region. In the New Zealand garden, gardeners can discover how to create a humid microclimate for tree ferns and New Zealand flax, noted for its green and burgundy leaves.

In the Asian garden, which is part of the shady area, there are orchids, Japanese maples and sago palms, which actually are not palm trees or ferns, says Houck's assistant Brenda Kanno, but an evergreen also known as a cycas.

The highlight is a 40-year-old ginkgo biloba, also known as a maidenhair tree, whose species dates to prehistoric times and serves as a starting point for students learning about tree biology, explains Houck. Female ginkgo biloba trees produce an odor caused by butyric acid that forms when the fruit rots. Some biologists surmise the smell prevents predators from eating the fruit's seed.

In the tropical greenhouse are bromeliads, which are in the pineapple family. The bromeliads have leaves in brilliant reds and purples, and the flowers come in red, pink, yellow, blue and green.

``The flowers are so bright that they look fake,'' says Kanno, who adds that they can be grown in containers on patios, in greenhouses and in the niches of trees by anchoring them with a nail or tying them into place and misting frequently.

Keith Peabody, a horticulturist at Sperling Nursery in Calabasas, says most of his customers keep them indoors and care for them like orchids. They're priced from $10 to $40, depending on the size.

In the perennial garden, visitors can find Texas rangers, a hearty evergreen shrub with gray foliage that blooms with magenta flowers. Although not as well-known as sages, they're available at local nurseries in the early fall.

August garden duties

While CSUN's garden provides a rich display for serious and casual visitors, its lush landscape also presents a challenge for Houck and his staff. Until the weather cools off - at least into the 80s - he and other experts outlined a variety of maintenance tasks local gardeners can perform to keep their own yards vibrant throughout the remaining summer.

``At this time of year, roses may be getting tall and spindly, so you may want to trim them back, but keep up with fertilizing and dead-heading and make sure the leaves are dry at night,'' advises Houck.

Desilets, who tends 180 rosebushes at her home, says watering roses at night is a real problem because the leaves are vulnerable to mildew. Her remedy is a mixture of one teaspoon each of baking soda, liquid dish soap and vegetable oil mixed in a spray bottle with a gallon of water. If the concoction is sprayed on the mildewed areas in the late afternoon, the problem should clear up within a couple of days, she says.

Iron chlorosis is another problem, Houck says. The iron deficiency disease affects plants such as camellias, gardenias and azaleas. Symptoms include yellowish leaves with green veins and gardenias that bloom then suddenly turn brown and drop their flowers. The problem can be fixed with iron supplements, sold in powder and granule form at nurseries.

Sprucing up existing plants is something all the experts recommend, beginning with geraniums, which can grow spindly looking, particularly the specially bred types with dainty lavender-colored or double flowers.

The best bet for beginners is the balcom variety of geraniums noted for pink flowers, says Sperling's Peabody. Sold in hanging baskets as well as flats for hillside ground cover, they are extremely hardy.

Regardless, he recommends feeding geraniums now for continuing blooms. Other plants, such as camellias and azaleas, can be given a slight trim to keep their shape after heavy blooming. But make sure the plant is healthy, otherwise pruning during intense heat could kill it, Houck cautions.

In fact, proper watering remains the biggest challenge for gardeners in August and early September.

Some gardeners water too often or too late in the evening and drown the plants, while others don't realize that potted plants may need daily watering during extreme heat.

To keep plants as moist and cool as possible, cover flower beds with mulch, whether it's ground bark, pine needles, weed-free straw or dried grass clippings. And consider the use of the new time-release moisture granules, Desilets suggests.

Also be vigilant about checking for irrigation problems. Look for water leaks, broken or clogged sprinkler heads and rotted hoses.

To further protect delicate flowers and prevent rose petals from getting sunburned, cover them during the midday heat with umbrellas or shade cloth, which is sold in rolls for about $30 at home improvement stores. Each piece will need to be held up with stakes.

Barbara De Witt, [phone]

barbara.dewitt(at)dailynews.com

THIRD ANNUAL TWILIGHT GARDEN PARTY

What: Jazz, art, wine and beer tastings with guided tours.

When: 5 to 9 p.m. Aug. 23.

Where: CSUN Botanic Garden, 18111 Nordhoff St., Northridge. Free parking in Lot G4 off Zelzah Avenue, just north of Prairie Street.

Tickets: $20 each; $35 per couple. Make reservations by calling [phone] by Wednesday.

Hot-weather tips

--Best time to water is 6 a.m. - and no later than 10 a.m.

--For spot color try marigolds, petunias, vincas and verbenas.

--Water roses frequently, but keep leaves dry at night.

--Spruce up geraniums by feeding, dead-heading and trimming back.

--Dig out cool-season crops and start amending soil.

--Fix any irrigation/sprinkler problems.

--Don't water succulents until leaves look shriveled. When plump, they're still holding water.

--Trim heavy tree branches now so they won't break in late-summer winds. Cut back spindly branches on shrubs and roses.

--Give potted patio plants a weekly feeding of liquid food and daily misting of water.

--Mow lawns and trim hedges in late afternoon to protect the plants as well as the gardener from heatstroke.

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9 photos, box

Photo:

(1 -- cover -- color) ON THE COVER: Bright orange flowers add to the exotic nature of the tropicanna plant found in CSUN's perennial garden. It's easy to grow in the Valley and currently available at most nurseries.

(2 -- 3 -- color) Brian Houck, manager of the CSUN Botanic Garden, is proud of the fern trees and other tropicals growing in the campus greenhouse, which will be open to the public on Aug. 23. At right are hybrid cactuses noted for their large, colorful blooms.

(4 -- color) Jerusalem sage is a good choice for Valley gardens - it flourishes in heat and requires little watering.

(5 -- color) One of the biggest surprises to CSUN garden visitors is this huge pond filled with koi, catfish and water lilies.

(6 -- 8 -- color) Among the plants you'll find at the university's garden are bromeliads, left and center, a plant that belongs to the pineapple family; and salvia, a popular type of sage noted for its blue flowers.

(9) CSUN Botanic Garden manager Brian Houck has created a separate garden with a New Zealand theme, featuring plants that can grow in the Valley when provided with shade and water.

John McCoy/Staff Photographer

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Hot-weather tips (see text)