GARDENING : SUN-LOVING, FLOWERY ROCKROSE GAINS CALIFORNIA FOOTHOLD.

Byline: Joshua Siskin

If there's one plant that behaves in every way like a California native, but isn't one, it's the rockrose.

For years, I assumed rockrose (Cistus spp.) was a native because I had seen it growing on rough embankments along freeways near Pasadena and Santa Clarita. The terrains were so steep and the soil appeared so poor that I could not imagine how any plant, excepting a native, could grow there.

To this day, I wonder how these plants got started. Did someone carry rockroses up these embankments riding on a mule, or could these be windblown volunteers, the results of seeds that just happened to find the right cracks in the soil for germination and growth?

The sun-loving rockroses resemble California natives in the following ways: They grow best on slopes, seldom (if ever) survive transplanting from one part of the garden to another, bloom in the spring, have fragrant, felt-textured leaves, are frequently short-lived, resent heavy pruning, and dislike summer irrigation.

Unlike California natives, they are relatively easy to propagate vegetatively: Once flowering has ended, take 3- to 6-inch shoot tip cuttings and stick them in small pots containing any well-drained soil mix; keep plants in light shade until roots begin to form, which should happen within six weeks, then move to a sunnier location.

Rockroses flower in all shades of pink and rose, and in white. The flowers have the texture of crepe and may often have beauty spots at the base of their petals.

Their sticky leaves are fragrant and contain an oil which is used to make incense in their Mediterranean countries of origin, especially Greece. The process is described in ``Flowers of the World,'' by Frances Perry: ``Collection is made by goats, which small boys round up and drive through the Cistus thickets. A gum sticks to the goats' hair, which, at the end of the operation, smells considerably sweeter than it did beforehand ... then the hair is cut, placed in vats with water and brought to the boil. The substance extracted is known as ladanum, which is also thought to be the fragrant myrrh of the Bible.''

Rockroses are broad shrubs, growing into specimens 3 to 5 feet tall whose girth may be twice the extent of their height. Suitable complements to the rockrose - both for their color and form - are the related sunroses (Helianthemum nummularium). Sunroses are low-growing plants not exceeding 1 foot in height that spread out like mats and bloom in red, pink, orange, yellow or white. Another relative worth looking for is Halimium lasianthum, which has yellow flowers and gray leaves.

Rockroses should be continually propagated as a hedge against their sudden demise, which should be expected at any time after their first year in the ground, although they may survive for up to five years after planting. No matter how tempting, avoid watering more than once or twice during the summer. As their name implies, they grow well in rock gardens with gritty, fast-draining soil.

Healthy eating: From gritty soil to gritty people ... comes the story of Pauline James, who has written a book called ``Your Good Health Garden'' (Woodbridge Press, 1995). How do you know that Pauline is a sincere person worth reading? Her publisher's press release includes Pauline's home phone number, and when you call that number, she picks up the phone herself!

In casual conversation, you soon learn that - assisted only by her husband - she grows enormous quantities of vegetables, harvesting 200 pounds of them per week, all of which are donated to homeless shelters and food banks in the Long Beach area where she lives.

Pauline teaches that certain vegetables ``require more energy to digest than they contain,'' creating ``deficit calories''; you can't help but lose weight, then, by growing and eating such plants. Examples of such vegetables and the deficit calories created per cup of consumption are: raw carrots - 45; cucumbers - 14; celery - 20; eggplant - 25; cabbage - 20; green beans - 45; cauliflower - 30.

Here are some of Pauline's helpful hints: ``Boiling water poured down an anthill will destroy the nest; a few flowers or flowering herbs planted among the vegetables helps attract insects that aid in pollination; if you add manure to the ground for root crops such as carrots, beets and turnips, the roots will split.''