Gardening : Gardener Challenges Tough Soil, Succeeds : Plants: Despite gummy adobe soil and unfavorable sunlight conditions, exotic plants now thrive.
If you think you have a tough row to hoe, imagine how Cathy Ratner felt 11 years ago as she started work on her new garden.
The soil was stiff, black adobe--gummy when wet and hard as a brick when dry--over a layer of chalky, highly alkaline diatomaceous earth. To make matters worse, the north-facing hillside portion of the garden gets no direct sunlight most of the winter but hot sun in summer.
Clearly, she had some experimenting to do to find the right plants for these daunting conditions.
First, she divided the garden in two. The level and gently-sloping areas surrounding the house became a border of perennial plants that is watered weekly in the dry season, while the north-facing hillside gets by on rainfall alone.
(At least it did until this year when drought forced Ratner to water the hillside once a month January through April.) The soil of the perennial border was improved with compost but the hillside adobe was left unamended.
With these cultural conditions set, the garden became a mosaic of ecological niches in combinations of wet, dry, sunny, shady, poorly-drained and slightly better-drained. When Ratner wanted to try a new plant, she bought at least two or three of the same species and planted them in differing situations.
Over the years of nonstop nurturing, Ratner, a nursery-school teacher, has built not only a beautiful garden but also an impressive knowledge of the needs of a wide array of rare and seldom-cultivated plants.
The Ratner garden is in Palos Verdes Estates where foggy mornings and cool ocean breezes are the rule much of the year. Experimenting with native plants for the dry hillside, she found that shrubs from the canyons of the coast ranges and the Sierra such as red flowering currant (Ribes sanguineum) and California mock-orange (Philadelphus lewisii) outperformed species from hot, gravelly chaparral slopes.
Mountain-lilac hybrids descended from coastal species such as Ceanothus ‘Ray Hartman’ and ‘Julia Phelps’ perform brilliantly, but many natives, resenting the alkaline heavy soil and lack of winter sun, refused to grow.
Casting about for plants that would accept such trying conditions, Ratner became a connoisseur of rare plants found only on the islands of the Mediterranean and the coast of north Africa--Corsica, Crete, Madeira and the Canary Islands. Sampling their rich floras, she found plants adapted to her cool, dry coastal climate and alkaline soil.
One success on the dry hillside has been Geranium maderense. True geraniums grown in California (as opposed to the familiar pelargoniums commonly called “geraniums”) are mostly low, mounding plants, but this species from the island of Madeira grows to 4 feet tall, 3 feet wide, and has leaves as much as 2 feet across. Its tall stalks of purplish-pink flowers are densely covered with glistening purple hairs.
Salvia canariensis , a six-foot tall sage from the Canary Islands with lavender flowers surrounded by wine-red bracts, must feel right at home in the Ratner garden, accompanied by the Canary Island lavenders, euphorbias and echiums that grow with it in the wild.
It also grows well in the UC Riverside Botanic Garden, so don’t think you have to live in the fog belt to try some of these island species.
Another striking Canary Islands perennial (Isoplexis canariensis) is a tall, orange-flowerd relative of the foxglove. Native to the moist woods of higher elevations, it failed on Ratner’s dry hill but is thriving in the watered border along with a pair of perennials from the isle of Corsica--a brilliant blue-flowered, low-growing borage (Borago laxiflora) and green-flowered Corsican hellebore (Helleborus lividus corsicus) , grown mostly for its extremely handsome blue-green leaves.
The hellebore, often recommended for dark, dry shade, proves its reputation by thriving under Ratner’s deck where it produces hundreds of volunteer seedlings.
In the spring, wild tulips from Crete (Tulipa saxatilis ) produce wide-open lavender flowers with yellow centers. They multiply steadily in Ratner’s garden, while another mild-climate species, the lady tulip (T. clusiana) , merely survives.
What appears to be a clump of giant onions bursting out of the dry adobe are sea squills (Urginea maritima) . The progeny of a single bulb Ratner collected on Crete, they are dormant now but will shoot up dramatic five-foot tall spikes of white flowers in late summer. ( Urginea bulbs are available at the L.A. Arboretum gift shop, telephone (818) 446-8251).
For cool-season annuals, the dry hill has native wildflowers, including clarkias and Chinese houses mingled with Mediterraneans such as Shirley poppies, love-in-a-mist, Queen Anne’s lace, Echium ‘Blue Bedder’ and corn-cockle ( Agrostemma ‘Milas’).
The remarkable success of Cathy Ratner’s garden is not merely that she was able to grow so many unusual plants, but also that she was able to get them in the first place.
Ask where she got a particular plant and the answer is likely to involve one or several of the following sources: the Royal Horticultural Society’s seed list, specialty nurseries all along the Pacific coast, eastern mail-order houses, commercial seed catalogues, botanic garden sales, a network of gardening friends, and, naturally, her mother’s garden. It shows what can be done with knowledge, persistence and some good hard clay.
