Rock gardening on the West Coast has come a long way. The early English rock garden was likely to be a scaled-down replica of some minute fraction of the Alps, which an English gentleman wished to reproduce in his garden.
Although the construction was sound and the plant material superb, the overall effect was not always satisfying because the setting was likely inappropriate.
However, rock gardening in Europe and America arrived at its present superior level when the suitability of surroundings began to receive more consideration.
The visitor to British Columbia, Washington, and Oregon is at once impressed by the masterly quality of the best of the northwest rock gardens, not the stoned-up banks of red rock cerastium, aubrieta, and alyssum that line the sidewalks but gardens where natural outcroppings of rock have been supplemented with boulders and planted with rifts of harmonious plants.
Since the climate of the Pacific Northwest suits alpine plants, available from excellent nurseries, and the coastal Rockland, Columbia River Gorge rock, and volcanic rock in the region supply plenty of foundation material, it is easy to see why rock gardening here has been so highly developed.
What To Plant In Rock Gardens
In California, there is no lack of natural sites for rock gardens, but there is the question of what to plant in them.
North of San Francisco, Northwestern rock plants will thrive to a certain extent, but what is there for the tufa sandstone and serpentine of San Luis Obispo County, for the gardener, on the hogback along Napa County’s Monticello Road, where every ridge sprouts lava?
And what for the rock gardener in rainless southern California, where most denizens of a northwestern rock garden would never survive their first summer?
Why not go out into the nearby countryside and examine some of nature’s samples, choosing those which best fit the setting provided by the home ground? There is a haunting charm to a hillside home rising out of natural unscarred surroundings.
You will never regret following the tips you get from nature, for she has been rock gardening since the beginning of time.
It is up to the gardener to supply discrimination, good taste, and originality, for few of us have enough space to operate on nature’s grand scale.
Near the foot of the Sierra Madre mountains in southern California, nature used the California poppy lavishly.
Miles of orange bloom glittering in the sun were, so we were told as children, and used as a landmark by vessels at sea.
This pervasive flower takes on a new character on the hill behind my present home in the face of a steep crag.
Its growth is lower and wider. The leaves are more sharply cut and silvery. It blooms larger and more intensely colored.
In May, the coastal swords below me are lilac with the massed bloom of Armeria maritima (vulgaris). Still, in the rock garden, a small colony of thrift takes on the fresh charm when it flowers above dwarf campanulas and lavender gathers.
Superior Variety For Southern Gardeners
There is a danger of overdoing the standard rock plants, which increases. Give your surplus to other gardeners.
For a change from uninspired rows of iris, pinks, and coralbells, try some of these accommodating plants – dwarf hypericums and campanulas, iberis, and Tunica saxifraga, nepeta, rock roses, alyssum, and sun roses – which will do almost anywhere.
Only the Northwesterner can hope to succeed with the ramadas and haberleas, which make such suitable companions for small, choice ferns.
With their low rosettes and lavender blue flowers, these plants should be given a moist niche in a shady grotto or tucked into a north-facing wall.
The exquisite fringed soldanelles, particularly S. montana and S. alpina, also need shade but should have a lower, flatter location where the soil is moist and rich with humus.
The Northwesterner can grow campanulas, dianthus, dwarf European heaths and heathers, and dwarf iris so well that using any but superior varieties seems a waste.
The southern gardener, who is denied such treasures as Campanula piperi, Anemone robinsoniana, and Ranunculus montanus, must fall back on the tougher rock garden plants.
If you live in the California Fog Belt, look for the well-made, well-stocked little rock garden tucked away in the greenhouse in Golden Gate Park.
If you want to duplicate this planting, you must give it the same good care bestowed by the nursery (prepared soil and plenty of water).
Tender Succulents
If you live in a frost-free spot, use tender succulents and the bright light green foliage and large crimson fruit of Fuchsia procumbens.
Remember the flowing lines of creeping rosemary and the architectural value of dwarf wild lilacs and manzanitas.
Full sun is always prescribed for rock gardens, but some of the most inviting on the Pacific Coast are to be found where foggy central California drops into the ocean.
Here, on a parcel of sandy soil or perched on the rim of a steep, rocky bluff, one can press into service some of the captivating native plants.
Why bore holes in your cliff and fill them with soil rich enough to support geraniums when there are so many alluring wildflowers that would be right at home?
If you go to Point Reyes, a little north of San Francisco, stroll along its rocky edge, and you will see one of the loveliest of fragrant wallflowers, Erysimum menziesii, with flat heads of creamy bloom encircled by dull green foliage. This 8-inch plant may be a foot or more across.
Notice, while you are there, the exceptionally good color forms of that huge lavender daisy, Erigeron glaucus, and the pink-flowered form of Arabis blepharophylla.
When driving along the coast road in Del Norte County in northern California, you will pass, a few miles south of Crescent City, an arresting stand of Sedum pruinosum, which smothers portions of the high bank on the left with small rosettes of blue-gray foliage.
This neat succulent, very like Cape Blanco sedum, so popular in the Northwest, makes an excellent rock plant in fog.
A Cactus Garden
A brave beginning in developing outstanding plant material for the dry rock garden in the Southwest has been made in the “cactus garden” (really a garden of succulents) at the Huntington Library in San Marino and the Aloe Garden in Balboa Park, San Diego. Ornateness should be supplied by the plants themselves and not by unusual rocks.
The brilliant reds and yellows of South African and Mexican plants will not look affected if the planting is kept simple and on the proper scale.
Magnificence can be toned down with gray foliage. Heat and drought bring out albescence: powder is thicker and whiter on leaf and stalk, hairs are longer, closer, and a paler silver, while coverings of down and wool become denser.
Where frost is not severe, Portulacaria afra, with reddish stems and small glossy leaves, provides a neat little bush, especially when pruned.
Kalanchoes add interesting foliage and flowers, and an assortment of mesembryanthemums will give radiance over many months.
Greenovia auria’s rosettes, closed during the hottest, driest months, are spread to receive the welcome rain.
In early spring come the sprays of flat, circular bloom, which remind one of yellow starfish. Greenovia is one of the most prepossessing of rosette-making smugglers, never invasive but thoroughly filling every crevice along its slow route.
Othonna crassifolia, a South African creeper often used as a pot plant, makes an agreeable mat for the temperate rock garden. Its small light green leaves are like tiny sausages; for months, its surface is started with dainty yellow daisies.
It is a mistake, however, to think that all succulents are at their best in the south, for many are better suited to cool, foggy summers and the northern rock garden where they get rain the year round.
It is also a mistake to think that the rock garden of the Southwest needs to be stocked entirely with succulents, for there are many other delightful flowers that give good results with better soil and more water than that required by succulents.
Lotus mascaensis is a shrubby legume from Tenerife with small, very narrow leaves of silver and yellow flowers.
It brings a feathery lightness to the stodgy effect that succulents will likely give and happily perpetuates itself by volunteers.
Low Annual Fillers
There are also the low annual fillers that sow themselves and provide color over a long period, such as the kingfisher daisy, Felicia bergeriana, and the fringed pink, Gilia diantltoides.
Even rose moss, Portulaca grandiflora, from Brazil, can be a joy if you rogue out unwanted colors. A 6-inch South African plant, the kingfisher daisy is a lovely shade of blue.
The fringed pink, one of California’s favorite wildflowers, grows from 3 to 6 inches tall, depending on the poorness or richness of the soil.
It is a pale pink with a yellow throat washed and spotted with purple. A fragile, phlox-like beauty, it sheets sandy, undisturbed fields in the south and grows beside railroad tracks everywhere.
With such a wealth of natural jewels to choose from, West Coast rock gardeners can stock their gardens with little trouble or expense and be assured of long-lasting radiance year-round.
44659 by Lester Rowntree