Lovely, lush and low-down
Ground cover is one of those terms that one suspects would sound so much better in French. Couvert de la terre. The sheer bluntness of the American name only reinforces the lowly status of the class of plants -- below trees, below shrubs, below borders, below even lawn.
But sometimes the most impressive plants in the garden are beneath our gaze, tucked along a path, running under a tree. Ground covers not only are appearing in ever more tantalizing variety, they also are useful in every garden. They keep down dirt, control weeds and hold earth in place. Choose the right one and it can serve as visual glue and provide color, texture, variety, beneficial insects, scent and even cut flowers. Select the wrong one and you can become embroiled in a battle to either keep it alive or contain it.
The No. 1 American ground cover, of course, is lawn. But pity the parvenu who calls it ground cover. Centuries ago, landscapers managed to transcend the term by concertedly mimicking the manicured estates of England. The rituals of lawn care now so define American gardening that one of the warmest recommendations a nurseryman will give a ground cover is “You can mow it.”
With mowability a virtue by proxy, one of the most popular ground covers in Southern Californian nurseries is the South African import Dymondia margaretae. This silvery plant grows in a bed of tightly woven roots and leaves, similar to lawn except glittery. In the summer, it produces yellow flowers, which skulk so low that most would escape a high-set mower blade.
A bed of Dymondia is a strong and beautiful thing to behold. It’s not so fast-growing that it takes over. But you wouldn’t want to lie down in it either. It could get scratchy. Dymondia comes into its own as transition planting on parkways, creating segues from grass to gravel. In this context, it’s the height of conservationist chic.
You can mow oregano too, says V.J. Billings. Twenty years ago, she founded Mountain Valley Growers, a Fresno herb farm that has made considerable inroads selling herbs as landscaping plants by mail order. It sells half a dozen creeping, crawling and mounding oreganos suitable for ground cover and no fewer than 18 ornamental thymes. In fact, there are more varieties of thyme suitable for ground cover on her plant list than ones for cooking, including elfin, creeping red, woolly, coconut, caraway, pink chintz, lavender and white moss thymes.
Groupings of herbs make beautiful beds, but it’s hard to call them ground cover rather than bedding plants. They do meet the definition when they are planted along pathways and steps, and when they tumble elegantly here and there. The best are scented and bruise fragrantly underfoot.
For Billings, the truest characteristic of a ground cover is the ability to spread. Creeping capability can be assessed at a glance, she says. Look for leggy shows of stem. A vigorous creeper will need to flop, touching its stem to the ground, where it can send down new roots. The more vigorous a creeper, the more space it will have between its leaves, so the foliage doesn’t get in the way of the flopping, grounding and rooting.
As a working rule, the closer set the leaves, the slower a plant will creep; the farther apart, the faster.
Understand this and all sorts of things start to become clear, such as why two of California’s best-known ground covers, Wandering Jew (Tradescantia albiflora and Tradescantia fluminensis) and Periwinkle (Vinca), are famous across the rest of the country as trailing plants for hanging baskets. They’re trying to reach the floor.
The more vigorous a creeper, the harder the job we give it. If you have a nonirrigated hillside, gazanias and Osteospermum may be your plants. Both trailers do so much to stabilize soil climbing from highway verges that they are more commonly known as “freeway daisies.” But from the car, it’s hard to appreciate that these South African imports are quietly wondrous for another reason. Gazanias withstand a constant diet of heat, grit, smog and noise but still gracefully, almost prayerfully, open their flowers every day at dawn and shut them at dusk.
A lesser-known and simply gorgeous creeper is the Uruguayan import Dicliptera suberecta. The name guarantees a snigger, but the plant induces only quiet appreciation. For most of the year, it provides a foot-high stand of soft, largely pest-free velvety gray-green foliage. As it grows, the weight of the branches forces the limbs to the ground, where they put out new roots. Every June, it produces a rich head of tubular orange blossoms and is soon staked out by clicking hummingbirds. It’s forgiving of trampling, tolerant of shade and reasonably drought-resistant. It can be found at specialist plant sales and Roger’s Gardens in Newport Beach.
For a beautiful plant, it’s a hard sell. “You don’t see it very often,” says Roger’s Gardens nursery manager Ron Vanderhoff. The plant needs room to bloom. “If customers don’t see a flower, they walk right past it,” he says. The price, $8.99 for one gallon, is a better value than it might first appear. It roots so efficiently on its own and from cuttings that you’ll have a hillside of it in a year.
The toughest but most stunning creepers must be the succulents, usually lumped together as “iceplants.” Their sculptural, cool leaves produce flowers so wacky they seem fake, as if they’ve been plucked out of drinks at Trader Vic’s.
Over-watering is so bad for them that they are best planted out of reach of irrigation. When they get too dusty, shower them with a hose. They deserve it. They make superb, fire-resistant erosion control, but you will still need to choose small-leafed varieties or create wash channels so sudden rains won’t waterlog them. As the Sunset Western Garden Book aptly warns, the heaviest-leafed ones can become heavy and, on steep inclines, prone to slides.
We are attracted to specific ground cover by a plant’s beauty. But selecting any specimen for mass planting forces us to think about how the plant works and what conditions it needs. If it looks too delicate for L.A.’s climate, it probably is. The markets are full of wussy, temperamental imports. Soleirolia soleirollii, or baby’s tears, is sold as a native of somewhere in the Mediterranean. This could lead you to assume that it is drought-tolerant. But from the lushness of the soft, green leaves, it’s a safe bet that that somewhere in the Med was behind a waterfall. Be realistic where you put it. If you have a patch around a fountain splash-back that needs greening up, this is your plant.
Even native plants can be all wrong. One of the funnier observations in the Southern California Horticultural Society’s book, Selected Plants for Southern California Gardens, is how a native yarrow used as a lawn substitute in L.A. took more water than St. Augustine grass. It is, it emerges, a meadow plant.
In a logical world, we would plant not just with natives, but also in a geographically correct manner. But Robert Sussman, owner of Matilija Nursery in Moorpark, says that even proprietors of golf courses are coming around to gardening with the climate. Where they don’t need grass, they are increasingly using natives, which bring the best wildlife out of the woodwork: bees, ladybirds and butterflies. To Sussman, ground cover doesn’t have to creep. It can merely be a plant with a lateral tendency. He recommends prostrate California lilac, or Ceanothus, dark green shrubs with spangles of bright blue flowers. Varieties that can cover up to 6 square feet include ‘Yankee Point,’ ‘Emily Brown’ and ‘Carmel Creeper.’
But for a native creeper that really creeps, his choice is the California aster, or Lessingia filaginifolia, or ‘Silver Carpet.’ It has gorgeous gray- green foliage; it can clump; it can crawl; and it produces dandy little pink flowers. Add to that, says Sussman, it does the final, most important thing that we expect from ground cover. “It looks pretty nice year round.”
Emily Green can be reached at emily.green@latimes.com.
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Taking cover
Three independent nurseries with good selections of ground cover -- from conventional to herbaceous to native species:
Roger’s Gardens, 2301 San Joaquin Hills Road, Corona del Mar. (949) 721-2100. Open Sundays through Thursdays, 9 a.m. to 6 p.m.; Fridays and Saturdays, 9 a.m. to 7 p.m. Variety of ground cover including Dymondia, chamomile, baby’s tears, campanula. Trays with 50 plants, typically $16.99.
Mountain Valley Growers, 38325 Pepperweed Road, Squaw Valley. (559) 338-2775; www .mountainvalleygrowers.com/index.html. Flats of 128 tiny herb plugs, $46.80. Boxing and shipping, $12 for two flats. Internet and mail-order only.
Matilija Nursery, 8225 Waters Road, Moorpark. (805) 523-8604; www.matilijanursery.com. Open Mondays through Thursdays, 8:30 a.m. to noon; Fridays and Saturdays, 8:30 a.m. to 2 p.m. One-gallon plants, typically $5; 5-gallon, $15; specialty plants, $2 more.
