Morning glory Convolvulus sebatius var. Compacta (Photo: Joshua Siskin)
Repeated droughts over the past few decades have almost wiped out grass in Southern California.
Some old grasses are still green and don't need a lot of water to stay that way, so maybe we should say new grasses. These are often hybrid grasses that started out as tall fescue (usually the Marathon brand) but were replaced over time by perennial grasses such as Bermuda grass or Kikuyu grass. The former has thin leaves, while the latter has broad leaves similar to St. Augustine grass. Both have underground rhizomes and stolons (runners) on the surface, so they can tolerate drought, and Kikuyu stolons are thicker than Bermuda grass stolons. One of the most common uses of Kikuyu is on golf course fairways because of its toughness.
If you live near a park and see grass growing, it likely contains kikuyu grass and its rope-like stolons. The stolons will root wherever the nodes (the points on the stolon where the leaves grow) touch the ground. Collecting clippings from your kikuyu lawn will provide you with stolon fragments to grow a drought-tolerant lawn, so ask whoever mows your kikuyu lawn to give you some clippings. Bring the clippings back to your yard and plant them horizontally, taking care to ensure that the stolon stem fragments are buried below the soil surface while the leaves are exposed. Water the clippings generously until they begin to root, at which point you can gradually reduce the frequency of irrigation. Once established, kikuyu grass does not need irrigation more than twice a week to look good, and can survive with irrigation much less frequently than that. Kikuyu grass can also be grown from seed. Seeds are available from Stover Seed (stoverseed.com).
The downside to Kikuyu, like all tropical and warm season turfgrasses, is that it goes dormant during the colder months but remains green during mild winters. However, this dormancy provides an opportunity for vertical mowing, which breaks up the layer of thatch that Kikuyu has formed. This removes the thick, spongy thatch, making Kikuyu grass easier to walk on when it regrows.
The Kikuyu are the largest ethnic group in Kenya, whose seeds and stolons were collected from their ancestral lands in 1911 and eventually spread to tropical and subtropical regions around the world. Kikuyu was first brought to Pacific Palisades in 1918 to be used to prevent erosion in drainage ditches. From there, it spread throughout Southern California by wind-borne seeds. In flower beds, it is a troublesome weed, due to its deep rhizomes and vigorous stolons. Yet, its hardiness makes it by far the best lawn choice, given the ever-present threat of drought.
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As an alternative to lawns, gardeners often turn to ground covers, especially those that require little watering once planted. What makes these ground covers unique is, first and foremost, that their leaves spread out like a blanket. Their small, dense leaves prevent water from escaping from the soil. Topping the list of such ground covers is Drosanthemum floribundum, which forms a thick mat of 1-inch fleshy leaves. In late winter and early spring, its flowers (pink or lilac-purple, depending on the variety) are so dense that the leaves are hidden from view. When the leaves are visible, they are covered with what look like ice crystals. This is because the sun is hitting the tiny epidermal projections called papillae.
Climbing rosemary (Rosmarinus officinalis prostratus) is another ground cover that requires very little water to maintain. Its small leaves seal the ground, so no moisture can escape from the surface. It is worth noting that all rosemary species are very drought tolerant and do not require watering more than once or twice a month, no matter how hot it gets. Lantana is another ground cover in this category. We recommend the yellow, orange, orange-red, or confetti (yellow, orange, pink) shrub varieties of lantana. These can be kept to a height of about 6 inches with regular pruning. Climbing, more classic ground cover lantana cultivars include popular lavender-pink and white varieties, but their lifespan is not as long as their taller cousins.
Two less common ground covers do well in partial shade to full sun, have dense foliage and don't require watering: Asian jasmine (Trachelosperumum asiaticum) and dwarf periwinkle (Vinca minor). Both have clumps of dark green, 1-inch-long, diamond-shaped leaves that give them an elegance that other ground covers lack.
My motivation for writing about ground covers came from an email I received from Matthew Hunt, a San Clemente gardener who has been growing morning glory (Convolvulus sabatius/mauritanicus var. Compacta) in full sun to partial shade for eight years. For years, I have marveled at the flower power of this ground cover, with its profusion of gramophone-shaped, lavender-blue flowers that bloom throughout the summer and fall.
Coral spring Russellia equisetiformis (Photo by Joshua Siskin)
California Native Plant of the Week: The Morning Glories (Convolvulus simulans) are small, pink or blue, five-petaled flowers. Like many species of morning glory, this plant is an annual that climbs up surrounding plants to get more sunlight. It is found throughout Southern California and often grows in clay soils, which is unusual for California native plants. Many California native plants thrive only in well-drained soils. The genus name comes from the Latin convolvere, meaning “to twine around.”
Please send any questions or comments to joshua@perfectplants.com.
