Ornamental Grasses

In the wake of last week’s column, several readers have e-mailed testimonials that tout successful slope plantings.
Carol LaRoche of Chatsworth extolled Mexican feather grass (Stipa or Nassella tenuissima) as follows:
“It only needs water once or twice a week and it seeds itself all over my back slope. It turns from green to silver to gold as spring becomes summer and summer turns to fall. I do not need a water garden because when I look at my Mexican feather grass I see numerous illuminated fountains that quiver in the slightest breeze.”
Ornamental grasses, which are available in many colors, grow well on any slope with decent soil drainage.
Some grasses, such as pink muhly (Muhlenbergia capillaries) can also grow in heavy soil. Pink muhly, whose 6-foot-wide clumps reach a height of 3 feet, displays pink flower plumes that are nearly 3 feet tall themselves, in the fall.
If you are partial to blue, select from blue oat grass (Helictotrichon sempervirens), blue lyme grass (Elymus or Leymus arenarius) and common blue fescue (Festuca ovina glauca).
For well-irrigated slopes, you may prefer one of the variegated cultivars of Miscanthus sinensis, such as `Zebrinus,’ `Stardust’ or `Strictus,’ or one of the wistful sedge (Carex) species.
There are dozens of ornamental grasses from which to choose. You can get acquainted with them at www.bluestem.ca.
Arthur Davidson, who lives in Canyon Country, praised the red Flower Carpet rose for its durability on his slope.
“I have tried many different ground covers over the years, and none of them lasted. Finally, I thought I would give the Flower Carpet rose a chance and was delightfully surprised. It grows into a large shrub and just keeps flowering from spring to winter. Around the end of February, I cut my slope of roses almost to the ground only to see a wonderful rejuvenation as the weather warms.”
You could mix the different Flower Carpet rose varieties together for a multicolor affect as they are also available in pink, coral, apple blossom, yellow and white.
Cheryl Kaplow, a Studio City gardener, has turned her hillside into a blanket of reddish pink:
“Among bougainvillea varieties, I was always fondest of `James Walker,”’ she writes. “I had read about it growing on banks so I planted it to see what would happen. It does a nice job of covering the ground even if I had to cut back vertical growth, initially, so that it would spread more quickly in horizontal directions.”
A bonus of growing bougainvillea is that, once established, it does not require summer irrigation.
Alan Pollack, writing from Woodland Hills, recommends California native plants for slope stabilization. California redbud, California fuchsia, toyon and lemonade berry are noteworthy, he says, because of their deep roots.
Developing a taste for California natives requires a shift of focus since, unlike Flower Carpet roses or bougainvillea, you are not likely to see flowers for months on end. Due to their ecology, California natives bloom mostly in the winter and spring.
California fuchsia (Zauschneria californica or Epilobium canum) is distinctive among local natives, bursting into bloom just as the weather turns scorching hot.
It is a wispy ground cover with slender gray leaves and small, flared, orange to red tubular flowers. The steepest slopes do not deter it. As you drive up Coldwater Canyon from Ventura Boulevard to Mulholland Drive, you may see it blooming on the embankment to your right.
Firethorn (Pyracantha) is a plant you used to see a lot more of than you do today.
Nevertheless, it is still a worthy candidate for slope planting, especially on low-maintenance, precipitous, but adequately irrigated slopes where little else will grow. I refer, in particular, to the more than 10-foot-tall, rapidly growing, rangy firethorn species (Pyracantha coccinea).
It provides year-around interest with a snowfall of white blossoms in spring and loads of usually red, but sometimes orange, berries from late summer until early winter, as well as lush evergreen foliage.
Although it is a plant that does not get much attention due to its thorns and susceptibility to diseases, it is one of those shrubs that you can plant and forget about, if you choose, and just watch it take over. Its fruit is tasty to birds, which assist pyracantha in naturalizing a slope by excreting its seeds so that, in due course, you will have a firethorn forest.
Tip of the week
The silverberry (Elaeagnus pungens) is not on the radar of most gardeners, but maybe it should be. It is a nitrogen-fixing plant that never needs fertilizer.
Its leaves are not glamorous, although variegated types with yellow blotches or silvery margins are sometimes seen. With no pruning, it eventually grows into a symmetrical mound and does a nice job of controlling erosion on slopes. Although its flowers are invisible, they emit a sweet fragrance.
Both silverberry and firethorn are hardy enough to withstand Antelope Valley winters.

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