* Editor’s note: This is part of a continuing series of articles on plants that can grow and look good with low water. The focus here is on low to medium shrubs for very limited irrigation, especially natives. Low-water taller shrubs were discussed in the November 2011 article.
By Don Shor
Note that some California native plants require drought, as compared to tolerating drought. They’ll die if you water them too often.
In garden references you’ll sometimes see the notation “needs good drainage” or “short-lived.” Those are code for “susceptible to crown rot,” meaning that if they get watered too frequently in warm weather they may get attacked by Phytophthora, a fungus-like organism that invades the plant at the crown and kills it swiftly. Many, but not all, of our native plants are vulnerable.
Watering deeply and infrequently, and avoiding mulch around the stem, are the best practices for avoiding crown rot.
Low and ground-cover shrubs
* Botanical name: Arctostaphylos species
Common name: Manzanita
As a group, I am leery of manzanitas because they are so easy to kill, being very sensitive to overwatering. But a couple of garden cultivars are less vulnerable. Howard McMinn grows to about 3 feet tall, 4 feet wide or more. It has a dense growth habit, with shiny green leaves that contrast nicely against the red stems.
* Baccharis pilularis Twin Peaks
Dwarf coyote brush
Very tough, drought-tolerant native. Great for attracting beneficial insects. Otherwise a dull, somewhat scruffy-looking plant. Unbelievably resilient, so it earns its place on my list on that account. Nobody’s going to say, “ooh, look at your coyote brush!” But you don’t ever have to prune or even water it.
* Ribes viburnifolium
Will grow in considerable shade, spreads steadily to make an attractive ground cover. Fragrant evergreen foliage. Light pink flowers in late winter attract hummingbirds; small red berries attract songbirds.
Botanists recognize hundreds of species in the genus Salvia, possibly up to a thousand. While most gardeners know Salvia officinalis (garden sage, from Europe) used in cooking, more than half of the species are from South and Central America, with a few species from California and the Southwest. Some types are frost-tender and prefer regular watering. A few like some shade. But our native species and their hybrids are generally very tolerant of drought and hot sun.
The flowers of Salvias are fascinating up close. They are “bilabiate” which means “having two lips.” There are often glandular hairs on the flowers and leaves. The stamens are fused into a lever, which bends down and deposits the pollen on the back of the visiting bee or bird as it probes the long flower tube. The female flower stigma develops next and is bent down to receive the pollen. The flower is adapted to many pollinators, rather than any specialized one.
Salvias are always active with wildlife. Hummingbirds, butterflies, carpenter bees and bumblebees are attracted to the flowers. Beneficial insects harbor on the foliage. Songbirds like the small seeds. A mixed planting of salvias, lavenders, rosemary and daisies will give year-around color, help prevent garden pests, enhance pollination, and require very little water once established.
* Southwestern native sages
Salvia greggii, S. microphylla, and more. These are the stars of the autumn garden, at their peak of bloom right now.
For gardeners, this is one plant group where there has been a sea change in availability of species, hybrids and cultivars in the last couple of decades. My 1970 edition of the “Sunset Western Garden Book” lists 10 species on about half a page, with only three cultivars. Native plant specialists carried a couple of species. In the herb section of your local garden center you could find common garden sage for use in your holiday turkey stuffing. Annual scarlet sage was a popular summer bedding plant. That was about the extent of the Salvia trade.
Then in the early 1990s, Salvia greggii, now called autumn sage, started to show up. No named varieties, but it caught on quickly for the bright pink late summer and fall blooms. Now Salvias cover six pages in the 2012 edition of “Sunset.” One grower has 30 to 40 varieties available.
What makes these important for valley gardeners is that many of them come from hot, low-rainfall regions. Salvia greggii is native to the high deserts of southwest Texas and Mexico. Salvia microphylla, Graham’s sage, comes from southeastern Arizona and Mexico (it is recognizable by the much more fragrant foliage, which occurs in some of its progeny). When you bring these two together in a garden, they hybridize very readily and reseed happily. So now there are dozens of natural and intentional hybrids, in an ever-increasing range of colors.
For taxonomy buffs: the original hybrids between S. greggii and S. microphylla were given the name Salvia x jamensis. The “x” indicates an inter-specific hybrid of known parentage. But that was a while ago. The exact parentage of many of the new cultivars is simply unknown at this point, so they often just have a cultivar name; e.g., Salvia ‘Dark Dancer.’ The genus name (Salvia) is properly italicized; the cultivar name should be in single quote marks. Neither is standard editorial practice in the news industry, but it is how you will usually see the name in journals and reference books.
Hybrids and cultivars in this complex group are generally 2 to 4 feet tall and wide. Most branch heavily from the base. S. greggii types tend to get woodier and taller, eventually a little rangy. You can cut these back in spring to keep them shorter and more compact. The bloom is light and steady in spring and summer, and absolutely profuse in fall.
The color range started in reds and pinks, then broadened to lavenders and purples. A light yellow form appeared; now there are some stronger yellow ones.
Every time I think I have a favorite, another variety comes along. In addition to those shown here, I have created a Pinterest board of my Salvia pictures: http://pinterest.com/redwoodbarn/salvias.
California native sages
Mostly spring-blooming, these have denser growth habits than the previous species and tend to get larger.
* Salvia apiana
Silvery-white leaves give this the common name of white sage. Three feet tall and wide; white flowers, intensely fragrant foliage. Hardy to 20 F or lower. This is the one used for burning in purification rituals. Hard to propagate and thus not common in the trade. It is easy to kill by overwatering.
* Salvia clevelandii
Cleveland sage is a Southern California native that grows to about 3 feet tall and a little wider. It has attractive gray-green foliage, and tall whorls of blue flowers in late spring. A very useful shrub in low-water landscapes, it combines well with non-native low-water plants such as Cistus (rockrose), lavenders and rosemary, as well as natives such as Ceanothus (wild lilac) and manzanita. A few cultivars: Allen Chickering has lavender-blue flowers; Winnifred Gilman’s are darker blue.
I have found this plant often harboring ladybugs in the adult and larva forms in winter and early spring.
A few other native shrubs
* Carpenteria californica
This slow-growing, tidy shrub to 4 to 5 feet, from our coastal mountain range, has shiny leaves and a compact growth habit. White showy flowers in late spring resemble anemones. Tolerant of sun or light shade.
Attractive shiny leaves and fragrant blue flowers in spring. Water deeply and very infrequently in summer; they are notorious for dying abruptly in warm weather when they get watered too often.
There are low spreading types. Centennial stays under a foot tall and spreads several feet. Yankee Point grows to 2 to 3 feet tall and spread 6 to 8 feet or more.
The UC Davis Arboretum touts Valley Violet, a well-mannered low shrub with small leaves and unusual lavender-pink flowers.
Several varieties grow to 6 feet or so, some spreading wider. Julia Phelps has dark, small leaves and vivid cobalt-blue flowers; one of the showiest in bloom.
Ray Hartman, mentioned in the Nov. 11 article, is big, fast and upright, tall enough to train as a screen or small tree to 15 to 20 feet.
* Mahonia aquifolium
Native to the coast side of the coastal mountain range. Shiny leaves, bright yellow flowers in winter, blue berries that attract songbirds. Tolerant of sun but better-looking in some shade and tolerant of deep shade. Compacta is a denser, shorter variety. John Muir and Ken Hartman (a hybrid) are selections with denser foliage, spinier leaves.
* Romneya coulteri
Matilija poppy; Fried egg flower
Really a very large herbaceous perennial, this gets big enough that we group it with shrubs. The plant has coarse-toothed blue-green leaves on stems which culminate in a cluster of very large poppy flowers. The white petals and yellow stamens look like nodding fried eggs. The rhizome roots spread steadily to cover a pretty wide area over time. Tolerant of complete drought, full sun, some shade.
As you change over your landscape for lower water use, consider some of these plants native to California and the Southwest for their durability and beauty.
— Don Shor and his family have owned the Redwood Barn Nursery since 1981. He can be reached at [email protected]. Archived articles are available on The Enterprise website, and they are always available (all the way back to 1999) on the business website, www.redwoodbarn.com