Evergreens: framing your landscape!
Written for the Davis Enterprise, November 2001
Recently I've been in many new yards that seemed to lack substance. The lawns were in. The shade trees had been placed carefully, and there were nice flowers and ground covers. But the fences were blank: the evergreen shrubs and trees that help to frame the yard and provide privacy were missing. These plants are usually not showy, although some do have seasonal flowers, but they look good year-around. We especially appreciate them in the winter, when shade trees are bare and perennial flowers are dormant. Some provide seasonal contrast with colorful foliage or berries, and they can be used in flower arrangements or holiday wreaths.
Except for some pines, coniferous trees don't grow naturally here because most of them require more than 30" of rainfall per year. Some of the unusual conifers you see flourishing in Oregon or the Bay area don't like our water: False cypress (Chamaecyparis spp.) and Cryptomerias are generally not successful. But Deodar and Atlas cedars (Cedrus spp.), Incense cedar, and Italian cypress all do well here and are reasonably drought tolerant once established. There are good examples of the cedars and Coast redwoods throughout the Stonegate development in West Davis, and blue Atlas cedars are planted along Covell Blvd. and in front of the fire station on Fifth Street.
Coast redwood is very popular as a fast screen or windbreak, and flourishes as long as it gets plenty of water. Look for selected cutting-grown clones for uniform color and growth habit. The closely related Giant Sequoia (Sequoiadendron giganteum) invariably succumbs to a fungus disease on this side of the Valley. Among the pines, Scotch pine, Japanese black pine, Austrian black pine, Canary Island pine, and Torrey pine are among the best for average-sized yards. The first three species make great living Christmas trees. Italian stone pine grows very happily here but is a huge, broad-spreading tree--too large for most yards! There are good examples near the Ruth Storer garden at the west end of the Arboretum. Aleppo pines were widely planted many years ago, and can be seen lining Catalina Ave. in North Davis. You might notice that many of them seem to be slowly falling over! Root problems in wholesale production seem to be a common problem with this tree.
Spruces are popular as living Christmas trees because they grow slowly and maintain their compact pyramidal shape. The most successful here are the Colorado green and blue spruces (Picea pungens and P. pungens 'Glauca'). Give them plenty of water and some shade from the hottest West sun; they can live in an oak barrel to be decorated year after year.
Most of the non-coniferous evergreens are versatile in the landscape. They can be pruned up as trees or pruned down as shrubs, and are among the best for providing privacy.
Bay laurel (Laurus nobilis) has dark, lustrous leaves that are used in cooking; branches make great holiday wreaths or as filler in flower arrangements. Our native bay tree (Umbellularia californica) is much slower-growing. Strawberry trees (Arbutus unedo, or the variety Arbutus 'Marina') have a dense growth habit, a profusion of pretty, small white flowers, bright orange fruit that attracts birds, and a beautiful mahogany trunk that resembles our native and closely related Madrone (Arbutus menziesii).
If you want the look of a weeping willow, some smaller evergreens include African sumac (Rhus lancea), and Peppermint gum (Eucalyptus nicholii). There are some very nice African sumacs on the south end of Marina Circle, just off Lake Blvd. in West Davis, and a mature Peppermint gum on the corner of Loyola and Adrian in East Davis. Chilean mayten (Maytenus boaria) is a similar willow-like evergreen, but many of them in the area are suffering from a dieback the cause of which is not clear to me (attention plant pathologists--any idea what this might be? Botryosphaeria?).
Two of the most successful evergreens to provide privacy and a sense of enclosure are Shiny xylosma (Xylosma congestum) and Mock orange (Pittosporum tobira, also available in a variegated form). Both grow very easily with no special care, can be trained as small trees or trimmed as formal hedges, or simply allowed to grow naturally into large, graceful shrubs. Xylosma in particular is very drought and heat-tolerant, and Pittosporum has white flowers that smell like orange blossoms (hence the common name). Red-tip Photinia (Photinia 'Fraseri') is very popular for the bright red spring growth, but it is being overused to the point that pest problems are showing up--lace bugs and fireblight are an increasing problem.
Holiday greenery from the garden!
Hollies (Ilex species) have shiny leaves that stand out in the garden in the winter, and of course have bright red berries that are traditional holiday decorations. Variegated English holly (Ilex aquifolium 'Variegata') is the most familiar, but you need a male and a female plant for reliable berry production. Other varieties are available that set fruit without cross-pollination. Hollies prefer regular watering, shade from the hottest sun, and occasional feeding with an "acid-type" fertilizer. They make an excellent background shrub on a north-facing wall.
There are lots of other plants for holiday berries. Heavenly bamboo (Nandina domestica) comes in many selected forms that vary primarily in how tall they get. Cold nights cause the leaves to turn bright red, just as the berries turn bright orange. The many species of Cotoneaster and Pyracantha have berries that vary from orange-red to the color of cranberries. These range from low ground-covering shrubs to large, dramatic background shrubs. Pyracanthas are thorny and can be prone to fireblight disease; Cotoneasters are neither. Interestingly, Pyracantha berries that hang on late into the season can eventually ferment--the plantings along Highway 50 were taken out years ago because inebriated pigeons kept staggering out onto the road! Our native Toyon (Heteromeles arbutifolia) is sometimes called Christmas berry because of the profusion of bright red fruit in the winter.This slow grower prefers very infrequent summer irrigation once established.
Other evergreen shrubs
This covers just a fraction of the useful evergreen shrubs. For shade, try Sarcococca for fragrance or Mahonia aquifolium for colorful flowers and berries that attract birds. Osmanthus fragrans also has powerfully fragrant flowers and prefers light shade. Viburnum tinus has blooms in the winter and can take full sun or light shade; Viburnum suspensum has blooms in early spring that have a fruity, musky perfume.
When you design your yard think of a house and create outdoor living spaces. If the trees provide the roof, the lawns and ground covers are the floors and rugs, and the perennial flowers are the wallpaper and decorations, then the shrubs are the walls (o.k., dear editor, I am stretching the metaphor!). Choose them for substance, texture, and subtle seasonal changes to provide the proper atmosphere all year.
© 2008 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616
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