Sonoma County Master Gardeners Helping Sonoma Gardeners

Bush Anemone

By Barbara Kirbach, Sonoma County Master Gardener

With either voluntary or mandated water rationing facing Sonoma County gardeners this summer, and perhaps for many summers to come, wouldn't it be great to find a lovely plant that is truly adaptable to our climate and requires very little moisture once established?  Our native Carpenteria californica fits the bill beautifully!

Origins:  Carpenteria californica, or Bush Anemone, is one of California’s loveliest, but rarest shrubs. It is only native to the dry granite ridges of the foothills of the southern Sierra Nevada in the Central Valley near Fresno and is the only species in California.  It was first discovered in the 1840’s by the explorer J. Charles Fremont and was named for an American botanist and physician, William M. Carpenter. In the 1960’s, Wayne Roderick, former director of East Bay Regional Parks Botanic Garden, collected specimens of the shrub, but it was not offered for commercial purposes until the 1980’s.    Its family ties are somewhat clouded.   The Sunset Garden Book and H. Nevin Smith, author of “Native Treasures,” say the shrub is now considered part of the Philadelphaceae family, but ‘Taylor’s Encyclopedia of Gardening’ lists its parents as  Saxifragaceae, insisting that it differs from Philadelphus (mock oranges) in “technical characters” and in being evergreen.  ‘Elizabeth’ is the most available (if not the only) cultivar and is prized for its larger flowers.

Description:  Under ideal conditions, this erect, evergreen shrub can grow 5 to 12 feet tall and 3 to 5 feet in diameter. Its thick, oblong,  3 to 4-inch leaves, which are opposite, are a glossy, dark green on top and whitish on the bottom, making a striking backdrop to the shrub’s showy, white, fragrant 2-inch flowers. From May through July, these loose clusters with as many as 20 blooms at the end of its branches are a spectacular sight. In keeping with its common name, the shrub has flat, anemone-like petals which encase hundreds of bright yellow stamens.  Its fruit contains a number of seeds in a leathery, cone-shaped pod.

Propagation: Marjorie Schmidt in “Growing California Native Plants”, says that Bush Anemone can be propagated from seeds, cuttings from young stems or by suckers.  “Seeds should be sown thinly in a mixture of sand and leaf mold and covered with sphagnum moss to inhibit damping-off,” she advises.  “Seedlings may be transplanted when about 2-inches high and will make rapid growth.  They may be set in permanent quarters when 2-years-old and will begin to flower and fruit after the third year,” she added. However, some experts say propagation can be difficult and we are fortunate to have ready-made plants in our local nurseries.
 
Cultivation: Like most natives, it is best to plant Carpenteria californica in the fall in a sheltered area with high dappled shade and light sun.  The shrub demands good drainage in light, sandy soil, so planting in a raised bed or on a gradual slope is preferable. Do not fertilize.  Because this California native comes from a habitat where summers are long, hot and dry, it can survive on very little water once established.  However, inadequate watering may result in slower growth and fewer flowers.  The first year, Nevin Smith says to water the plant enough to keep its roots moist—two or more deep waterings per month, more in our hot, inland valleys. If you decide to plant in the Spring, when the plant is in bloom and most beautiful, Margaret Graham of Mostly Natives Nursery advises to deep water once a week and then let the soil dry out between times, being sure to use plenty of mulch.  Once the plant is established, cut back on the frequency, so that the top couple inches of soil become fairly dry between irrigations. This native may need less to no water near the Sonoma coast. It is best to use drip irrigation, as overhead watering can cause fungal problems on the plant’s foliage.  The bottom line is that more Bush Anemones perish from over-watering than lack of moisture. 

Pruning:  If pruning is necessary to shape or restrain growth, cut back after flowering for a fuller looking plant. Bush Anemones usually maintain an attractive rounded form, but may become sprawling and rangy with inadequate water or extreme heat.  Unfortunately, hard pruning the older branches may not stimulate new growth, Phil Van Soelen of California Flora Nursery warns.  “Bush Anemones may need to be hand- pruned,” adds Jani Weaver of Emerisa Nursery.   “The shrub is marcescent, which means it is not “self cleaning. Its leaves wither, but do not fall naturally to the ground,” she explains.  Margaret Graham suggests to “prune the shrub as it grows.”

Problems & Diseases:  According to the University of California’s “Pest and Diseases of Small Trees and Shrubs,”  if the shrub develops a sticky honey dew, blackish sooty mold or whitish cast skins and/or its leaves curl and distort, the probable cause is aphids. Inspect new growth regularly and hose off the aphids forcefully with water. Apply insecticidal soap or oil  before the damage occurs.  If you find a thickening of the plant’s twigs and/or its shoots are dead or distorted, it could be pit-making pittosporum scale or brown to white insects 1/8-inch long. This is an occasional problem with no known management. The shrub can withstand normal Sonoma winters, but could sustain damage from continued low temperatures or a late spring frost.

Value in the Garden: Carpenteria californica is a beautiful ornamental, displaying lush, white, sweetly scented blooms over several spring and summer months. In fact, it’s hard to believe that it is not some exotic tropical plant rather than a California native that grows wild in a small range in the Sierra.  The fact that it is a rugged native, requiring a minimal amount of summer irrigation once established, lends its even more value to Sonoma gardeners.   Bush Anemone is also deer resistant, and is said to survive a few nibbles of its foliage. It is beautiful planted as a specimen among a group of conifers or even oaks, as it is resistant to oak root fungus.   However, this charming shrub can also be somewhat temperamental, advises Phil Van Soelen. “It looks its best in the spring and summer.” Jani Weaver concludes, “It’s great when it’s happy, but not when it’s unhappy.” 


Sources:  Carpenteria California can be found in 4-inch and 1- gallon sizes at the following local nurseries: California Flora in Fulton, Mostly Natives in Tomales Bay and  at Emerisa Gardens in Sebastopol.
 

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