Half the fun of plant collecting is seeing how the progeny perform in cultivation.
Some plants reveal their finer qualities slowly, like a complex wine. The three latest introductions from the Santa Barbara Botanic Garden (SBBG) were initially admired for attributes that have been surpassed or superseded by others. These cultivars represent our continuing efforts to develop and introduce outstanding California native plants for gardens. All three are selections from the wild that grow best in full sun and well-drained soils with minimal to no summer water once established.
For decades, West Coast gardeners have been blessed with an abundance of Ceanothus species and cultivars. From prostrate groundcovers to twenty-foot-tall, multi-trunked trees, these quintessential California natives are prized for their frothy blue or white, fragrant flowers. Is there really something unique that has not made the horticultural scene by now? Well, yes, there is. The copious, teardrop-shaped inflorescences of Ceanothus arboreus ‘Powder Blue’ are truly distinct. Collected on Santa Cruz Island for its unusually modest height (less than four feet tall), our oldest specimen of this Channel Islands endemic is now nine feet tall and fifteen feet wide. So much for a bold textured, blue-flowering ceanothus for smaller gardens! Regardless, the arching blossoms and large green leaves are handsome when combined with silvery partners in a mixed border. Try it with Eriophyllum nevinii ‘Canyon Silver’, Eriogonum crocatum, Salvia ‘Bee’s Bliss’, Penstemon spectabilis, and some bunchgrasses for a lively composition.
Many fascinating and ornamental plants occur on both the mainland and western offshore islands of Baja California, Mexico. Several of these species fall within the California Floristic Province, including Salvia cedrosensis, a diminutive maritime desert scrub inhabitant with sky blue flowers. A white-flowered individual from Cedros Island has unpredictably outperformed its blue brethren at SBBG. Named Salvia cedrosensis ‘Baja Blanca’, this rounded, two-foot subshrub has white stems that bear small, gray-green, ovate leaves. It produces four- to five-inch-long inflorescences with mealy/fuzzy buds and milky white, three-fourths-inch blossoms for months on end, and is especially attractive in containers. ‘Baja Blanca’ is a pleasing foil for the boldness of Agave shawii and Dudleya species, as well as providing a bright contrast to the deep green leaves of Rhamnus californica, Arctostaphylos hookeri, or Quercus durata. Although rainfall in its natural habitat is less than ten inches per year, the moderating influence of coastal fog there suggests that this sage may not tolerate the extreme heat of inland desert regions.
The maritime desert scrub vegetation of northwestern Baja contains such familiar California natives as Rosa minutifolia, Agave shawii, Salvia munzii, Acalypha californica, and Dudleya brittonii. A coastal species of Sphaeralcea, whose identity has not been confirmed yet, also occurs here and shares the lovely peach to apricot blossoms and mealy-textured leaves of desert mallow (Sphaeralcea ambigua). Coastal gardeners will want to try the garden’s white-flowered selection, S. ‘La Luna’, since it is much easier to cultivate than its desert relative. ‘La Luna’ was collected on the mainland and has grown surprisingly well in the cooler, wetter microclimates along the central coast of California, surviving temperatures as low as 22° F (‑5° C) with only some tip dieback. The luminous, silky petals of this floriferous clone are tinged with pink, complementing the pink stigma and black anthers. Wand-like flower stalks are produced almost year-round and hold up well in flower arrangements. A planting of ‘La Luna’ with Salvia leucophylla ‘Figueroa’, Rosa minutifolia, and Ceanothus ‘Cal Poly’ at the botanic garden is simply glorious.