We are pleased to announce the second offering of the Pacific Plant Promotions program: Monardella macrantha ssp. macrantha ‘Marian Sampson’, an outstanding cultivar of one of the most colorful of California’s native perennials.
This choice evergreen perennial is particularly well suited for rock gardens and containers, though it may be grown as a small scale filler or accent at the front of a border. It develops into a loose mat approximately four inches tall and eighteen inches or more across, though wider plants have been seen. Hummingbirds are strongly attracted to the rich nectar of the red orange tubular flowers. Unlike many California native plants, Monardella macrantha ssp. macrantha ‘Marian Sampson’ flowers during the summer months, from June through August.
This unusual plant requires different garden conditions from those preferred by many of the more commonly encountered California native plants. Grow this monardella in bright partial shade (full sun in gardens near the coast) in well-drained soil. In low-elevation gardens, it will benefit from an occasional summer watering, once it has become established; if kept too dry through the summer, it will not survive. Cold hardiness is not a problem: it can be grown reliably in Sunset zones 3 to 9 and 14 to 24. It is generally not a long-lived plant—a life span of about four years in the open garden is typical although plants grown in containers live much longer. In containers, it will send out runners that may emerge from the drainage holes. Additional plants can easily be propagated either by division or from cuttings of vegetative shoots. Plants may need protection from rabbits, ground squirrels, or other rodents.
In nature, Monardella macrantha ssp. macrantha is found between 2,000 and 6,500 feet elevation from the Santa Lucia Mountains of California south to the Sierra San Pedro Martir of Baja California, Mexico. Throughout its range, this monardella is generally found in cooler, partially shaded environments that may receive moisture during the summer monsoon season, when occasional storms move into Southern California from Mexico.
This is but one of the forty-four taxa of Monardella native to California. Within its range, it will be found in chaparral, woodland, and forest communities, most reliably in association with a melic grass (Melica imperfecta); other herbaceous plants with which it associates naturally are a California fescue (Festuca californica var. parishii), Linanthus floribundus, Phacelia imbricata ssp. patula, Polystichum imbricans ssp. curtum, and Sedum spathulifolium. Native shrubs in its company include coffeeberry (Rhamnus californica), mountain pink currant (Ribes nevadense), and snowberry (Symphoricarpos rotundifolius var. parishii); and all will be found with trees such as white fir (Abies concolor), Coulter, Jeffrey, and sugar pines (Pinus coulteri, P. jeffreyi, and P. lambertiana), bigcone Douglas fir (Pseudotsuga macrocarpa), and both coast and canyon live oaks (Quercus agrifolia and Q. chrysolepis).
Monardella macrantha ssp. macrantha ‘Marian Sampson’ is an evergreen, lax, loosely matting, rhizomatous perennial, 4 inches tall and 12 to 18 inches wide. A single inflorescence measures 21⁄4 inches long and 11⁄4 inches wide and resembles an old-fashioned shaving brush. There are up to twenty-five erect, narrow, tubular, red-orange flowers tightly bunched together in each flower head. A single flower is 13⁄4 inch long and 1⁄8 inch wide. The stamens and stigma are exserted about 1⁄8 inch beyond the five short corolla lobes. Showy red purple bracts, up to 1⁄4 inch wide and 1⁄2 inch long, subtend each inflorescence. Each flower has a showy, tubular, red purple calyx, 7⁄8 inch long. The shiny mid-green stems and leaves are often suffused a pale red purple. The leaves are variable in size from 1⁄4 to 11⁄2 inches long and from 1⁄8 to 1⁄2 inch wide. The larger leaves have long petioles (nearly half the length of the leaf). Unlike most monardellas, the leaves of M. macrantha ssp. macrantha ‘Marian Sampson’ are not pleasantly aromatic, though they do have an unusual light scent that is difficult to classify.
Monardella macrantha ssp. macrantha ‘Marian Sampson’ originated as a seedling grown and selected by Ed Sampson of Mourning Cloak Ranch and Botanical Garden in Tehachapi, California, in the early 1990s. The seed that yielded this selection was collected in the Santa Rosa Mountains of Riverside County and distributed by the Theodore Payne Foundation. The plant has been such a star performer in widely scattered gardens in the West that Ed named it in July 2000 in honor of his late wife, Marian, who was co-director of Mourning Cloak Ranch and Botanical Garden. To a large extent, she was responsible for much of the garden’s success. She took great delight in many California native plants and M. macrantha was a particular favorite of hers because it attracted so many hummingbirds.
Monardella ‘Marian Sampson’ has sparingly been in the nursery trade as an unnamed selection of M. macrantha since 1995. She is the most vigorous, free flowering, and disease resistant selection of M. macrantha that I have ever encountered or grown. The disease resistance is of particular note, as this is the only selection that has proven immune to a devastating rust that usually kills other plants of this species within their first year of cultivation.
Rancho Santa Ana Botanic Garden will be offering cutting-grown plants of Monardella macrantha ssp. macrantha ‘Marian Sampson’.