By Susan Lewitt, for Let’s Talk Plants! January 2024.
Keystone Species Revisited - Manzanitas Supporting Biodiversity and Beauty
Keystone species? They are like the backbone of nature and when they are preserved and encouraged, many other native species thrive along with them. Two such genus are Arctostaphylos and Xylococcus, both commonly known as Manzanita. I have chosen five to highlight here that have been available at Neel’s Nursery. Many Manzanita species are sold at the San Diego Chapter of California Native Society’s annual fall plant sale, as well as several other local nurseries. If you are going for specific species, you should always call the nursery first to check if it is currently in stock. Neels’s Nursery, Moosa Creek, and Native West usually stock some popular Manzanitas.
Big Berry Manzanita, Arctostaphylos glauca, is very available in local nurseries, and also occurs widely throughout southern California all the way to San Francisco. It also does well near California Juniper, Juniperus californica, Rabbitbrush, Ericameria nauseosa, California Buckwheat, Eriogonum fasciculatum, Coffeeberry, Frangula californica, Hollyleaf Redberry, Rhamnus ilicifolia, Big Sagebrush, Artemisia tridentata, Chamise, Adenostoma fasciculatum, Oaks, Quercus spp., and sages, Salvia spp. It is a keystone species because of its relationship with other plants, and also its supporting role for bats, caterpillars, and butterflies. There are five butterfly and moth species that rely on this plant and possibly forty-eight more that are likely visitors. It is moderately easy to care for, requiring only a once-a-month summer watering, once established. Place it in fast to medium draining soil, and full sun. On slopes it can be in heavy soil that is rocky but not facing south.
What do you get if you have a Big Berry Manzanita? This plant may grow as a bush if kept to about three feet tall by six feet wide, or one the size of a small tree slowly growing up to twenty feet tall by twenty feet wide! The smooth red barked branches twist as they grow. The light gray-green leaves last year-round with flowers of pink and white occurring in the winter, and spring, followed by light red egg-shaped berries. And it is edible! Patience is important with this long-lived plant because it will bear fruit when it is about twenty years old but lives about one hundred years.
Del Mar Manzanita, Arctostaphylos glandulosa ssp. crassifolia, is another local but rare species. Its availability is very limited, but it is an indigenous species worth finding. In the wild, it is found mainly in the Southern Coast region of California, usually on rocky outcrops, crests and hills. It occurs in the southern maritime chaparral community along with other sporadically seen species. Possible companion plants include Summer Holly, Comarostaphylis diversifolia ssp. diversifolia, Mission Manzanita, Xylococcus bicolor, Scrub Oak, Quercus dumosa, California Encelia, Encelia californica, Chamise, Adeostoma fasciculatum, Coastal Pricklypear cactus, Opuntia littoralis, Mojave Yucca, Yucca shidigera, and Tree Poppy, Dendromecon rigida.
This charming relatively easy to grow plant will have varied leaf colors of pink, silver, blue, and green, depending on the season. It may only get to four feet tall in a loose mounding form but has been known to reach eight feet in height. In either case, it will cover about six feet in width. It is slightly fragrant and evergreen growing at a moderate rate. Look for cream and pink flowers in the winter and spring. It is considered a keystone species because of all the wildlife it supports including birds, and hummingbirds, bats, bees, caterpillars, and butterflies. There are twenty-nine butterfly and moth species that most likely visit this Manzanita.
You can attract all that wildlife by having the Del Mar Manzanita growing happily in your garden as bank stabilization, or ground cover. It should not be watered once established and should be situated in full sun to part shade, in medium to fast draining soil. You may prune this lightly to help shape it as needed, including trimming off any branches that die back. The plant will not be harmed if these leafless branches remain. It also grows back quickly after fires, but I recommend that you don’t test this in your garden.
One Manzanita was named, not for its color, but for where it is found: The Rainbow Manzanita, Arctostaphylos rainbowensis, occurs mainly in Rainbow, and from Northern San Diego, all the way north to the southern Riverside Counties. It grows on slopes, in the lower elevation coastal mountain chaparral. Not only is its distribution limited, but it is also the only Manzanita in its range.
The Rainbow Manzanita is a rounded upright shrub that will grow from 3 to 13 feet tall, by about 3 to 16 feet wide, at a moderate rate. This evergreen shrub has pink and white flowers during the winter and spring. It supports birds, including hummingbirds, bats, bees, caterpillars and butterflies. There are 29 moths and butterflies that may have been seen frequenting this plant.
The Rainbow Manzanita will work well with chaparral and coastal sage scrub species. Possible companions include California Copperleaf, Acalypha californica, Chamise, Adenostoma fasciculatum, California Adolphia, Adolphia californica, Coyote Brush, Baccharis pilularis, San Diego Viguiera, Bahiopsis laciniata, Nevin's Barberry, Berberis nevinii, Ceanothus spp., Mountain Mahogany, Cercocarpus spp., Bushrue, Cneoridium dumosum, Bush Poppy, Dendromecon rigida, Buckwheat, Eriogonum spp., Yucca, Hesperoyucca whipplei and Yucca shidigera, Bush Mallow, Malacothamnus spp., Sage, Salvia spp., and Woolly Bluecurls, Trichostema lanatum. It likes full sun with medium to fast draining soil that is sandy, or decomposed granite commonly known as DG, and only a once-a-month summer watering once established.
Another indigenous Manzanita is the Otay Manzanita, Arctostaphylos otayensis, which may be carried by a couple nurseries. You may find it in San Diego Counties Otay Mountains, and possible in Northern Baja. This moderately growing shrub will reach three to eight feet tall by roughly ten feet wide. It is a mounding rounded evergreen shrub that has pink and white flowers during the winter and spring. It has been used as a hedge.
Plant the Otay Manzanita in full sun, or partial shade. Once established, it only needs watering twice a month during the summer. It does well in a variety of medium draining soils. Native plant species that will grow with it include Chamise, Adenostem fasciculatum, San Diego County Viguiera, Bahiopsis laciniata, Manzanita, Arctostaphylos spp., Coastal Sagebrush, Artemisia californica, Coyote Brush, Baccharis pilularis, Ceanothus spp., Common Sandaster, Corethrogyne filaginifolia, Dudleya spp., California Fuchsia, Epilobium canum, Buckwheat, Eriogonum spp., Mexican Flannelbush, Fremontodendron mexicanum, Tecate Cypress, Hesperocyparis forbesii, Lupinus spp., Penstemon spp., Bladderpod, Peritoma arborea, Oaks, Quercus spp., Matilija Poppy, Romneya coulteri, White Sage, Salvia apiana, Munz's Sage, Salvia munzii, Woolly Bluecurls, Trichostema lanatum, Yucca spp., and cactus species. It supports caterpillars and butterflies with a possible twenty-five butterfly and moth visitors.
For botanical reasons, the fifth charming species is in a different genus and known as Mission Manzanita, Xylococcus bicolor, and occurs in a limited area around San Diego County, and a bit beyond. It has been carried by local native plant nurseries. This shrub reaches between five to twenty feet tall, and five to twenty feet wide. It grows slowly, and is semi-summer deciduous, with softly fragrant pink, and white flowers from winter through spring. It has been used for bank stabilization and is deer resistant.
In full sun and medium draining soil, this plant once established will need watering once a month during the summer. Companion plants include Sugar Bush, Spiny Redberry, Black Sage, Hoaryleaf Ceanothus, Ceanothus crassifolius, Woollyleaf Ceanothus, Ceanothus tomentosus, Chaparral Whitethorn, Ceanothus leucodermis, Chamise, Scrub Oak, and Mountain Mahogany. It supports bees, and birds, including hummingbirds.
Local nurseries carry a wide variety of Manzanitas, many of which are hardy, but not necessarily indigenous to San Diego. Landscapers and nurseries are always willing to help you decide which of the many Manzanitas work best for your garden.
For a couple other available Manzanitas, see “GOING WILD WITH THE NATIVES: Make Mine Manzanita”, from Aug 28, 2019, which talks about Pacific Mist Manzanita, Arctostaphylos ‘Pacific Mist’, and Louis Edmunds Baker's Manzanita, Arctostaphylos bakeri 'Louis Edmunds'. Both of these are found in many California nurseries, and support wildlife. For even more information, Calscape is a great source.
Susan Lewitt is a member of the California Native Plant Society (CNPS), participating in their Native Gardening Committee, and their Conservation Committee.
Comments