Adaptation: It is a common associate in successional coastal shrub communities, but also occurs as an understory shrub in coniferous forests ranging from the coast to the western slopes of the Cascade Range. Its general geographic range is characterized by cool, relatively dry summers and wet winters with precipitation ranging from 50 to 120 inches per year. Hairy manzanita prefers well-drained, acidic soils in open sunny sites. It has a mild frost tolerance, but a low tolerance for frozen soils. Fire may be important to successful seed germination and establishment, especially in coastal shrub communities and relatively open forest communities.
Natural Establishment: Arctostaphylos columbiana, like most manzanita species, requires insect visitation to ensure seed-set. Bees that grasp the flower and shake it by actively beating their wings pollinate the flowers. This process, like shaking a salt and pepper container, permits efficient collection of the pollen, which is used for food. Fruits are dispersed primarily by animals, which presumably aid germination by digesting the fruit and softening the outer seed coat. However, natural germination is sporadic except after fire, which cracks the hard coat of seeds that have accumulated in the litter layer. Hairy manzanita prefers loose, well-drained soils and, like other members of the heath family (Ericaceae), has an obligate relationship with mycorrhizal fungi.
Seed Propagation: Propagation from seed is difficult, because of the thick, bony seed walls and low rates of germination (less than 10%) without treatment. However, if propagation from seed is desired, treatment must ensure that the seed coat is broken without damaging the embryo. Individual seeds may be filed with a steel file, but larger quantities can be treated by placing them into a container of boiling water that is removed from the source of heat after 1-2 minutes. Seeds also respond well to burning, which is accomplished by firing a 4-inch deep layer of combustible leaves and twigs over a flat planted with seeds. These treatments crack the seed coats but may reduce viability. Treated seeds should be stratified in a moist mix of milled sphagnum and beach sand for 2-8 months until they germinate. Other techniques, including use of sulfuric acid to soften the seed coat, may enhance germination, but also requires special precautions against spillage and contamination.
Vegetative Propagation: Vegetative propagation is preferred over seeds. Cutting terminal shoots that include 1-2 inches of the woody stem from the previous year most easily propagates hairy manzanita. Cuttings work best if taken between January and March and should be dipped in a rooting hormone before being placed in a moist sand-peat mixture. Cuttings need to be kept moist by regular watering or misting until roots appear. Once rooted, they should be transplanted into small containers using potting soil, to allow for proper root development. Manzanitas generally do not transplant well, so they should be grown to vigorous conditions in one-gallon containers and then moved to a permanent position in the late fall or early winter. Relatively slow growth rates during the first few years can be expected. If plants are used in an urban landscape, the use of organic-rich soils and acidified fertilizers is recommended.
