Holodiscus dumosus

Holodiscus dumosus
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Rosales
Family:	Rosaceae
Genus:	Holodiscus
Species:	H. dumosus
Binomial name
Holodiscus dumosus (Nutt. ex Hook.) A.Heller

Holodiscus dumosus is a species of flowering plant in the rose family, with the common names mountain spray, rock-spiraea, bush oceanspray, and glandular oceanspray.

Description

Holodiscus dumosus is a deciduous spreading shrub, which grows from .5–6 meters (1+1⁄2–19+1⁄2 feet) in height and 1.5–3 m (5–10 ft) in width. The stems intricately branch from the root crown and spread outward. The branches have shreddy bark and the smaller reddish twigs may be slightly spiny. The aromatic leaves are up to 2.3 centimeters (7⁄8 inch) long by 1.2 cm (1⁄2 in) wide. They are lobed or toothed.

The inflorescence is a feathery panicle of small, pinkish-white to cream colored flowers, each about 2 millimeters long. The bloom period is June through August. They are insect-pollinated.

Small seeds are produced in tiny, dry capsules. They are dispersed by the wind. The plant reproduces by seed and by sprouting from its root crown.

Varieties

• Holodiscus dumosus var. cedrorus — endemic to serpentine soils in The Cedars area of Sonoma County, California.
• Holodiscus dumosus var. dumosus — native to Colorado, Arizona, Nevada, Utah.
• Holodiscus dumosus var. glabrescens — currently reclassified as Holodiscus discolor var. glabrescens.

Distribution and habitat

The plant is native to western North America, where it occurs in northern Mexico and the Western United States.

It grows in many types of forest and shrubland habitats, and plant communities. For example, it is characteristic of and sometimes dominant in the understory of Douglas-fir, Ponderosa pine, and Arizona pine forests and oak woodlands. It grows from 910–3,630 m (3,000–11,900 ft) in elevation, depending on latitude and climate.

In Colorado, New Mexico, Wyoming, and Idaho it occurs in the Rocky Mountains. It has been called "nearly ubiquitous" in many plant communities in Utah. In Arizona it occurs in the mountain wilderness of the Madrean Sky Islands such as the Chiricahua Mountains, sometimes in scree with Douglas-fir, and is a common plant in the Grand Canyon. In Nevada it is a component of quaking aspen and willow communities and sagebrush of the Great Basin region. In Mexico it is native to the states of Chihuahua and Baja California. It is also native to northern California and Texas.

The shrub tolerates a variety of soil types, as well as bare rock and rock fragments, such as crevices in cliffs and scree. It is drought-tolerant and survives in dry habitat, but it thrives in more moist locations, and can be found in wetter environments than its relative, Holodiscus discolor (creambush oceanspray). It can be found in cool, moist mountain forests in the central part of its range. It prefers sheltered locations that have less direct sunlight and wind. It anchors easily on steep slopes, and can grow on vertical topography, such as cliffs.

Uses

Native American peoples such as the Paiute and Shoshoni utilized this as a traditional medicinal plant for ailments such as stomachaches and colds.

Early immigrant explorers used the wood to make nails.

Cultivation

Holodiscus dumosus is cultivated as an ornamental plant, used in part-shade wildlife gardens, natural landscaping design projects, and as a large container plant.

External links

• USDA Plants Profile for Holodiscus dumosus (rockspirea)
• UC CalPhotos Gallery of Holodiscus dumosus