Holodiscus dumosus is an erect shrub with hundreds of small white flowers in an obvious inflorescence. It is usually seen at upper elevations in mixed conifer forest along the roadside with the inflorescence bending in towards the roadway.
Common Name: rockspirea
Duration: Perennial
Nativity: Native
Lifeform: Shrub
General: Spreading shrub to 3 m, with smooth, reddish-brown bark, densely to intricately branched, main foliage on spur branches.
Leaves: Alternate, aromatic, ovate with few divisions of rounded teeth, pubescent, dark green above, whitish green beneath, veins obvious on the underside, leaves gathered in clusters on each raised, scarred node on mature branches, or singular on younger branches, blades 0.5-3 cm long, less than 2.5 cm wide, obovate to oblanceolate or elliptic, cuneate at base.
Flowers: Tiny white flowers form a spray of axillary, racemose clusters, hemispheric hypanthium with sepals about 1.5 mm long, sometimes pinkish, petals about 2 mm long, white, cream or pinkish, 5 pistils and numerous stamens, the pedicels and petals pubescent.
Fruits: Hairy 1-seeded follicle.
Ecology: Found on rocky substrates on cliffsides and in coniferous forests, from 5,500-10,000 ft (1676-3048 m); flowers June-September.
Distribution: Ranges across Arizona and New Mexico and south into northern Mexico.
Notes: This is a lovely plant which puts on a great show when in flower. The abundant white sprays can be seen from a distance, and the aromatic flowers yield a heady scent. To distinguish it from H. discolor pay attention to the way the leaf blades are decurrent on the petiole, or tend to come down the petiole.
Ethnobotany: Decoction of roots taken for diarreah and stomache disorders. Decoction of stems taken for colds and as an emetic. Decoction of leaves and stems used for stomachaches, an emetic, eyewash (with flowers), and venereal disease.
Synonyms: Holodiscus discolor var. dumosus
Editor: LCrumbacher, 2011
Etymology: Holodiscus comes from the Greek holos, "entire," and diskos, "a disk," the disk unlobed (ref. genus Holodiscus), and dumosa means bushy, shrubby.
