Common snowberry is a native, deciduous, shrub that is densely branched. Plants vary in height from 3 to 4.5 feet (1-1.5 m) [50,70,104]. In riparian habitats, common snowberry can reach a height of 6 feet (2 m) [70]. It has a rhizomatous growth habit with rhizomes 2 to 5 inches (5-12.5 cm) deep in mineral soil and commonly forms dense thickets. Flowers are borne in small clusters that produce white drupes. Each drupe contains 2 nutlets with 1 seed per nutlet [50,70,104].
One source [11] reports common snowberry to have a vesicular-arbuscular mycorrhizal relationship in British Columbia. In western Washington, common snowberry has been found to contain allelopathic chemicals [33].
Common snowberry is classified as a "survivor" [71,103] and has high resistance to fire [26,73,84]. It is a rhizomatous species with rhizomes buried 2 to 5 inches (5-12.5 cm) deep in mineral soil [50,70,104]. After fire has killed the top of the plant, new growth sprouts from these rhizomes [77,83,118]. This rhizomatous growth response is highly variable and depends on conditions at specific sites [23,77,84]. Regeneration from buried seed is favored by fires of low severity and short duration that remove little of the soil organic level [23,55].
FIRE REGIMES:
Common snowberry occurs in a wide variety of community/habitat types and plant associations (see DISTRIBUTION AND OCCURRENCE) [15,31,41,42], which have various FIRE REGIMES. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES". Fire-return intervals in communities where common snowberry is most common are provided below.
Across its distribution, common snowberry is classified as dominant or subdominant in a variety of habitat and community types and vegetation associations. Most of these listings are at the warm/dry end of the habitat scale and include classifications as both climax and seral vegetation.
Examples of climax forest habitat types where common snowberry is a subdominant include ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), and subalpine fir (Abies lasiocarpa) [3]. Common snowberry is considered a mid- to late-seral subdominant with ponderosa pine on floodplains in Oregon [68]. Also in Oregon, common snowberry is considered subdominant to Douglas hawthorn (Crataegus douglasii) in a climax tall shrub community type [10] and dominant in a community type with Wood's rose (Rosa woodsii) [67].
Species commonly associated with common snowberry include oceanspray (Holodiscus discolor) in California's hardwood rangelands [4], ninebark (Physocarpus malvaceus) in Oregon [63], bearberry (Arctostaphylos uva-ursi) in south Dakota and eastern Wyoming [3], and Idaho fescue (Festuca idahoensis) in eastern Washington [14].
References describing common snowberry as a community or habitat dominant or subdominant include:
Forest types of the North Cascades National Park Service Complex [2]
Steppe vegetation of Washington Daubenmire 1970 [28]
Ecology of curlleaf mountain-mahogany (Cercocarpus ledifolius Nutt.) in eastern Oregon and adjacent areas [32]
Riparian dominance types of Montana [52]
Forest vegetation of the Black Hills National Forest of South Dakota and Wyoming: a habitat type classification [59]
Riparian reference areas in Idaho: a catalog of plant associations and conservation sites [62]
Ecology and plant communities of the riparian areas associated with Catherine Creek in northeastern Oregon [67]
Vegetation of the Bald Hills oak woodlands, Redwood National Park, California [106]
Common snowberry, like other shrubs, contains a higher percentage of crude protein during fall and winter than grasses or forbs, but lesser amounts during spring and summer. Leaves of common snowberry contain a higher percentage of crude protein than stems. Tips of leaves contain higher protein levels than thicker mid and butt sections [35]. Information presented in the following table is from [35] and is based on seasonal nutritional levels for common snowberry
in the Black Hills of South Dakota:
1 Percentage of oven-dried weight; 2 ADF = Acid-detergent fiber;
3 ADL = Acid-detergent lignin; 4Cell = Cellulose; 5 Calories/gram
Common snowberry, as a rhizomatous sprouter, is among the first to recolonize a site after fire [77]. Growth in the 1st postfire year varies, but is generally considered to be good. With light to moderate soil disturbance, sprouting will return common snowberry coverage in a year [36] and common snowberry may produce fruit the 1st year [16]. Sprout height can reach one-half to three-fourths of prefire stem height in the 1st year and equal prefire height in 4 years [84]. Another source [36] states common snowberry will grow 1 foot (0.3 m) the 1st year. Cover and volume measurements consistently exceed prefire values the 2nd year [84] and canopy cover of common snowberry increases rapidly to a maximum in 3 to 5 years after a fire and may maintain this increased coverage [23,80]. Fire severity and soil moisture content at time of burning may determine damage to the rhizome and root system of common snowberry and be responsible for variation in recovery response [52].
On ponderosa pine and Douglas-fir communities in the Blue Mountains of northeastern Oregon, common snowberry cover and frequency were higher on sites that had been thinned 6 years previously than on prescribed burned, thinned-and-burned, or control sites. Common snowberry was determined to be an indicator species for thinned sites (P≤0.05). For further information on the effects of thinning and burning treatments on common snowberry and 48 other species, see the Research Project Summary of Youngblood and others' [120] study.
Common snowberry can regenerate by seeds, but rhizomes are the primary method of reproduction [50,104]. Rhizomes are occasionally connected in a mass of woody tissue from which multiple stems can regenerate; however, separate rhizomes are usually produced from which single stems arise [17]. Rhizomes sprout after fire or other disturbance kills the top of the plant [64,77,103] and can vary from site to site depending on conditions [64,77,84]. Plants sprouting from rhizomes are among the first to recolonize a site after a fire [64,103] and will often produce fruit the 1st growing season [16]. The rhizome sprout pictured above came from a 3-year-old common snowberry in a garden at the Fire Sciences Laboratory. The rhizome was 6.5-foot (2.0 m) long, and the sprout was 2 feet (0.6 m) tall (Fryer 2011, personal observation).
Seed banks of common snowberry were analyzed in a postfire study [80], but the literature contains very little about postfire regeneration from seed. One study in an east-central Washington ponderosa pine/common snowberry community found common snowberry sprouted from roots, rhizomes, underground organs, or other perennial plant parts, but did not establish from seeds [87]. The seeds of this shrub are commonly dispersed by birds after they eat the fruit [104].
Common snowberry seeds will sprout in a nursery setting [54,78,96]. However, nutlets of common snowberry are extremely difficult to germinate because they have a hard, tough, impermeable covering and only a partially developed embryo [38].
Symphoricarpos albus is a species of flowering plant in the honeysuckle family known by the common name common snowberry.[2] Native to North America, it is browsed by some animals and planted for ornamental and ecological purposes, but is poisonous to humans.
S. albus is an erect, deciduous shrub, producing a stiff, branching main stem and often several smaller shoots from a rhizome. It can spread and colonize an area to form a dense thicket.[3] It reaches 1–2 metres (3+1⁄2–6+1⁄2 feet) in maximum height. The leaves are oppositely arranged on the spreading branches. They are generally oval, differing in size and shape, and up to 5 centimetres (2 inches) long, or slightly larger on the shoots. The inflorescence is a raceme of up to 16 flowers. Each flower has a small, five-toothed calyx of sepals. The bell-shaped, rounded corolla is about 0.5 cm (1⁄4 in) long and bright pink in color. It has pointed lobes at the mouth and the inside is filled with white hairs. The fruit is a fleshy white berry-like drupe about 1 cm wide which contains two seeds. The plant sometimes reproduces via seed but it is primarily vegetative, reproducing by sprouting from its spreading rhizome.[3] Birds disperse the seeds after they eat the fruit.[3]
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Plant
Leaves
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Buds
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Fruit
S. albus var. laevigatus
There are two varieties:
S. albus occurs across much of Canada and the northern and western United States.[4][5]
It grows in shady and moist mountain and forest habitat, in woodlands and on floodplains and riverbanks. It can grow in a wide variety of habitat types.[3] It is naturalized in parts of Britain, where it has been planted as an ornamental and cover for game animals.[6]
This shrub is an important food source for a number of animals, including bighorn sheep, white-tailed deer, and grizzly bears.[3] Livestock such as cattle and sheep readily browse it.[3] Many birds and small mammals use it for food and cover.[3] Pocket gophers dig burrows underneath it during the winter.[3]
The fruit and shrub are poisonous to humans, causing vomiting.[7]
Native Americans used the plant as medicine, soap, sometimes for food, and the wood was good for arrow shafts.[3] In Russia, the berries are crushed in the hands and rubbed about for a soothing folk-remedy hand lotion.
This shrub is used for erosion control in riparian areas, and it is planted in ecological restoration projects on disturbed sites such as abandoned mines.[3] Its white fruits and blue-green foliage made it popular as an ornamental plant[3] planted around old houses of the 1890s through the 1920s like with the Vanhoutte Spirea or Bridalwreath. It is still sold by some large diverse conventional nurseries and native plant nurseries, and occasionally found in modern landscapes. It grows in full sun to full light shade and a well-drained soil that is slightly acid to well alkaline, pH range of about 6.0 to 8.5. it is easy to transplant with its fibrous, shallow root system. It fares well in U.S. Department of Agriculture hardiness zones of 2 to 7.
Symphoricarpos albus is a species of flowering plant in the honeysuckle family known by the common name common snowberry. Native to North America, it is browsed by some animals and planted for ornamental and ecological purposes, but is poisonous to humans.
