Summary ⁴

Rubus ursinus is a species of blackberry or dewberry known by the common names California blackberry, California dewberry, Douglas berry, Pacific blackberry or Pacific dewberry and trailing blackberry. It is native to western North America. This is a wide, spreading shrub or vine-bearing bush with prickly branches that can tip layer to spread vegetatively. Its white flowers may be distinguished from those of other blackberries by their narrow petals. The species is dioeocious, with male and...

Description ⁵

More info for the term: shrub

Trailing blackberry is a low-growing, trailing or climbing, native
evergreen shrub [9,27,55]. This mound-building shrub can grow to 15 or
20 feet (5-6 m) in length [6,13,55]. The densely prickled stems are
greenish when young but turn brown at maturity [9]. The somewhat
prickly, deeply-lobed, alternate leaves are palmate and a lighter green
color beneath [9,13,27].

The stems of most blackberries are biennial. Sterile first-year stems,
known as primocanes, develop from buds at or below the ground surface
and produce only leaves. Lateral branches, or floricanes, develop in
the axils of the primocanes during the second year and bear both leaves
and flowers [24].

Perfect flowers of trailing blackberry develop in clusters of 2 to 15
near the ends of leafy branches [9,13,55]. Fruit is red and hard when
immature but shiny black when ripe [6]. Fruit is oblong or conical,
somewhat bristly, and up to 0.8 inches (2 cm) in length [9,55].
Aggregates of druplets, commonly referred to as "berries," are sweet and
flavorful at maturity [9,27].

Distribution ⁶

Trailing blackberry grows from British Columbia to northern California
and eastward to central Idaho [6,27,36]. It is particularly common from
the Cascades to the Pacific Coast [27]. Trailing blackberry extends
through southern California into Mexico [9,55]. The subspecies
macropetalus occurs from British Columbia and Idaho southward into
northern California [36].

Habitat characteristics ⁷

More info for the terms: fresh, shrubs

The trailing blackberry occurs across a wide range of sites from warm,
open areas to dense woodlands [27,36]. It is particularly common in
prairies, clearings, waste places, and canyons [36,55]. Trailing
blackberry frequently assumes prominence on sites which have been burned
or logged [16,27,36] and on river terraces or gravel bars dominated by
red alder (Alnus rubra) [19].

Soils: Blackberries (Rubus spp.) grow well on a variety of barren,
infertile soils [6]. These shrubs tolerate a wide range of soil texture
and pH but require adequate soil moisture for good growth [10].
Trailing blackberry appears to be tolerant of periodic flooding by
brackish or fresh water [65].

Elevation: Trailing blackberry grows from sea level along the Pacific
Coast to middle elevations farther inland [27,36]. Generalized
elevational ranges for given locations are as follows [9,13]:

< 2,000 feet (610 m) in the Santa Monica Mtns., CA
< 3,000 feet (914 m) in southern California

Fire ecology ⁸

More info for the term: duff

Trailing blackberry is a common invader on recently burned sites in the
Pacific Northwest [16,39,53]. Populations are capable of dramatic and
rapid expansion on disturbed sites [25,66] through sprouting or seedling
establishment [9,16]. Belowground regenerative structures are generally
well protected from the harmful effects of heat and permit rapid
recovery where trailing blackberry plants were present in the preburn
community. Seedbanking is also an important postfire regenerative
strategy [52]. Seeds accumulate in the soil or duff, remaining viable
long after this seral species has been eliminated from mature forest
communities. Seeds commonly germinate in great abundance after fire.
The relatively large, sweet, succulent fruit of blackberries amply
"reward" animal dispersers [40], and some postfire dispersal of seed
from off-site is probable.

National nature serve conservation status ⁹

United States

Sources and Credits

1. (c) Brent Miller, some rights reserved (CC BY-NC-ND), http://www.flickr.com/photos/88016824@N00/3563822238
2. (c) Franco Folini, some rights reserved (CC BY), http://www.flickr.com/photos/livenature/10891447736/
3. (c) Paul Asman and Jill Lenoble, some rights reserved (CC BY), http://www.flickr.com/photos/pauljill/9258931280/
4. Adapted by dlimandri from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Rubus_ursinus
5. Public Domain, http://eol.org/data_objects/24638827
6. Public Domain, http://eol.org/data_objects/24250134
7. Public Domain, http://eol.org/data_objects/24638830
8. Public Domain, http://eol.org/data_objects/24638833
9. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/14679410

More Info

• iNat taxon page
• Biodiversity Heritage Library
• BOLD Systems BIN search
• Calflora
• CalPhotos
• eFloras.org
• Flora of North America (beta)
• Global Biodiversity Information Facility (GBIF)
• HOSTS - a Database of the World's Lepidopteran Hostplants
• IPNI (with links to POWO, WFO, and BHL)
• Jepson eFlora
• NatureServe Explorer 2.0
• OregonFlora.org
• SEINet Symbiota portals
• Tropicos
• USDA PLANTS database
• VASCAN by Canadensys
• World Flora Online

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