California Blackberry

California Blackberry © SBernhard

Pacific Blackberry, Trailing Blackberry
Rubus ursinus
NATIVE

Description (Jepson, PlantID.net)

  • Eudicotyledon
    • Eudicots are a major lineage of flowering plants; see family for general characteristics
  • Rose Family (Rosaceae)
  • Winter-deciduous perennial vine or shrub
  • Stems with many sharp prickles (extensions of the epidermis)
  • Leaves
    • Simple (not divided into leaflets) with 3 lobes or compound with 3 leaflets 
    • Coarsely toothed, with hair on underside
  • Flowers
    • Inflorescence (flower arrangements) is a cyme (branched stem with flowers opening from the top down) of 1 to 5 white to pale-pink flowers
    • Male and female flowers usually on separate plants (dioecious)
      • Female flowers have smaller petals (~ 0.25 in.) and a central cluster of many pistils
      • Male flowers have larger petals (~ 0.5 in.) and a central cluster of many stamens
    • Hypanthium (floral cup formed from the fusion of petals, sepals, and stamens) is flat or saucer-shaped
    • Ovary superior (above the attachment of other flower parts)
  • Berry is actually a collection of dark purple fruits, each one a drupelet (a small fleshy fruit with a hard seed, e.g. raspberry segment)
  • Height to ~6 ft.

Distribution

  • Native to California
    • Grows in scrublands, woodlands, along streams, and in open or disturbed areas
    • See Calflora for statewide observations of this plant
  • Outside California, grows from Canada south to Baja California, Mexico, and east to the Rocky Mountains
  • Grows at elevations to 4,900 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

  • Deer browse the stems and foliage
  • Many animals, including birds, depend on the fruit as a food source
  • Many animals use the dense thickets for nesting sites and protective cover, including bees
  • Larval food source for some butterflies, including western tiger swallowtail (Papilio rutulus), mourning cloak (Nymphalis antiopa), and gray hairstreak (Strymon melinus)
  • Native people had many uses for California blackberry
    • Berries were eaten fresh or dried, sometimes mixed with meat to form pemmican
    • Roots were made into a tea used to treat diarrhea
    • Leaves were also used to brew tea
    • Young shoots could be boiled and eaten
Flower (L), Fruit (M), Prickles (R)
© KKorbholz (L, R), DSchiel (M)

Name Derivation

  • Rubus (ROO-bus) – from the Latin for “bramble” or “blackberry”
  • ursinus (ur-SINE-us) – from the Latin for “bear-like”

Notes

  • Pollinated by native bees
  • Blackberries have prickles, rather than thorns or spines, which help deter herbivory
    • Prickles grow from the outer layers (epidermis) of plant stems, as on roses
    • True thorns are sharp-pointed modified stems, as on citrus trees and at Edgewood on chaparral pea (Pickeringia montana var. montana)
    • Spines are sharp-pointed modified leaves, as on cacti and at Edgewood on gooseberries, or leaf parts, as on leather oaks
  • California blackberry is sometimes considered a “weed” as it can form dense populations along streams and ditches, out-competing other vegetation

ID Tips

  • May be confused with non-native Himalayan blackberry (R. armeniacus) or poison oak (Toxicodendron diversilobum)
    • California blackberry has 3 smaller leaflets, green on both sides, and a round stem with many small straight prickles (a more delicate looking plant!)
    • Himalayan blackberry has 3-5 large leaflets with white undersides and a 5-angled stem with stout, sharp, curved, widely-spaced prickles
    • Poison oak also has leaflets of three, but the leaves are not hairy
    • Mnemonic – “Leaves of three, let it be; If it’s shiny, watch your hiney; If it’s hairy, it’s a berry”
Leaves of California Blackberry (L), Poison Oak (M), Himalayan Blackberry (R) © DSchiel

At Edgewood

  • Found in moist areas and riparian woodlands
  • Flowers April – June
  • Fruits in summer

See General References

Specific References

    Agriculture and Natural Resources, University of California. 2019. Weed Gallery: Wild blackberries–UC. State-wide Integrated Pest Management Program.

      Tirmenstein, D. 1989. Rubus ursinus. Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

        Wilson, B. 2012. Rubus ursinus, Pacific Blackberry in the wild. Las Pilitas Native Plant Nursery.