Frangula purshiana
Common name: 
Cascara Buckthorn
FRANG-gew-la PURSH-i-an-a
Rhamnus purshiana
Rhamnus purshianus
Native to (or naturalized in) Oregon: 
  • Deciduous tree to 50 ft (15 m) tall, or an erect shrub 15 ft (4.5 m) tall; twigs soft and velvety pubescent at first; buds naked (without scales), 13 mm long, in 2-3 exposed segments, with rusty pubescence.  Leaves alternate, simple, elliptic to oblong or ovate, 5-15 cm long, flat, round base, abruptly pointed apex, 10-15 conspicuous parallel veins, sparsely serrate or entire, dark green above, lighter below; fall color depending upon sun exposure and varies from pure yellow (shade)to yellow mixed with orange, red, and purple.  Flowers small, green-white, sepals, petals, and stamens in 5s, in clusters.  Fruit 8 mm diameter, purplish-black, sickly sweet taste.
  • Sun or shade.  Best in moist, well-drained soils.
  • Hardy to USDA Zone 3b     Native range from British Columbia south on the west side of the Cascade Mountains to lower California, east through Idaho to western Montana.  The cured bark is used as a mild laxative.
  • Long classified as in the genus Rhamnus, hence Rhamnus purshiana, but now considered in the genus Frangula, therefore Frangula purshiana. See Frangula
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  • plant habit, summer and fall

    plant habit, summer and fall

  • flowers, spring

    flowers, spring

  • leaves and immature fruit

    leaves and immature fruit

  • leaves and fruit

    leaves and fruit

  • shoot, leaves, fruit, bud

    shoot, leaves, fruit, bud

  • leaves, fall

    leaves, fall

  • trunk, bark

    trunk, bark

  • winter twigs and buds

    winter twigs and buds