Cascara Buckthorn
Frangula purshiana
- Native to:
- Canada, Mexico, United States
iNaturalist: © robirwin (iNaturalist #195009609)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Rhamnaceae
- Genus:
- Frangula
- Species:
- Frangula purshiana
- USDA Symbol:
- FRPU7
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Shrub , Tree
- Height:
- 1000 cm
- Light Requirements:
- Shade
- Drought Tolerance:
- Low
- Bloom Months:
- apr,may,jun
- Bloom Colors:
- yellow, green
- Landscaping Shrub:
- Yes
Wildlife Benefits
- Caterpillars:
- ★★☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Host Plant for Caterpillars
Ceanothus Silkmoth (Hyalophora euryalus), Dimorphic Euchlaena Moth (Euchlaena mollisaria), Elegant Sheep Moth (Hemileuca eglanterina), Eupithecia columbiata, Eupithecia misturata, Johnson's euchlaena moth (Euchlaena johnsonaria), Kaslo silkmoth (Hyalophora "kasloensis"), Sorhagenia nimbosa, Synaxis cervinaria, Western tent caterpillar (Malacosoma californica), Western tussock moth (Orgyia vetusta)
Reported Fauna Sightings
Moths:Sorhagenia nimbosus
Garden & Ecology Notes
- Wildlife Value:
- birds, small mammals
- Fall Color:
- yellow
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts vigorously from the root crown following fire. Common in post-fire succession in Pacific Northwest forests.
Soil Requirements
- Soil Type:
- rich, well-drained loamy soil
- pH:
- 5.0 - 7.0 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- consistently moist
- Notes:
- native to mixed coniferous forests
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 60–90 days
- Germination Time:
- 14–60 days
- Notes:
- Seeds require cold stratification. Fresh seed germinates more readily than stored seed.
The above propagation data sourced from Claude AI
Pre-treatment: Seeds are placed in cold moist stratification for 140 days.
Establishment: R. purshiana is found from British Columbia to California and east into Idaho and western Montana.
Source: npn.rngr.net