Oso Manzanita
Arctostaphylos osoensis
- Native to:
- United States
John Game (www.wikidata.org)





Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Ericaceae
- Genus:
- Arctostaphylos
- Species:
- Arctostaphylos osoensis
- USDA Symbol:
- AROS
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Shrub
- Height:
- 60 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- High
- Bloom Months:
- feb,mar,apr
- Bloom Colors:
- white, pink
- Ground Cover:
- Yes
- Evergreen Shrub:
- Yes
- Landscaping Shrub:
- Yes
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★☆ Butterfly & moth species supported by this genus (NWF)
- Pollen Specialist Bee Keystone:
- ★★☆☆☆ Native pollen specialist bee species supported by this genus (NWF)
Garden & Ecology Notes
- Wildlife Value:
- bees, birds, small mammals
- Deer Resistant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts vigorously from basal burls after fire. Benefits from periodic burns that reduce competition and open habitat.
Soil Requirements
- Soil Type:
- sandy, well-drained, nutrient-poor soil
- pH:
- 5.5 - 7.0 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- native to coastal chaparral; prefers open, sunny locations
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Scarification:
- Seed coat scarification required before sowing
- Germination Time:
- 30–90 days
- Notes:
- Seeds have hard coats requiring scarification. Cold stratification improves germination rates significantly.
The above propagation data sourced from Claude AI
Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).; then Cold-moist stratification for 60 days.
Source: Claude AI
ORGHPS Germination Guide: Expose to fluctuation outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in the spring. Requires light or the seed is very fine. Surface sow and expose to light. Requires scarification. Nick or rub between sheets of sandpaper. Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard water and any seeds that remain floating. * immerse in boiling water for 20 seconds