woodland shrub
Blueblossom
Ceanothus thyrsiflorus
1 of 2Native to California and Oregon
Outer California Coast Ranges, north to Oregon
- Light Partial shade Sun tolerance
- Moisture Moisture preference
- Zones 7–11 Cold to heat range
- Bloom Mar–Jun Flowering time
- Height up to 20 ft to 6.1 m
- Life cycle Perennial Annual to perennial
In the garden
A woodland shrub for partial shade. At up to 20 ft, it needs room in shade gardens and woodland edges. Hardy in USDA zones 7–11.
Growing conditions
Light
Full sun Partial shade Full shade
Moisture
Dry Moist Wet
Hardiness zones
Find your zone:
Pollinators & wildlife
- Bees Yellow-faced Bumble Bee
also Western Honey Bee, Black-tailed Bumble Bee, Fuzzy-Horned Bumble Bee +3 more
Buff-tailed Bumble Bee, Habropoda depressa, Horse-fly Carpenter Bee - Flower flies Oblique Streaktail
also Thick-legged Hover Fly, Eurasian Drone Fly, Western Aphideater +5 more
Yellow-shouldered Drone Fly, Black-margined Flower Fly, Common Grass Skimmer, Common Lagoon Fly, Bumblebee Catkin Fly - Butterflies Monarch
also Painted Lady, Variable Checkerspot, Echo Azure +2 more
Lotus Hairstreak, Muir's Hairstreak - Also visited by
- Wasps: Western Yellowjacket, Ancistrocerus bustamente
- Beetles: Seven-spotted Lady Beetle, Twenty-spotted Lady Beetle
- Moths: Orgyia mixta
Butterflies that use this plant
Documented host and nectar records. Each links to a planting guide for that butterfly.
- Hedgerow hairstreakcaterpillar host
- Pale swallowtailcaterpillar host
- Summer azurecaterpillar host
- Monarch butterflynectar
- Painted ladynectar
Full plant details
Where it grows
- Habitat
- WoodlandThe wild plant community it grows in.
- Native range
- California and OregonUnited States (2): CA, OR. Where it grows wild on its own, by state and province.
- Native distribution
- Outer California Coast Ranges, north to OregonThe same native range, usually more exact than the state list, and often noting where it has spread beyond it.
Growing conditions
- Light
- Partial shadeHow much sun it takes, from full sun to full shade.
- Hardiness zones
- USDA 7–11 · Canadian 8–9The cold-to-heat climate range it survives.
- Soil
- Fairly dry, well-drained soilThe soils it grows in naturally.
- Soil texture
- Light to medium (sandy to loamy)The soil grade it prefers, from sand to clay.
- Soil pH
- Mildly acid to mildly alkalineThe acidity to alkalinity it tolerates (7 is neutral).
Growth & form
- Height
- up to 20 ft (to 6.1 m)Typical mature height.
- Spread
- ~15 ft (4.5 m)How wide one plant gets, a guide to spacing.
- Life cycle
- PerennialWhether it lives a single season (annual), two (biennial), or returns for years (perennial).
- Growth rate
- ModerateA relative ranking versus other plants of the same type (USDA), not an absolute rate.
Flowers, foliage & fruit
- Type
- ShrubWhat kind of plant it is.
- Bloom
- Mar–JunWhen it flowers.
- Flower color
- White, BlueThe bloom color, or colors.
- Toxicity
- None knownWhether any part is poisonous to people or pets.