Blueblossom
Ceanothus thyrsiflorus
Last reviewed: June 2026
Ceanothus thyrsiflorus (Blueblossom) is an evergreen shrub native to California and Oregon that produces clusters of blue flowers from March through May. This drought-tolerant plant attracts bees, butterflies, and hummingbirds.
Blueblossom (Ceanothus thyrsiflorus) is not on the ASPCA Animal Poison Control Center toxic plant list for dogs or cats (aspca.org (opens in new tab), last reviewed 2026-05-21). If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
full sun
Water
low
Size
72"–240" H × 72"–240" W
Bloom
Mar, Apr, May
Native to
CA, OR
Pollinators
bees, butterflies, hummingbirds
Browse plants for this ecoregion
Blueblossom is a large native shrub or small tree with glossy evergreen leaves and stunning blue flower clusters in spring. It grows quickly to 6-20 feet tall and wide, thriving in full sun with minimal water once established.
Growing Blueblossom
Grow Blueblossom in full sun and low water. Mature plants reach 72 to 240 inches tall and spread 72 to 240 inches wide. Expect moderate maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Blueblossom is an HOA-friendly choice in the right placement. Maintenance level: moderate. Tidiness: 3 out of 5.
Works well in: mid zone, backyard only.
- Can grow quite large if not pruned regularly
- May appear too naturalistic/wild for formal landscapes
- Some cultivars drop blue flower petals that can stain hardscapes
Wildlife value
Host plant for pale swallowtail butterfly, California hairstreak butterfly.
Excellent pollinator plant that attracts native bees, butterflies, and hummingbirds. The dense foliage also provides nesting habitat and shelter for birds.
Common questions
- When does Ceanothus thyrsiflorus bloom?
- Blueblossom typically blooms from March through May, producing dense clusters of small blue flowers.
- What pollinators visit Ceanothus thyrsiflorus?
- Blueblossom attracts bees, butterflies, and hummingbirds with its nectar-rich flowers during the spring blooming period.
- Where is Ceanothus thyrsiflorus native?
- This species is native to California and Oregon, where it grows naturally in coastal and foothill regions.
- How much water does Blueblossom need?
- Once established, Ceanothus thyrsiflorus is drought-tolerant and requires low water, making it well-suited for Mediterranean climates and water-wise gardens.
- Is Blueblossom toxic to dogs?
- Blueblossom is not on the ASPCA Animal Poison Control Center toxic plant list for dogs (aspca.org).
- Is Blueblossom toxic to cats?
- Blueblossom is not on the ASPCA Animal Poison Control Center toxic plant list for cats (aspca.org).
- Is Blueblossom HOA-friendly?
- Blueblossom is generally an HOA-friendly choice in the right placement, with moderate maintenance.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Ready to grow Blueblossom? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Not sure where to start? Take the 2-minute yard quiz