Blue Blossom Ceanothus thyrsiflorus
Other Common Name(s):
- Phonetic Spelling
- see-a-NOH-thus thur-si-FLOH-rus
- Description
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Blue blossom is an easy to grow broad leaf evergreen shrub in the buckthorn (Rhamnaceae) family that, left to its own devices, will grow to a large, tree-like 20 feet high and wide. However, it has a short trunk and spreading branches that can be controlled to spread to a few feet tall. In natural settings, it is ofen found on wooded slopes and canyons, in the neighbourhood of streams, and in evergreen forests of California and Oregon. Blue blossom has truly blue flowers which all gardeners know can be incredibly difficult to find. It can be used for screen and background plantings in large spaces and on slopes.
This shrub is very low maintenance and can be used for a ground cover and for erosion control. The evergreen leaves stay put and the blue flowers fall off individually and are easily blown away by the slightest wind. The densly packed foliage provides excellent cover for songbirds. The genus name comes from keanothos, an ancient Greek name relating to some plants in the buckthorn family. The specific epithet thyrsiflorus means "flowers arranged in a thyrse", in reference to the shape of the infloresence ( thyrsus is the name of the staff, adorned with leaves and berries, that belonged to Bacchus, the Greek god of wine).
Blue blossom is a hardy plant, but it dislikes root disturbance and it should be planted in its permanent site. It is a fast-growing plant that flowers when young. It dislikes heavy pruning and it is best not to cut out any wood thicker than a pencil. Keep in mind when pruning that the plant flowers on the previous year's growth and any pruning is best done immediately after flowering. Constant pruning to keep Blue blossom small can shorten its life.
Diseases, Insect Pests, and Other Plant Problems:
No known diseases or insect pests. May freeze with colder winters. Elk and deer will browse the foliage.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- 'El Dorado'
Upright shrub to 8 feet. Leaves variegated, irregular, with a yellow margin and green center. - 'Skylark'
Compact (5 x 7 foot) and dome-shaped. Long, showy, floral display that blooms late in Spring into Summer.
- 'El Dorado'
- 'El Dorado', 'Skylark'
- Tags:
- Cultivars / Varieties:
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- 'El Dorado'
Upright shrub to 8 feet. Leaves variegated, irregular, with a yellow margin and green center. - 'Skylark'
Compact (5 x 7 foot) and dome-shaped. Long, showy, floral display that blooms late in Spring into Summer.
- 'El Dorado'
- 'El Dorado', 'Skylark'
- Tags:
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Attributes:
- Genus:
- Ceanothus
- Species:
- thyrsiflorus
- Family:
- Rhamnaceae
- Uses (Ethnobotany):
- When crushed and mixed with water, the plant produces an effective and gentle soap. Also used for ceremonial wreaths by Native Americans.
- Life Cycle:
- Perennial
- Recommended Propagation Strategy:
- Seed
- Stem Cutting
- Country Or Region Of Origin:
- Southwestern North America
- Distribution:
- Oregon to Mexico
- Wildlife Value:
- The flowers attract hummingbirds, honey and bumble bees and butterflies. Seeds are a food source for birds and small mammals.
- Play Value:
- Attractive Flowers
- Attracts Pollinators
- Buffer
- Edible fruit
- Wildlife Food Source
- Wind Break
- Dimensions:
- Height: 4 ft. 0 in. - 14 ft. 0 in.
- Width: 5 ft. 0 in. - 14 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Shrub
- Woody Plant Leaf Characteristics:
- Broadleaf Evergreen
- Habit/Form:
- Dense
- Irregular
- Prostrate
- Rounded
- Spreading
- Growth Rate:
- Rapid
- Maintenance:
- Low
- Texture:
- Fine
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Loam (Silt)
- Sand
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- Available Space To Plant:
- 6-feet-12 feet
- USDA Plant Hardiness Zone:
- 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
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Fruit:
- Fruit Color:
- Brown/Copper
- Purple/Lavender
- Fruit Value To Gardener:
- Edible
- Display/Harvest Time:
- Fall
- Fruit Type:
- Capsule
- Fruit Length:
- < 1 inch
- Fruit Description:
- Seeds ripen from August to October. Fruit is small, glandular-sticky, slightly lobed.
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Flowers:
- Flower Color:
- Blue
- Purple/Lavender
- White
- Flower Inflorescence:
- Spike
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Spring
- Flower Size:
- 1-3 inches
- Flower Description:
- Blossoms from mid-May to mid-June with spike-like clusters of blue flowers. Just before buds open they are pinky-lavender.
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Leaves:
- Woody Plant Leaf Characteristics:
- Broadleaf Evergreen
- Leaf Color:
- Green
- Leaf Feel:
- Glossy
- Leaf Value To Gardener:
- Long-lasting
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Leaf Shape:
- Elliptical
- Ovate
- Leaf Margin:
- Serrate
- Hairs Present:
- No
- Leaf Length:
- 3-6 inches
- Leaf Width:
- < 1 inch
- Leaf Description:
- The elliptic to ovate leaves have finely serrated margins and can reach 1.5 inches long and 0.5 inches wide. Three prominent veins on the underside, tip obtuse to acute, margin sometimes gland-toothed.
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Bark:
- Surface/Attachment:
- Smooth
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Stem:
- Stem Is Aromatic:
- No
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Landscape:
- Landscape Location:
- Recreational Play Area
- Landscape Theme:
- Butterfly Garden
- Children's Garden
- Edible Garden
- Design Feature:
- Barrier
- Border
- Hedge
- Attracts:
- Butterflies
- Hummingbirds
- Small Mammals
- Songbirds
- Resistance To Challenges:
- Salt