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Blue Blossom Ceanothus thyrsiflorus

Phonetic Spelling
see-a-NO-thus thurs-i-FLO-rus
Description

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:
  • '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', 'Skylark'
Tags:
#hummingbirds#evergreen#showy flowers#shrub#wildlife plant#honey bees#nectar plant#cover plant#slopes#food source wildlife#ornamentals#children's garden#playground plant#edible fruits#bee friendly
 
Cultivars / Varieties:
  • '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', 'Skylark'
Tags:
#hummingbirds#evergreen#showy flowers#shrub#wildlife plant#honey bees#nectar plant#cover plant#slopes#food source wildlife#ornamentals#children's garden#playground plant#edible fruits#bee friendly
  • 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.
  • 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
  • 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:
    5b, 5a, 6b, 6a, 7a, 7b, 8b, 8a, 9b, 9a
  • 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.
  • 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.
  • 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.
  • Bark:
    Surface/Attachment:
    Smooth
  • Stem:
    Stem Is Aromatic:
    No
  • 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