How to Grow Kew Blue
Kew Blue
Ceanothus 'Kew Blue'
shrubKew Blue is a stunning deciduous to semi-evergreen shrub known for its vibrant blue flowers that bloom prolifically in late spring and summer. This compact, mounding variety of California lilac produces delicate clusters of small, powder-blue flowers that attract pollinators. It's a relatively hardy cultivar compared to other Ceanothus varieties, making it more accessible to gardeners in cooler climates.
When should you plant Kew Blue in your zone?
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Example Kew Blue timeline · Pittsburgh, PA (Zone 6b)
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Plant Kew Blue
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Kew Blue
Late summer into fallBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Kew Blue dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives best in zones 7-9, with some success in warmer zone 6 and cooler zone 10 areas
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Get my Kew Blue timeline →Growth Stages
Establishment
First 6-12 monthsYoung shrub with developing root system and sparse foliage
Water regularly but allow soil to dry between waterings. Avoid transplanting. Protect from harsh winter winds in zone 7.
Vegetative Growth
12-24 monthsShrub develops branching structure and fuller foliage; small shoots appear on branches
Light pruning to shape after flowering encourages bushier growth. Do not prune heavily or into old wood.
Pre-flowering
2-4 weeks before bloomFlower buds begin to form at branch tips; plant maintains compact mounding form
Ensure full sun exposure and good air circulation. Reduce watering slightly to encourage blooming.
Flowering
6-10 weeks (late spring through summer)Prolific clusters of powder-blue flowers cover the shrub; extremely showy display
Remove spent flower clusters to encourage extended blooming. Maintain consistent but not excessive moisture.
Post-flowering/Dormancy
Fall through winterFlowering diminishes; foliage may persist or drop depending on climate; shrub enters semi-dormant state
Reduce watering significantly; allow plant to dry out. Prune lightly if needed. Prepare for winter in colder zones.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with water to dislodge; use neem oil or insecticidal soap in severe cases. Ensure adequate air circulation.
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Improve air circulation; avoid overhead watering. Apply sulfur fungicide or potassium bicarbonate spray if needed.
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Ensure excellent drainage; avoid overwatering. Remove affected plant and soil if rot occurs; do not replant Ceanothus in same location.
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Spray undersides of leaves with insecticidal soap or neem oil. Yellow sticky traps can monitor populations.
Uses
Floral garnish
CulinaryThe delicate blue flowers can be used as an edible garnish for desserts and cocktails, adding visual appeal and a subtle, slightly sweet flavor. [source]
Cut flowers and arrangements
CraftThe powder-blue flower clusters are excellent for fresh floral arrangements and dried flower crafts, providing long-lasting color and texture. [source]
Ornamental landscaping
HouseholdKew Blue is primarily valued as a specimen shrub or hedge plant, providing spectacular seasonal color in drought-tolerant gardens and Mediterranean-style landscapes. [source]
Pollinator support
WildlifeThe abundant blue flowers are highly attractive to bees, butterflies, and other pollinators, making Kew Blue an excellent choice for supporting pollinator populations in the garden. [source]
Traditional herbal use
MedicinalHistorically, some Ceanothus species have been used in Native American medicine and herbal traditions for respiratory support and inflammation, though modern evidence is limited. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Kew Blue is an ornamental shrub, not harvested for food or materials. Cut flowers can be harvested for indoor arrangements by snipping stems in early morning when blooms are fresh. For seed collection, allow some flower clusters to mature and dry on the plant; collect when pods turn brown and split naturally.
Fun Facts
- 🌱 Kew Blue was developed at the Royal Botanic Gardens in Kew, London, one of the world's most prestigious botanical institutions, and the cultivar name honors its breeding origin.
- 🌱 California lilacs (Ceanothus) have a unique ability to fix atmospheric nitrogen through a symbiotic relationship with root nodule bacteria, improving soil fertility in their vicinity without fertilizer application.
- 🌱 The powder-blue flowers of Kew Blue are so profuse during peak bloom that the green foliage is often completely hidden beneath the floral display, creating an almost cloud-like appearance in the landscape.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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