How to Grow Canna Lily Roi Humbert
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Canna Lily Roi Humbert
Canna × generalis 'Roi Humbert'
flowerRoi Humbert is a classic hybrid canna lily cultivar prized for its striking deep red flowers and dark bronze-burgundy foliage. This tall, dramatic plant reaches 4-5 feet and produces showy spikes of large red blooms throughout summer and fall. It serves as an excellent accent plant for borders, water gardens, and tropical-style landscapes.
When should you plant Canna Lily Roi Humbert in your zone?
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Example Canna Lily Roi Humbert timeline · Pittsburgh, PA (Zone 6b)
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Plant Canna Lily Roi Humbert
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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First Canna Lily Roi Humbert blooms
Around Jun 16≈ 60 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Canna Lily Roi Humbert dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 7-11; grown as annual in zones 6 and cooler
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Dormancy/Rhizome Establishment
2-4 weeksRhizome is planted in soil. Underground shoots and roots develop.
Keep soil warm (65°F+) and consistently moist. In cooler zones, wait until soil reaches 60-65°F before planting. Protect from frost.
Emergence & Vegetative Growth
3-6 weeksShoots break through soil; distinctive bronze-burgundy leaves unfurl. Plant grows rapidly, producing multiple stems and expanding foliage.
Ensure consistent moisture and warmth. Begin feeding with balanced fertilizer. Mulch lightly to retain moisture. Remove any dead foliage.
Budding
1-2 weeksFlower buds form at the tips of stems as the plant reaches full height (4-5 feet). Dense bronze foliage provides dramatic backdrop.
Continue regular watering and fertilizing. Switch to higher phosphorus fertilizer to encourage blooming. Support tall stems if needed in windy areas.
Flowering
8-12 weeksLarge, vibrant red flowers open in dense spikes. Multiple blooms appear successively from mid-summer through fall. Dark foliage creates striking color contrast.
Deadhead spent flowers to encourage continuous blooming. Maintain consistent moisture and warmth. Keep fertilizing every 2-3 weeks. Watch for pests.
Senescence & Dormancy
Variable, begins with first cool nightsAs temperatures cool, flowering slows and foliage begins to decline. In frost-prone zones, foliage dies back completely after first hard freeze.
In zones 7-8, dig rhizomes after frost kills foliage. Cut back dead growth. Store rhizomes indoors in cool, dry place over winter. In zones 9-11, mulch heavily and allow to overwinter in ground.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick beetles in early morning; use pheromone traps nearby (not directly on plant); apply neem oil or spinosad in severe infestations
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Spray foliage with strong water jet; increase humidity; apply miticide or neem oil if severe
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Remove and destroy rolled leaves containing larvae; apply Bacillus thuringiensis (Bt) spray for severe infestations
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Hand-pick at dusk; use beer traps; apply diatomaceous earth or copper barriers around base; encourage predators
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Spray with insecticidal soap; use rubbing alcohol on heavily infested areas; improve air circulation
Uses
Edible Starch from Rhizomes
CulinaryCanna rhizomes contain starch historically used as food in tropical regions, producing a nutritious flour similar to tapioca. The rhizomes can be boiled or roasted, though this variety is primarily ornamental. [source]
Fresh Cut Flowers
HouseholdRoi Humbert's dramatic red flower spikes last 7-10 days in vases and make striking cut flower arrangements, tropical bouquets, and exhibition displays. [source]
Pollinator Attraction
WildlifeBright red flowers attract hummingbirds, bees, and butterflies to the garden, providing nectar throughout the long blooming season. [source]
Tropical Garden Design
CraftThe bold foliage and vibrant flowers make Roi Humbert essential for creating tropical, exotic, or contemporary garden styles, working beautifully as a focal point or accent plant. [source]
Traditional Herbal Uses
MedicinalIn tropical medicine systems, canna leaves and rhizomes have been used to treat inflammation and skin conditions, though scientific validation 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
Canna lilies are grown for ornamental flowers rather than harvest. Cut flower spikes for fresh arrangements when the first florets on the spike open; they will continue opening over several days indoors. Enjoy blooms in the garden throughout summer and fall. To save rhizomes in cooler zones, dig carefully after the first hard frost (when foliage blackens), cut back stems to 2 inches, and store in cool (50-60°F), dry location with peat moss or sand through winter. Replant in spring when soil warms.
Fun Facts
- 🌱 Roi Humbert was developed in France in 1906 and named after a royal figure, becoming one of the most widely grown canna varieties worldwide for over a century.
- 🌱 The deep burgundy foliage of Roi Humbert gets its color from anthocyanin pigments, the same compounds that make blueberries blue and red wine red.
- 🌱 Canna lilies are not true lilies at all—they're in the Cannaceae family and are more closely related to bananas and ginger, making them true tropical plants despite hardy cultivars.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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