How to Grow Dunnett's Dark Crimson Dahlia
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Dunnett's Dark Crimson Dahlia
Dahlia × hybridus 'Dunnett's Dark Crimson'
flowerDunnett's Dark Crimson is a classic decorative dahlia cultivar prized for its rich, deep crimson flowers and reliable performance in garden settings. This medium-height dahlia produces stunning blooms on sturdy stems ideal for cutting and displays. It is a tender perennial typically grown as an annual in most climates.
When should you plant Dunnett's Dark Crimson Dahlia in your zone?
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Example Dunnett's Dark Crimson Dahlia timeline · Pittsburgh, PA (Zone 6b)
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Plant Dunnett's Dark Crimson Dahlia
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 Dunnett's Dark Crimson Dahlia blooms
Around Jun 26≈ 70 days after planting
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Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 8-11; grown as annual in cooler zones
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Tuber Dormancy & Sprouting
Variable; plant after last spring frost dateDahlia tubers remain dormant over winter in storage or ground; shoots begin emerging in spring when soil warms to 60°F+
Store tubers in cool, dry location over winter; inspect for rot before spring planting; divide tubers ensuring each piece has at least one 'eye' (growth bud)
Vegetative Growth
4-6 weeksYoung plant develops compound leaves and branching stem structure; rapid height gain; no flowers yet
Pinch out the main central stem when plant reaches 12 inches tall to encourage bushiness; stake or support growing stems; maintain consistent moisture; apply mulch to retain water and regulate soil temperature
Budding & Early Flowering
2-3 weeksFlower buds appear at branch tips; first blooms open in rich deep crimson colors
Remove side buds if large exhibition flowers desired; fertilize every 2-3 weeks with balanced or phosphorus-rich formula; deadhead spent blooms to encourage more flowering
Peak Flowering
8-12 weeks or until first frostAbundant deep crimson decorative blooms with full double petals; flowers 4-6 inches across; continuous production throughout season
Deadhead regularly; monitor for pests and diseases; maintain consistent watering; provide cut flowers frequently to stimulate more blooms; watch for spider mites in hot, dry conditions
Late Season & Decline
4-8 weeks until frostFlowering slows as temperatures cool and day length shortens; foliage may show yellowing; tubers enlarge underground in preparation for dormancy
Cease fertilizing 4-6 weeks before first expected frost; gradually reduce watering; cut back plant after first killing frost; carefully dig and cure tubers for winter storage in zones below 8
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Increase humidity with overhead watering; use miticides if severe; remove heavily infested leaves; encourage natural predators like ladybugs
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Hand-pick beetles in early morning; use neem oil spray; remove and destroy affected leaves; encourage beneficial insects
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Spray with insecticidal soap or neem oil; remove infested flowers; provide adequate air circulation
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and
Remove debris and mulch near base; use beer traps; handpick at dawn/dusk; apply copper barriers or diatomaceous earth
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Improve air circulation; avoid overhead watering; apply sulfur dust or neem oil spray; remove affected leaves; thin plant if crowded
Uses
Edible Flowers
CulinaryDahlia petals are edible with a slightly sweet, earthy flavor and can garnish salads, desserts, and cocktails for visual appeal and subtle flavor. [source]
Cut Flower Arrangements
HouseholdThe rich crimson blooms are prized by florists and home gardeners for stunning arrangements, bouquets, and floral displays that last over a week in water. [source]
Dried Flower Crafts
CraftPetals can be dried and used in potpourri, pressed flower art, or crafting projects; the deep color is retained reasonably well during drying. [source]
Pollinator Support
WildlifeDahlias attract bees, butterflies, and other pollinators, providing nectar and pollen sources throughout the growing season to support beneficial insects. [source]
Traditional Herbal Use
MedicinalIn traditional medicine, dahlia tubers and roots have been used in some cultures for their potential anti-inflammatory and antioxidant properties, though scientific 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
Cut flowers in early morning when fully hydrated; cut stems at an angle 2-3 inches below flower head; remove lower foliage; place immediately in cool water with floral preservative; flowers last 7-10 days in a vase. Harvest continuously to encourage more blooming. For tuber harvest in cool zones, wait until first frost blackens foliage, then carefully dig 12 inches around plant; brush off soil gently, cure tubers in cool (50-60°F), dark, well-ventilated space for 1-2 weeks before storage.
Fun Facts
- 🌱 Dahlias are native to Mexico and were cultivated by the Aztecs for food (tubers) and ceremonial purposes before being brought to Europe in the 16th century.
- 🌱 The 'Dunnett's Dark Crimson' cultivar is named after its breeder and is celebrated as a reliable heritage variety that has remained popular since its introduction in the early 20th century.
- 🌱 Dahlias have one of the widest flower form variations of any ornamental plant, ranging from simple single petals to fully double blooms with hundreds of layered petals, with 'Dunnett's Dark Crimson' being a classic decorative type.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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