How to Grow Regal Splendour
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Regal Splendour
Dahlia × hybridus 'Regal Splendour'
flowerRegal Splendour is a stunning decorative dahlia cultivar known for its rich, deep burgundy-purple blooms with full, layered petals. This popular garden dahlia produces large flowers on sturdy stems, making it excellent for cutting and floral arrangements. It's a tender perennial typically grown as an annual in temperate climates.
When should you plant Regal Splendour in your zone?
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Example Regal Splendour timeline · Pittsburgh, PA (Zone 6b)
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Plant Regal Splendour
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 Regal Splendour blooms
Around Jun 26≈ 70 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Regal Splendour dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 8-11; can be grown in zones 6-7 with winter tuber storage
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Tuber/Sprouting
2-4 weeks after plantingDahlia tubers are dormant underground, gradually developing shoots as soil warms
Plant after last frost when soil reaches 60°F. Store winter-dug tubers in cool, dry location at 45-50°F. Check tubers occasionally for rot.
Vegetative Growth
4-6 weeksStems and foliage develop rapidly; plant grows 2-4 feet tall with bushy branching
Pinch out central growing tip when plant reaches 12-18 inches to encourage branching. Stake or support stems. Remove lower leaves for air circulation. Fertilize every 2-3 weeks with balanced or bloom-boosting fertilizer.
Budding & Early Flowering
2-3 weeksFlower buds form at branch tips; early blooms appear, often smaller than mature flowers
Continue staking support. Remove side buds around the main terminal bud if larger blooms desired. Deadhead spent flowers to encourage more blooms.
Peak Flowering
4-8 weeks (peaks in late summer/fall)Abundant large, fully-formed burgundy-purple blooms with many layered petals; maximum color saturation
Harvest flowers in early morning when stems are hydrated. Cut at least 6 inches of stem below blooms. Continue deadheading. Maintain consistent watering and weekly feeding.
Late Season/Tuber Formation
Until frost or end of seasonFlowering continues but may slow as days shorten and temperatures cool; energy shifts to tuber development
Stop deadheading to allow plant to set seed/tubers. Reduce fertilizer (especially nitrogen). In cold zones, dig tubers after first light frost. Cut stems back and cure tubers before storage.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray foliage with water to dislodge; use miticide if severe. Improve humidity and air circulation.
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Remove affected flowers promptly. Use insecticidal soap or neem oil. Attract beneficial insects like ladybugs.
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Improve air circulation, reduce overhead watering. Apply sulfur dust or potassium bicarbonate spray. Avoid planting in shade.
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Hand-pick, especially at night. Use beer traps, copper tape, or diatomaceous earth. Encourage ground beetles.
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Ensure excellent drainage, don't overwater. Cure tubers properly before storage at 45-50°F. Remove and destroy infected tubers.
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Trap in rolled newspaper or straw tubes placed near plants. Remove and destroy nightly. Reduce garden debris.
Uses
Ornamental garnish
CulinaryRegal Splendour dahlia petals are edible and can garnish salads, desserts, and cocktails, adding elegant visual appeal and a slightly earthy, slightly sweet flavor. [source]
Cut flowers & floral arrangements
CraftThese stunning deep burgundy blooms are prized by florists and home arrangers for their large size, full form, and exceptional vase life. Ideal for weddings, events, and fresh bouquets. [source]
Garden ornament & landscape focal point
HouseholdRegal Splendour's dramatic deep purple-burgundy color makes it a striking focal point in garden beds and borders, creating rich color contrast with lighter plants. [source]
Pollinator attraction
WildlifeDahlia blooms attract bees, butterflies, and other pollinators throughout the growing season, supporting local pollinator populations and biodiversity. [source]
Traditional herbal use
MedicinalIn some traditional medicine systems, dahlia tubers and flowers have been used to support digestive health and general wellness, though modern 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 stems are fully hydrated for maximum vase life (7-10 days). Cut at least 6-8 inches below the bloom, leaving foliage on the plant. Remove lower petals and re-cut stems at 45-degree angle under running water. Place immediately in cool water with floral preservative. For tuber harvesting: Dig after first light frost (not hard freeze) in cold zones. Gently remove soil, cure tubers in a cool, dry, airy location for 1-2 weeks, then store at 45-50°F in peat moss, sawdust, or sand.
Fun Facts
- 🌱 Dahlias are native to Mexico and have been cultivated by indigenous peoples for over 2,000 years; they were brought to Europe in the 16th century where they became wildly popular among Victorian gardeners.
- 🌱 Regal Splendour and other dahlias are technically perennials, but in cold climates they must be dug up and stored indoors over winter like tender bulbs, making them behave as annuals.
- 🌱 A single dahlia plant can produce hundreds of flowers over a season if deadheaded regularly, making them exceptionally prolific cut flowers for home gardeners.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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