How to Grow Dahlia Dinnerplate Decora

Dahlia Dinnerplate Decora

Dahlia × hybrida 'Decora'

flower

Dahlia Dinnerplate Decora is a stunning large-flowered dahlia cultivar known for its massive blooms that can reach 10-12 inches in diameter, featuring vibrant colors and fully double petals. These dramatic flowers make exceptional cut flowers and garden focal points, thriving in warm-season gardens. The plants are tall and vigorous, typically reaching 3-4 feet in height.

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Growing Conditions

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Sun: Full sun, 6-8 hours daily (8+ hours ideal for prolific blooming)

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Water: Consistent moisture; water deeply 1-2 inches per week. Keep soil evenly moist but not waterlogged. Reduce watering in fall as tubers prepare for dormancy.

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Spacing: 24 inches

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Days to maturity: 70-90 days from planting to first bloom

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Planting depth: Plant tubers 4-6 inches deep with the 'eye' (growing point) facing upward. Plant after last frost when soil is warm.

Soil

Type: Well-draining loamy soil rich in organic matter

pH: 6.0-7.0

Amendments:

compost aged manure perlite or coarse sand for drainage

Growing Zones

Find your zone →

Zones 6-10; grown as an annual in colder regions or dig tubers for storage

6a 6b 7a 7b 8a 8b 9a 9b 10a 10b

Growth Stages

Sprouting & Early Growth

2-3 weeks

Tubers develop shoots and emerge from soil. Foliage appears, beginning with 2-4 leaves.

Ensure consistent moisture and warmth (60-70°F+). Begin staking or cage support early; dahlias benefit from structural support before they become heavy.

Vegetative Growth

3-4 weeks

Plant rapidly produces leafy stems, reaching 12-24 inches tall. Stems thicken and leaf area expands significantly.

Pinch main stem at 12 inches to encourage branching and more flowers. Provide sturdy support stakes. Fertilize every 2 weeks with balanced fertilizer or one higher in potassium.

Budding & Flowering Begins

2-3 weeks

Terminal buds develop at stem tips. First blooms appear, initially smaller but quickly enlarging. Plant reaches mature height of 3-4 feet.

Deadhead spent blooms to encourage continuous flowering. Pinch side buds if you want exhibition-sized dinnerplate blooms. Maintain consistent water and weekly feeding.

Peak Bloom Period

8-12 weeks

Plant produces massive 10-12 inch fully double flowers in succession. Multiple blooms open simultaneously across the plant.

Harvest flowers early morning for best vase life. Continue deadheading. Monitor for pests and diseases in humid conditions. Maintain consistent watering schedule.

Senescence & Tuber Maturation

4-8 weeks until frost

As temperatures cool in fall, blooming slows. Foliage yellows; underground tubers enlarge and store energy for next season.

Reduce watering gradually. Stop fertilizing by late August. Cut plants back to 4 inches after first frost. Carefully dig tubers, cure them for 1-2 weeks, and store in cool (45-50°F), dry location over winter.

Companion Planting

Plan your garden →

Plant with:

zinnias cosmos salvia coreopsis rudbeckia liatris ornamental grasses lavender

Avoid planting near:

potatoes tomatoes peppers eggplants

Common Pests

Spray foliage with water to increase humidity. Apply miticide or neem oil if severe. Improve air circulation.
Remove affected flowers. Use blue sticky traps. Apply spinosad or neem oil. Avoid over-fertilizing with nitrogen.
and
Hand-pick early morning or evening. Use beer traps or copper barriers. Apply diatomaceous earth around base.
Improve air circulation; avoid overhead watering. Apply sulfur dust or fungicide. Remove heavily infected leaves.
Hand-pick in early morning. Use pheromone traps away from dahlias. Apply neem oil or spinosad.
Plant virus-free tubers. Control aphids which transmit virus. Remove and destroy infected plants.

Uses

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Edible Petals & Tuber

Culinary

Dahlia petals are edible with a slightly sweet, nutty flavor and are used as garnish in fine cuisine. The tubers are edible and were traditionally eaten by Aztec civilizations. [source]

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Cut Flowers & Floral Design

Household

Dinnerplate varieties are prized by florists and garden enthusiasts for their enormous, dramatic blooms that serve as focal flowers in arrangements. They have excellent vase life of 5-8 days. [source]

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Pollinator Attraction

Wildlife

Dahlia flowers attract bees, butterflies, and other pollinators throughout the growing season. The abundant nectar and pollen make them valuable for supporting beneficial insect populations. [source]

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Dried Flowers & Preservation

Craft

Dahlia blooms can be dried for dried flower arrangements and crafts. Hang-dry upside down in a warm, dark location for 2-3 weeks to preserve their color and form. [source]

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Traditional Herbal Use

Medicinal

In traditional Mexican and Asian medicine, dahlia tubers and flowers have been used to support digestive health and manage blood sugar. Modern research continues investigating bioactive compounds. [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 early morning when stems are turgid, using sharp clean scissors. Cut at a 45-degree angle and immediately place in cool water. Dahlia flowers last 5-8 days in a vase. For exhibition, cut side buds to direct energy to main terminal bloom. Dahlias bloom until frost; continue harvesting to extend flowering.

Fun Facts

🌱 Dahlia Dinnerplate Decora blooms are among the largest of all garden flowers, with some exceptional specimens reaching 12-14 inches across—as large as a dinner plate, hence the name.
🌱 Dahlias are native to Mexico and were sacred to the Aztec people, who called them 'acocotli' and used both flowers and tubers as food and in ceremonies.
🌱 The name 'Dahlia' honors 18th-century Swedish botanist Andreas Dahl. The flower was designated the national flower of Mexico in 1963.

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