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Herbaceous Perennial

Dahlia Happy Single Romeo ('HS Romeo'PBR) (Happy Single Series) (Sin)
  • RHS Plants for pollinators

dahlia [Happy Single Romeo]

A tuberous-rooted perennial to about 60cm with almost black foliage. Flowers, in late summer and autumn, have a single row of rich red petals with an open, yellow centre

Synonyms
Dahlia 'HS Romeo'PBR
Dahlia 'Romeo'

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Size
Ultimate height
0.5–1 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Chalk
Clay
Loam
Sand
Moisture
Moist but well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Black
Summer Red Black
Autumn Red Black
Winter
Position
  • Full sun
Aspect

South–facing or West–facing

Exposure
Sheltered
Hardiness
H3
Botanical details
Family
Asteraceae
Native to the UK
No
Foliage
Deciduous
Habit
Clump forming
Genus

Dahlia are tuberous rooted perennials with pinnately divided leaves and showy flowerheads, double in many cultivars, in summer and autumn

Name status

Trade

Horticultural Group
Single-flowered dahlias have flowerheads usually less than 10cm across, with one or two rows of spreading ray florets, surrounding a central boss of small tubular disc florets which are valuable for bees and butterflies

How to grow

Cultivation

Plant tubers 10-15cm deep in fertile, humus-rich, well-drained soil, in full sun. Cut back to near ground level in mid-autumn. In mild areas, and on well-drained soils, leave the tubers in the ground and protect with a deep organic mulch. In colder areas, or on heavy soils, lift and store the tubers and replant in late spring after all danger of frost has passed. See dahlia cultivation

Propagation

Propagate by basal softwood cuttings taken in spring from shoots from stored tubers, or divide clumps of tubers ensuring that each division has a viable bud

Suggested planting locations and garden types
  • City and courtyard gardens
  • Cottage and informal garden
  • Patio and container plants
  • Wildlife gardens
  • Cut flowers
  • Flower borders and beds
  • Bedding
Pruning

Deadhead to prolong flowers

Pests

May susceptible to aphids, capsid bug, earwigs, caterpillars, slugs, glasshouse red spider mite and onion thrips

Diseases

May be susceptible to powdery mildews, Dahlia mosaic virus, cucumber mosaic virus, tomato spotted wilt virus, storage rots, leafy gall, crown gall, dahlia smut, grey moulds, fungal leaf spot, Phytophthora, Sclerotinia and Verticillium wilts

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