Dahlia coccinea

RHS Plant Profile
scarlet dahlia
Plants for pollinators
Herbaceous Perennial

A variable tuberous perennial, usually 1.2-1.5m high but can reach to 3m high, with branched, brown-purple stems, toothed leaves up to 40cm long, dark green above and paler below. Single flowerheads, 8-10cm across, have golden centres surround by ray florets which are usually bright orange-scarlet but may be yellow, orange, dark maroon or many-coloured, from summer to autumn

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

1-1.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity
2–5 years
Max Spread
0.5-1 metres
Max Height
1-1.5 metres

Growing Conditions

Chalk Loam Sand
Moisture
Moist but well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
East–facing or South–facing or West–facing
Exposure
Sheltered
Hardiness
H3

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Asteraceae
Native to GB/Ireland
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
Correct
Plant Range
Mexico to Guatemala

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, then in mild areas and on well-drained soils leave the tubers in the ground and protect with a deep organic mulch, while in colder areas or on heavy soils lift and store the tubers and replant in late spring after all danger of frost has passed; for more advice, see dahlia cultivation and our video How to plant dahlia tubers and care tips

Propagation

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

Suggested planting locations and garden types

  • Patio and container plants
  • City and courtyard gardens
  • Cottage and informal garden
  • Wildlife gardens
  • Cut flowers
  • Flower borders and beds

Pruning

Deadhead to prolong flowering

Pests

May be 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, Verticillium wilts, and virus diseases