Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Moist but well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Red Yellow | Green | ||
| Autumn | Red Yellow | Green | ||
| Winter |
Position
- Full sun
Aspect
South–facing or East–facing or West–facing
Exposure
Sheltered Hardiness
H3Botanical 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
Accepted
- Horticultural Group
- Cactus dahlias have fully double blooms, the florets are usually pointed, narrow and revolute for 65% or more of their length and either straight or incurving
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
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
- Cottage and informal garden
- Patio and container plants
- City and courtyard 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 affected by 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
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.