Dahlia Cav.

Overview

Dahlia belongs to the daisy family, Asteraceae. Kew gives its native range as Mexico to Colombia, and the RHS likewise says dahlias come from Central America and Mexico. They are tender perennials that survive the winter as underground tubers: the top growth dies back and re-sprouts in spring. They will not survive frost and should stay indoors until temperatures are consistently above 5 °C (RHS).

Flora of Iraq notes that the cultivated forms are “legion”: wild forms have red rays, while cultivation offers a wide range of colours. Flora of Tropical East Africa warns that the names of these popular ornamentals are not authoritative, so garden names often do not match botanical species.

Classification and characters

The Spanish botanist Cavanilles published the genus in 1791. Flora of Iraq describes the cultivated dahlia as glabrous or nearly so, mostly up to 1.4 m tall, with bipinnate lower leaves of lanceolate to ovate, toothed leaflets, leafy and more or less reflexed phyllaries, and radiate, somewhat nodding flower heads.

Dahlia coccinea, shown in the plate at the top of this page, and Dahlia pinnata are both accepted by WCVP and native to Mexico; D. coccinea extends south to Guatemala, Belize and El Salvador.

Distribution

WCVP records the genus as native to 14 TDWG botanical regions and introduced in 43 more.

BelizeColombiaCosta RicaEl SalvadorGuatemalaHondurasMexico CentralMexico GulfMexico NortheastMexico NorthwestMexico SoutheastMexico SouthwestNicaraguaPanamá

Introduced

Accepted species

WCVP accepts 43 species; names with × are natural hybrids. The count changes with revisions; checked 2026-10-24.

Historic plates

Plates in date order; the printed names are kept as they appear, current names are on the species pages and the topic page.

• 

  Dahlia coccinea

  Curtis's Botanical Magazine · 762 · 1804
  Sydenham Edwards
• 

  Dahlia bidentifolia

  The Paradisus Londinensis · 1805
  William Hooker
• 

  Dahlia glabrata

  Edwards's Botanical Register · 29 · 1840
  Sarah Anne Drake, G. Barclay

Flower-form groups and cut-flower handling

Gardeners group dahlias by flower form, such as waterlily, pompon and single; RHS Find a Plant marks the group after the cultivar name, for example C for cactus, Bal for ball and Col for collarette. For the best blooms, pinch out the smaller buds behind the large central bud (RHS).

As a cut flower, Floralife advises buying fully open flowers and keeping them at 1–3 °C for only 3–5 days, since longer storage cuts vase life by 20–30%; vase life is 4–10 days and ethylene sensitivity is low. The stems are hollow, counted as “dirty” and hard to hydrate, and wilt easily, so store and ship them in water; give a fresh cut when arranging and change the water with a re-cut every couple of days. They last less long in foam than in a vase, so hydrate them well first. Watch for botrytis and for thrips, which fleck the petals.

Further reading

• Flower guide
• Reference library

References

1. WCVP · World Checklist of Vascular Plants (via ChecklistBank dataset 2232) · accessed 2026-10-24
2. Kew (POWO data on the ColPlanta site) · Dahlia, with notes from Flora of Iraq and Flora of Tropical East Africa
3. RHS · How to grow dahlias
4. Floralife · Dahlia care and handling