How to grow Dahlia in Australia
Plant dahlia tubers in full sun in rich, free-draining soil after the cold has passed, setting a stake in at planting time. Water deeply once growth is up and feed with a potassium-rich fertiliser as buds form.
At a glance
- Difficulty: Intermediate
- Sun: Full sun
- Water: 6 litres a week, watered every 2 days
- Spacing: 60 cm
- Time to harvest: 90 days
- Time to germinate: 14 days
- Soil pH: 6 to 7.5
- Frost tolerance: Frost tender
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| South East Queensland | August to November | |
| Northern Rivers NSW | August to November | |
| Sydney & Coastal NSW | September to November | Plant tubers Sep to Nov once the soil has warmed; they rot in cold wet ground. |
| Melbourne & Victoria | September to November | Plant tubers Sep to Nov once frosts finish in mid September. Lift or mulch heavily in cold inland gardens once frost blackens the tops. |
| Adelaide & SA | September to November | Plant tubers Sep to Nov after frost. Mulch and water deeply through heatwaves; flowers peak in autumn. |
| Perth & WA | August to November | |
| Tasmania | October and November | Plant tubers Oct to Nov after frost. Lift or mulch heavily in cold inland gardens. |
| Canberra & ACT | November | Plant tubers in November after the last frost. Lift or mulch heavily once frost blackens the tops in April. |
| North Queensland | April to August | Grow as a dry season annual. Plant Apr to Aug, enjoy the flowers, then lift the tubers before the wet or they rot. |
| Darwin & Top End | April to July | Grow as a dry season annual. Plant Apr to Jul, then lift the tubers before the build up or they rot in the wet. |
Varieties
- Cafe au Lait
- Bishop of Llandaff
- Pompon Mix
Companion planting
Good companions
Harvest and storage
Harvest tip
Cut flowers when blooms are fully open, as dahlias do not open much more once picked. Regular cutting and deadheading keeps new flowers forming.
Storage
Cut flowers last 5 to 7 days in a vase. Lift tubers in cold climates and store dry in a cool dark place.