Dahlias are cold-sensitive and should not be planted until the soil has warmed to above 15°C and all danger of frost has passed.
- Select a sunny garden spot, dahlias require full sun (at least 8 hours daily) to thrive and bloom abundantly, with freely draining soil.
- To plant, dig a hole 10 to 15 cm deep and place the tuber on its side, with the growing eye facing up and refill the hole with soil. Allow at least 30 to 46 cm of space between plants.
- Dahlias require consistent water throughout the growing season. However, they should not be watered until you see the first green shoots poking through the ground; overwatering before shoots are visible can lead to tuber rot.
- After plants reach 30 cm tall, give a hard pinch by snipping out 7 to 10 cm of the growing center to encourage low basal branching, which increases flower production and overall stem length.
- By mid-summer, you may need to stake tall plants to keep them from falling over.
- Dead-heading spent blooms will encourage continuous flowering throughout the season.