Dahlias: A Bold Bloom

Dahlias should be planted in spring, after the danger of frost has passed. This means planting from mid-April to late May, depending on the climate. The soil temperature should be at least 10°C for successful growth. If you want an earlier start, you can pre-sprout tubers indoors in pots in March or April and transplant them once the weather warms up.

Yes, dahlias are perennials, but they are not winter-hardy in most of Europe (except for very mild regions). In areas with frost, dahlias need to be lifted and stored indoors over winter. In warmer regions (Mediterranean climates), they can be left in the ground with a thick layer of mulch for protection.

Dahlias can be planted in pots from mid-spring (April-May).

If growing in a greenhouse or conservatory, you can plant them earlier (March-April) and move them outside once temperatures remain above 10°C.

Potted dahlias benefit from an early start indoors, leading to earlier flowering.

Dahlias bloom from mid-summer (July) until the first frost (October/November). If started early indoors, some varieties may bloom as early as June. Regular deadheading and feeding help extend the blooming period.

Planting:

1. Choose a sunny location – Dahlias need at least 6-8 hours of direct sunlight daily.
2. Soil preparation – They prefer rich, well-draining soil with compost or organic matter added.
3. Planting depth –
   • Tubers: Plant 10-15 cm deep, with the "eye" facing upwards.
   • Potted dahlias: Ensure good drainage and use a large pot (30-40 cm wide & deep).
4. Watering – Water moderately after planting; increase watering once sprouting begins. Avoid overwatering tubers before they sprout.

Ongoing Care:

• Staking: Tall varieties need support.
• Fertilising: Feed with a low-nitrogen, high-potassium fertiliser every 2-3 weeks.
• Deadheading: Remove spent flowers to encourage continuous blooms.

Yes, but only if protected from frost. In colder climates, move the pots to a frost-free location (5-10°C), such as a garage or greenhouse. If left outside, dahlias will die in freezing temperatures.

Identify spent flowers: Remove faded blooms by cutting down to the first set of full leaves or side shoots.

Use sharp secateurs to make a clean cut.

Avoid cutting seed heads, as they take energy away from new flower production.

Dahlias are mildly toxic to dogs but not highly poisonous. They can cause mild gastrointestinal upset (vomiting, diarrhea, or drooling) if ingested in large amounts. Keep dahlias out of reach of dogs that like to chew on plants.

Yes, dahlias thrive in full sun and need at least 6-8 hours of sunlight per day to bloom well. In very hot climates, they appreciate light afternoon shade to prevent excessive drying.