PlantSowGrow
How to grow Dahlia (Bishop of Llandaff)
Dahlia
Glowing scarlet single flowers over almost-black foliage from July to the frosts. Bees love the open centres.
At a glance: Sow late April to late May.
When to sow, plant and harvest
Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.
Growing Dahlia (Bishop of Llandaff): what it needs
- Light
- Full sun · 6+ hours a day
- Watering
- Water generously in dry weather once growing
- Soil
- Rich, well-drained soil
- Spacing
- 60 cm
- Height
- 1 m
- In pots
- Grows well in containers
- Feeding
- High-potash liquid feed weekly from midsummer
- Hardiness
- USDA zones 7–11
Step by step
- Late April – late May · 2 weeks after the last spring frost
Plant Outdoors
Plant 10–15 cm deep, 60 cm apart, in rich soil in full sun once frosts are over.
- 14–28 days after “Start Tubers in Pots” · Mid May – late May
Look for Shoots
Shoots should be up. Protect them from slugs — they love young dahlia and gladiolus shoots.
- 14–21 days after “Plant Out” · Late May – early June
Pinch Out Tips (optional)
Pinch out the main tip above the third pair of leaves for a bushier plant with more flowers.
- 7–21 days after “Pinch Out Tips” · Early June – mid June
Stake the Stems
Put in a stout cane or stake and tie stems in as they grow — the flowers are heavy.
- 50–90 days after “Stake the Stems” · Late July – early September
First Flowers — Deadhead Regularly
Cut faded flowers (and flowers for vases) to keep new buds coming. Take a photo for your journal!
Every year
- FebruaryStart Them Off Again
Check stored tubers/corms, discard any soft ones and pot them up (or plant out once frosts are over).
- NovemberLift and Store
After the first frost blackens the leaves, cut stems to 10 cm, lift, dry off upside down, and store in dry compost somewhere frost-free.
