PlantSowGrow
How to plant and care for Delphinium (Pacific Giant)
Delphinium elatum
🌸 Flower
🔁 Perennial
Towering spires of true-blue, purple and white flowers in early summer — the queen of the cottage border.
When to plant and care for it
JanFebMarAprMayJunJulAugSepOctNovDec
Flowers
Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.
Growing Delphinium (Pacific Giant): what it needs
- Light
- Full sun · 6+ hours a day
- Watering
- Water well until established, then in dry spells
- Soil
- Rich, moist, well-drained soil
- Spacing
- 60 cm
- Height
- 1.5–1.8 m
- In pots
- Only in large containers
- Feeding
- General feed in spring
- Hardiness
- USDA zones 3–7
Step by step
- On planting day
Plant
Plant at the same depth as it was in its pot, 60 cm apart, and firm in.
- 0–1 days after “Plant”
Water In Well
Give a full can of water, then keep moist for the first few weeks while roots establish.
- 7–14 days after “Water In Well”
Mulch Around the Base
Spread 5 cm of compost or bark around the plant, keeping it off the stems.
Every year
- MarchGuard Against Slugs
Slugs devour the new shoots — protect them with wool pellets, grit or a beer trap.
- MayStake the Spikes
Put in tall canes and tie the stems loosely every 30 cm — they snap in wind.
- JuneIn Flower
Spires in full flower — take a photo.
- JulyCut Back for a Second Flush
Cut flowered spikes to the ground and feed; smaller spikes often follow in late summer.
