Growing Hydrangeas in Pots: Choosing Varieties, Planting and Care
Hydrangeas grow well in pots when the variety, container and compost are chosen with their eventual size and moisture needs in mind. Learn how to plant, water, feed and protect...
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Delphinium ‘Black Knight Group’
Delphinium Black Knight Group
Delphinium ‘Black Knight Group’ is a tall, upright perennial carrying dense summer spikes of semi-double deep blue-purple flowers with almost black centres. Reaching around 1.75m, it gives strong vertical colour at the back of a border and also makes an excellent cut flower. Grow it in fertile, well-drained soil in full sun, with shelter and support for the tall stems.
✅ Deep blue-purple flowers with dramatic dark centres
✅ Tall spikes give strong vertical structure and cut well
⚠️ Harmful if eaten; wear gloves when handling
Plant Details
Flowering Months
Size
- Max Height
- 1.5 m — 2.5 m
- Max Spread
- 0.5 m — 1.0 m
- Growth Habit
- Tall, narrow growth habit with strongly vertical main stems.
Planting Position
- Sunlight Indicates how much direct sunlight the plant needs each day. Full sun means 6+ hours, part shade is filtered or morning sun, and full shade is little to no direct sun.
- Full Sun
- Aspect Aspect refers to the direction the planting spot faces (north, south, east or west). It affects light levels, warmth and exposure.
- South East West
- Exposure Exposure describes how sheltered or exposed a plant’s position is, particularly to wind and weather.
- Sheltered
- Hardiness Hardiness indicates how well a plant tolerates cold conditions outdoors. Higher ratings generally mean greater frost tolerance.
-
(−15 to −10 °C) Cold-hardy
Ideal Soil Conditions
- Soil Type Soil type describes the texture of the soil (clay, sand, loam, chalk). This affects drainage, nutrients and how roots grow.
- Soil Moisture Soil moisture tells you how wet or dry the soil should be for best growth. Match this to your garden conditions for healthier plants.
- Moist but permeable / Free draining
- Soil pH Soil pH measures how acidic or alkaline the soil is. It affects nutrient availability and can impact plant growth.
Plant Uses & Merits
- Uses
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- Patios / Courtyards
- Flower Borders
- Merits
-
- No pruning required
- Good for Cut Flowers
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