Delphinium elatum ‘Guardian Blue’

Description

Delphinium elatum ‘Guardian Blue’ is an elegant perennial featuring a low mound of deeply-cut green leaves topped with tall spikes of double, satiny, deep blue flowers. With a height of 1m and a spread of 80cm, it thrives in full sun, well-drained fertile soil, and attracts bees from May to July. Perfect for the back of a sunny border, this hardy perennial adds stunning vertical interest to any garden.

PLANTING and AFTERCARE GUIDE

Best Planting Time

• Spring: Plant Delphinium elatum ‘Guardian Blue’ in early spring once the soil has started to warm. This timing helps roots establish before flowering.
• Autumn: Alternatively, early autumn planting allows the plant to settle in before dormancy, promoting strong growth the following season.

Site Selection

• Sunlight: Choose a location with full sun for maximum flower production. Delphinium elatum ‘Guardian Blue’ performs best in at least 6 hours of direct sunlight daily.
• Soil: Ensure well-drained, fertile soil. Avoid waterlogged conditions, as they can cause root rot. Mix in organic matter such as compost to improve fertility and drainage.

Planting Instructions

1. Prepare the Hole: Dig a hole twice the width and the same depth as the root ball. This ensures adequate space for the roots of Delphinium elatum ‘Guardian Blue’ to spread.
2. Soil Preparation: Blend compost or organic matter into the soil to enrich nutrients and promote strong growth.
3. Planting: Position the plant so the top of the root ball is level with the surrounding soil. Gently backfill and firm the soil to remove air pockets.
4. Watering After Planting: Water thoroughly to help roots settle. Ensure good drainage to prevent waterlogging.

Watering Requirements

• Growing Season: Once established, Delphinium elatum ‘Guardian Blue’ requires moderate watering. Keep the soil moist but allow slight drying between watering sessions.
• Dormant Season: Reduce watering significantly. Only water if the soil becomes excessively dry, as minimal moisture is needed during dormancy.

Feeding

• Spring: Apply a balanced fertiliser in early spring to support new growth and robust flowering.
• Mid-Summer: Light feeding encourages continued blooming and maintains plant vigour throughout the flowering season.

Pruning

• Deadheading: Remove spent flowers to extend bloom duration, maintain a tidy appearance, and stimulate new flower growth.
• Autumn Pruning: After the last blooms, cut the plant back to ground level. This prepares Delphinium elatum ‘Guardian Blue’ for winter dormancy and promotes healthier growth in the next season.

Mulching

• Spring: Apply a 5–7cm layer of organic mulch around the base to retain soil moisture, suppress weeds, and regulate soil temperature.
• Winter: Mulch helps protect roots from frost and prevents soil heaving, ensuring the plant survives the colder months.

Supporting the Plant

• Staking: Due to its tall flower spikes, Delphinium elatum ‘Guardian Blue’ may need staking in windy locations to prevent stems from bending or breaking.

Final Tips

Delphinium elatum ‘Guardian Blue’ is a striking, low-maintenance perennial that brightens any border. By planting in full sun with well-drained, fertile soil, and following these care instructions, you’ll enjoy vibrant blue blooms that attract bees and add dramatic height from May through July.

RHS Details

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