About
Agastache 'Blackadder' is a robust perennial known for its elongated, aromatic leaves that feature serrated edges. From July through October, it produces tall, upright flower spikes adorned with densely packed, dark violet-purple to dark blue blooms resembling bottlebrushes.
About the genus
Agastache consists of herbaceous perennials featuring straightforward, fragrant foliage and small tubular flowers with two lips, arranged in whorls that create compact spikes during the summer and autumn months. While some species may be somewhat tender, they can also be cultivated as annual bedding plants.
Growing conditions
- Sunlight
- Full sun
- Soil type
- Chalk, Loam, Sand
- Soil pH
- Acid, Alkaline, Neutral
- Soil moisture
- Well-drained
- Aspect
- West-facing, South-facing
- Exposure
- Sheltered
- UK hardiness
- H4
Plant details
- Plant type
- Herbaceous Perennial
- Habit
- Bushy
- Foliage
- Deciduous
- Height
- 0.5-1 metres
- Spread
- 0.1-0.5 metres
- Time to full height
- 2-5 years
- Suggested uses
- Cottage and informal garden, Gravel garden, Mediterranean climate plants
- Fragrance
- Flower
Care notes
- Cultivation
- Grow in well-drained fertile soil in full sun. Excellent drainage is especially important during the winter months. It can suffer during cold wet winters
- Pruning
- Trim back stems in late autumn to reduce windrock. Prune flowered stems back in spring
- Propagation
- Root semi-ripe cuttings in late summer and overwinter under cover; propagate by division in spring. This cultivar is sterile
- Pest resistance
- Generally pest-free
- Disease resistance
- Can suffer from powdery mildews