Agastache 'Blackadder'
giant hyssop 'Blackadder'
One of the hardiest and most reliably perennial of the genus. Its blue-black spikes of paler-lipped flowers darken in late September and provide winter interest. The aromatic leaves suggest anise
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Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Black Blue | Green | ||
| Autumn | Black Blue | Green | ||
| Winter |
Position
- Full sun
Aspect
West–facing or South–facing
Exposure
Sheltered Hardiness
H4Botanical details
- Family
- Lamiaceae
- Native to the UK
- No
- Foliage
- Deciduous
- Habit
- Bushy
- Genus
Agastache are herbaceous perennials with simple, aromatic leaves and small 2-lipped tubular flowers in whorls forming dense spikes, in summer and autumn; some are rather tender but can be grown as annual bedding
- Name status
Accepted
How to grow
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
Propagation
Root semi-ripe cuttings in late summer and overwinter under cover; propagate by division in spring. This cultivar is sterile
Suggested planting locations and garden types
- Cottage and informal garden
- Gravel garden
- Mediterranean climate plants
- Banks and slopes
- Flower borders and beds
Pruning
Trim back stems in late autumn to reduce windrock. Prune flowered stems back in spring
Pests
Generally pest-free
Diseases
Can suffer from powdery mildews
Get involved
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