Giant Hyssop 'Blackadder'

Agastache 'Blackadder' is a top-performing herbaceous perennial that has become a staple of contemporary UK garden design. It is prized for its long-lasting, bottle-brush flower spikes which appear from mid-summer through to autumn. The flowers are a deep violet-blue, emerging from dark, almost black buds, providing a rich colour contrast. The aromatic foliage has a distinct liquorice or aniseed scent when brushed against. Growing to about 90cm tall, it has a tidy, upright habit that works well in the middle of a border. It is a magnet for bees, butterflies, and other pollinators, making it an essential addition to wildlife-friendly gardens. While moderately hardy (H4), it requires a sunny spot with very well-drained soil to survive wet British winters; it often suffers more from winter damp than cold. Cutting the stems back in spring rather than autumn can provide some extra protection to the crown. It is a stunning companion for ornamental grasses.

Sun: Full sun.

Soil: Well-drained soil.

Hardiness: H4 — down to −10°C.

Flowering: Jul, Aug, Sep.