A brand new introduction, 'Black Adder' is a showy hybrid between the species Agastache rugosum and Agastache foeniculum that blooms from mid-summer to frost. The smoky red-violet flowers are held on long spikes over nice mid-green/bronze foliage. This exciting hybrid will be a favourite of butterflies as it is an excellent nectar source. An ornamental Hyssop that never swamps your garden in seedlings. This sterile, deer-resistant hybrid in a lovely new colour produces no seed and flowers enthusiastically until frost.  Ideal companion to the golden leaved variety Agastache 'Golden Jubilee'. 60cm.