Little Adder Hyssop

Agastache rugosa ‘Little Adder’ is a compact, upright perennial with aromatic foliage and dense violet-blue flower spikes. Darwin Perennials describes it as shorter and more freely branched than ‘Black Adder’ and ‘Blue Fortune,’ making it useful near the front of sunny mixed borders and in containers. RHS notes that the purple-blue flower spikes continue through summer into autumn. ## Garden Character The dark green leaves are scented, while the whorled flowers draw bees, butterflies, and hummingbirds. The Royal Horticultural Society reports flowering through summer and autumn; local timing varies with climate. Allow about 15–18 inches of height and 18–22 inches of spread, consistent with both the breeder’s figures and RHS’s approximately 45 cm profile. ## Growing Conditions Give it full sun and well-drained soil; it can also tolerate some partial shade. The breeder lists USDA zones 5a–9b. Avoid persistently wet soil, which can encourage root and crown problems in Agastache. The cultivar was bred by Darwin Perennials and received U.S. plant patent PP26,514 on March 15, 2016; that date records issuance, not a statement about current legal status. See the [Darwin Perennials product profile](https://www.darwinperennials.com/Products/Details/?phid=001701774031443), [RHS plant profile](https://www.rhs.org.uk/plants/350001/agastache-rugosa-little-adder/details), and [Brookgreen Gardens record](https://www.brookgreen.org/plant-collection/name/agastache-rugosa-little-adder). ## Maintenance Remove faded flower spikes during the season if a tidier appearance or continued flowering is desired. Cut back old stems as new growth resumes; leave the plant undisturbed through winter where that helps protect the crown.