Agastache
Agastache rugosa
by Nancy Miller, Fairfax Master Gardener
Agastache (ag-ah-STA-kee), also known as Giant Hyssop or Hummingbird Mint, is part of the Lamiaceae family of flowering plants that includes mint, deadnettle and sage. There are two subdivisions within the family, one native to North America and one to Asia. The genus has about 22 species of herbaceous perennials, most native to North America, but not to Virginia. The genus name (from ancient Greek) means “very much” and “ear of grain,” which describes the flower spikes. These are tall mints with stout, sharply square stems. As with all mints, plant them where you don’t mind them spreading.
Agastache are showy, fragrant, long-blooming perennials with spikes of flowers ranging from white to blue to shades of red and purple. They have advantages for our area: excellent resistance to deer and rabbits and heat-and-drought tolerance. In addition to being great additions to a pollinator garden, rock garden or naturalized area, they bloom most of the summer. As advantageous as Agastache may sound, remember there are certain soil requirements that you will have to meet to successfully grow it.
They must have well-drained soils; wet winter feet will rot the crown. If necessary, plant in a raised bed or container in full sun. While they have no serious problems, be on the lookout for spider mites, thrips, aphids, whiteflies and slugs so you can deal with them as necessary.
‘Blue Fortune’
There are several varieties you may find of interest. ‘Blue Fortune’ is a hybrid giant hyssop, a cross between A. Foeniculum and A. rugosa. It grows 2 to 3 feet (60 to 90 cm) tall and 1 to 2 feet (30 to 60 cm) wide in full sun/partial shade but does not tolerate heavy clay or poor drainage. Lavender-blue flower spikes are showy and fragrant, lasting from summer through fall. Be sure to deadhead to promote blooming. Crushed foliage has a minty scent. A second interesting variety is Agastache ‘Kudos™ Mandarin’ with fiery coppery orange flowers on an ultra-compact plant.
Anise hyssop (Agastache foeniculum) is native to the upper Midwest and Great Plains. Commonly known as blue giant hyssop or lavender giant hyssop, every part of this plant smells and tastes like anise (i.e., licorice). It self-sows but is a short-lived perennial and is not as aggressive as other mints. Anise grows 2 to 4 feet (60 to 120 cm) high and 1 to 3 feet (30 to 90 cm) wide and is hardy in Zones 4 to 8. It has 3 to 6-inch-long (7 to 15 cm) flower spikes of pale lavender to purple flowers. The leaves have silvery undersides. This is a plant popular with hummingbirds, small bees and syrphid flies. As with the rest of the family, anise hyssop needs full/partial sun and well-drained soil. This plant was used by the Cree, Cheyenne and Ojibwa peoples for fever reduction, treating respiratory conditions and externally on burns.
The yellow giant hyssop or catnip giant hyssop, Agastache nepetoides, and purple giant hyssop or figwort giant hyssop, Agastache scrophulariifolia, are both listed in the Flora Atlases of New York and of the Southeastern United States. They grow six feet (2 m) high in full/partial sun in moderately wet to dry sandy soil, with purple flowers in late summer to fall. These varieties grow naturally in rich woodland sites with dappled shade, woodland borders, meadows, thickets, floodplain edges and upland woods. They require soil disturbance to successfully establish plants. Clear margins must also be regularly maintained to eliminate competitors because they are easily outcompeted by encroaching vegetation. They are known to attract a wide range of bees and butterflies.
Take your pick of these free-flowering perennials and see how many pollinators you can lure to your yard.
References
- Agastache, North Carolina State University Extension
- Agastache, University of Michigan Herbarium
- Anise Hyssop, Maryland Grows, University of Maryland Extension
- Agastache, New York Flora Atlas
- Agastache, Flora of the Southeastern United States