Agastache, also known as giant hyssop, is a genus of around 30 upright herbaceous perennials, most of which are native to North America.
Agastache hybrids typically have more attractive flowers and a better ability to withstand winter than species plants. The hybrid flowers come in various colors, such as red, orange, pink, yellow, and white. These hybrids usually have dense terminal spikes of small 2-lipped tubular flowers that bloom from mid-summer to fall in many-flowered verticillasters (false whorls) on square stems, typically reaching 2-4' in height. The stems are adorned with opposite pairs of serrated, fragrant (anise/licorice scented) gray-green to medium-green leaves. The flowers are appealing to bees, hummingbirds, and butterflies.
'Blue Fortune' is one variety that showcases tiny, tube-shaped, lavender-blue flowers tightly packed in rounded verticillasters in 4" long interrupt" d terminal spikes on sturdy square stems, usually growing to 3' tall. These flowers bloom freely from summer to early fall and are attractive to butterflies. The ovate-lanceolate leaves (up to 4" long) are down" beneath and have a pleasant minty-anise fragrance. The leaves can be used in potpourris or to flavor cold drinks.
Agastache plants thrive in average, medium moisture, well-drained soils in full sun. They can tolerate some light shade, but good soil drainage is crucial. Agastache plants will struggle and might not survive the winter in hard clay soils that retain moisture. Once established, they can tolerate heat and some dry soils. To encourage additional blooming, it's recommended that it's deadhead-spent flowers. Agastache hybrids typically withstand winter conditions to at least USDA Zone 6. When winter survival is a concern, place them in protected locations (e.g., southern exposures) and leave the leaf and flower stems over winter for added protection. Sandy/gravelly mulches can safeguard the plants and prevent rot. Hybrids grown from seed will not usually produce true offspring.