Anise hyssop (Agastache foeniculum) derives its common name from its licorice-scented foliage and flowers. Anise hyssop also has fragrant undertones of its relative, mint. The flowers of this variety are lavender and attract bees, butterflies and hummingbirds. Anise hyssop thrives in full sun and moderately moist to dry soil that is well drained. Anise hyssop can grow three to six feet high, and it blooms from early summer through mid to late fall.
The 'Blue Fortune' cultivar of hyssop is closely related to the anise hyssop, but its flowers are a lighter shade of blue. 'Blue Fortune' prefers full sun, but it can tolerate wetter, colder climates as well as light shade. It blooms primarily at the height of summer and is very attractive to butterflies. In fact, its peak blooming period coincides with the peak butterfly season in most areas where it grows. 'Blue Fortune' grows very quickly to heights of one to three feet.
Like the anise hyssop, the hyssop cultivar 'Wrinkled Giant' has a strong scent of licorice and mint. Compared with other varieties, it grows slowly and can reach four feet in height. Its flower spikes are lavender-blue to purple and attract bees, hummingbirds and butterflies. This cultivar tolerates humidity and moisture, and it can grow in a range of garden environments, 'Wrinkled Giant' thrives in full sun and well-drained soil, which can be kept wetter than for other varieties of hyssop.
The sunset hyssop (Agastache rupestris), another fast-growing variety, is usually one to three feet tall and does well in drier climates in the American West. It earned its name from the blazing sunset hues of its flowers; oranges, bronze and yellow give way to shades of pink. Its blooming process begins during the early summer and quickly accelerates. The most profuse flowers typically appear in August and can last into the fall. The sunset hyssop prefers full sun but can tolerate some shade. Like other hyssop varieties, it is a favorite of butterflies and hummingbirds.