Agastache — Hummingbird Mint / Hyssop
One of the most colorful perennials in the summer and fall garden, Agastache (ah-gah-STAH–key) is a member of the mint family (Lamiaceae) from which most species derive their common name, hummingbird mint.
Green to greenish gray leaves and stiff upright stalks grow in slowly expanding clumps highlighted by spikes of tubular, two-lipped blossoms in white, mauve, lavender, peach, pink, or orange. Flowers are rich in nectar that attracts butterflies, hummingbirds, and bees. Blooming usually lasts until the first hard frost.
Agastache prefers soils low in fertility, somewhat on the alkaline side of the pH scale. If lavender grows well for you, so will agastache. Good drainage in the garden is a must as is a sunny spot that receives deep, infrequent waterings after plants are established. Drought is more tolerant in coastal sites.
Small species may be planted in drifts along the front of borders and larger ones farther back for spectacular statements. Intermingle with other sun-loving perennials or mix into the vegetable garden for added late-season color.
When different agastache varieties are grown together they may cross-pollinate and their seedlings may not be true to the parent plant. Deadheading and removing volunteers helps prevent cross-pollination, although many gardeners rely on self-sowing for prolonged presence since agastache can be short-lived, especially in clay soils.
Agastache foeniculum (anise hyssop or giant blue hyssop): anise scented 3 ft. high by 2 ft. wide with purplish blue flowers; tolerates Sonoma County winters better than other species.
A. hybrids: colorful names such as ‘Apricot Sunrise,’ Firebird,’ ‘Tangerine Dreams,’ and ‘Tutti Frutti’ are among the most commonly available in nurseries.
A. rugosa(Korean hyssop): 3-5 ft. tall by 2 ft. wide with violet blue flowers that bloom the first season after planting; tolerates wetter feet than most varieties.
A. rupestris(licorice mint): 2 ft. high and wide with narrow gray-green leaves and coral flowers.
A. mexicana (giant Mexican lemon hyssop) 2-5 ft. tall by 1-ft.wide, orange flowers, lemon-scented leaves.