By Carl Wilson, Colorado State University Cooperative Extension Agent, Horticulture
Hyssop are an exciting group of aromatic plants making a big splash in the plant world. Members of the Agastache genus, hyssop are known for their brightly colored flowers and for attracting hummingbirds and butterflies to the garden. They are generally hardy to Zone 5 Front Range gardens and many can be grown as annuals in containers elsewhere.
Sunset hyssop, A. rupestris, grows to 2 feet in height and bears orange flowers with sunset lavender buds. Brushing against the plants thread-like leaves releases a pleasant root beer aroma. Plant in full sun to partial shade.
Hummingbird mint, A. cana, is scented of bubblegum. It reaches 2 feet in height and 3 feet in width in full sun. The mid to late summer flowers are rose-pink in color.
Hyssop (Agastache aurantiaca) CORONADOTM
Other hyssops are being introduced to Colorado and tested for their cold tolerance. These include Honey Bee White hyssop, A. rugosa, a 4 feet tall, white blooming giant suitable for the back of borders. Another that can be trialed is the violet-blue flowering Korean hyssop, A. rugosum, that reaches 2 feet in height.
Hyssop is best transplanted when temperatures are warm and are definitely not for fall planting. Avoid water-logged soils.
For late season bloom and fragrance, plant hyssop.
Photos: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010