Plant of the Week

Map of the United States showing states. States are colored green where the species may be found.
Range map of threadleaf giant hyssop. States are colored green where the species may be found.

A flower cluster of threadleaf giant hyssop.
A flower cluster of threadleaf giant hyssop. Photo by Charlie McDonald.

Threadleaf giant hyssop showing the gray-green stems and leaves.
Threadleaf giant hyssop showing the gray-green stems and leaves. Photo by Charlie McDonald.

Threadleaf giant hyssop (Agastache rupestris)

By Charlie McDonald

Threadleaf giant hyssop is in the mint family (Lamiaceae), which has about 3,500 species worldwide, many of them ornamental and economically important for their essential oils. The genus Agastache has about 30 species native to North America and Asia. Members of the genus Agastache are often called giant hyssops, but this name is a poor choice because these plants have little in common with the true hyssop (Hyssopus officianalis), which is a Mediterranean herb with both ornamental and medicinal values. For this reason, agastachesin the garden trade are now often called hummingbird mints, a more pleasing and appropriate name because these plants are copious nectar producers unsurpassed at bringing hummingbirds into a garden.

mosquito plant
This is not threadleaf giant hyssop, it is mosquito plant (Agastache cana) another one of the native Southwestern hummingbird mints becoming popular in xeriscape gardening. Photo by Charlie McDonald.

Threadleaf giant hyssop is a Southwestern native from the mountainous regions of southeastern Arizona, southwestern New Mexico, and northern Chihuahua, Mexico. It has gray-green stems and thread-like gray-green leaves. It blooms from mid-summer through fall with numerous spikes of orange flowers with lavender buds. Crushed leaves have a pleasant fragrance.

This plant and other hummingbird mints are becoming very popular in Southwestern xeriscape gardening. They are sun and heat-loving and prefer well drained nutrient-poor soils. They are adding new colors and textures to the casual natural look now popular in Southwestern gardening. In addition, they really do attract hummingbirds! Sources of these plants can be found by doing an internet search using the key word "agastache".

For More Information: PLANTS Profile - Agastache rupestris, threadleaf giant hyssop

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Louisiana Trillium (Trillium ludovicianum).
Louisiana Trillium (Trillium ludovicianum)