Yellow Giant Hyssop

October 8th, 2020

Agastache nepetoides

The yellow giant hyssop, a member of the mint (Lamiaceae) family, is a robust herbaceous perennial found throughout much of the eastern United States and Canada. As a member of the mint family, it has the characteristic square stem (in cross-section), but it does not have a particularly intense scent, a characteristic of the family. However, its leaves are quite bitter and, therefore, it is a deterrent to deer.

physical description

This plant achieves a height of between 4 and 7 feet tall. The greenish leaves are 6 inches long and about 3 inches wide with coarsely toothed margins. Each major stem and secondary stem terminate in a spike of multiple pale-yellow flowers. These flowers are first found in mid-summer and extend into early autumn. The spikes can last 1 - 2 months but the individual flowers are very short-lived.


The native yellow giant hyssop is found, and does best, in deciduous forests, thickets, woodland borders, and power line cleared spaces in wooded areas. It prefers partial sun to light shade and mesic to moist, loamy soils. It does not do well in dry or drought conditions. This species grows well in hardiness zones 4a to 9b. Chattanooga is in zone 7 and, thus, this species will do well here.



Since the separate, individual flowers are so small, the yellow giant hyssop is frequently planted for the green vegetation rather than for the flowers displayed.

This plant looks best in gardens and yards when planted in masses to actively show off the flower spikes.

interesting information

The yellow giant hyssop attracts many insects for pollination and honey bees use the nectar in the production of honey. It also attracts butterflies.

This species is endangered in some states (e.g., Connecticut) but there is no Federal protection for it.

Other species of hyssop has been used in England since the 15th century and in the Middle East since the 3rd century BC.

Yellow giant hyssop plants are grown and available in the arboretum of the Reflection Riding Arboretum and Nature Center.

Charlie is a retired professor and Biological Oceanographer. He taught five courses in the University of Georgia System for many years from his home base in Savannah, Georgia.  

Charlie loves hiking at Reflection Riding, teaching children about the ecology of the area, and interacting with the Reflection Riding staff. They are GREAT!

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Posted by Charlie Belin  | Category: native plants
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