Purple Giant Hyssop
aka Korean Mint
aka Wrinkled Giant Hyssop
aka Blue Licorice
aka Huo xiang
aka Indian Mint
Patchouli Herb
"Purge me with hyssop, & I shall be clean."
Psalm 51:7
Agastache rugosa or Purple Giant Hyssop is a seriously erect perennial with stiff, toothed leaves having a wonderful spearmint-licorice smell to leaves & flowers. As a garden ornamental, it is nearly identical to A. foeniculum with which it hybridizes, the cultivar 'Blue Fortune' being a cross of both species.The bluish purple stubby flower-spikes on Korean Mint's long stems are suitable for bouquets, & long-lasting in the summer garden. Shown above in July (2002) & below respectively in June & July (2004), it is not unusual for flowers to linger until October.
The flowers are usually two to four inches tall (now & then longer), above three foot tall stems from a slowly spreading clump.In June & early July the flowers are quite stubby, fat & conical. By mid-August if not sooner, the blooms, which keep growing, are reaching their full four inch height & are preparing to seed. When they are turning to seed, they begin to look like furry green shortened tabby-cats' tails.
Extract of A. rugosa are mixed with extracts of Pogostemon patchouli in herbal perfumes associated with the hippy era. THe same two herbs as powders or liquids continue to be offered medicinally as Patchouli or Huo-xiang.
A native of China, Vietnam, Laos, Korea, & Japan, Purple Giant Hyssop has long been used in traditional Chinese herbal remedies. It is one of "the fifty fundamental herbs" & reputedly assists an upset stomach, arrests sweats or fever, summertime colds, & heightens energy.Whether most of the alleged uses are malarky or not is difficult to assess on the basis of the available studies, most of which were concocted in China by advocates rather than impartial researchers. A study by Wang et al conducted at China's Agricultural University of Hebei,in 2001 found that A .rugosa extracts was one of many effective herbal fungicides for potato crops. It's usefulness as a human medicine is not as clear-cut, as the majority of studies are very poorly modeled. The best resarch has been on methods of improving essential oil production for commercial uses, rather than efficacy.
Antiviral Compounds from Plants by J. B. Hudson (Boca Raton, Florida: CRC Press, 1990) indicates that this hyssop may have a valid antiviral effect which would support it's use as a summer cold remedy, except that it had a measurable effect only when used in alarmingly high doses, the plant's isoflavones having such a low absorption rate from the intestines that claims for it being "potent" are at best a serious exaggeration. But by the tepid evidence thus far available, neither is not entirely devoid of merit.
The leaves & flowers do at the very least make a good herbal tea, one of the best to be gathered fresh from the garden. It seems a reasonable guess that it has the same stomach-settling properties as an ordinary mint tea, but also the same possibility of upsetting the stomach in people who are sensitive to mint.
For dry flowers, hang a long-stemmed bunch flower-heads-down from the ceiling in a warm dry part of the house. In a few days you have perfect dried flowers. Agastache holds its shape & color very well, & will also carry a lingering scent for use in sachets. The late-season larger green "tails" are also worthy of drying.
A forgiving, hardy perennial, it will do well in average to loamy soil, with full or partial sunlight, & is drought-tolerant once established hence a good choice for a roadside sun-garden, which is how we are using it.