Microseason: Prunella Wilt

SUMMER

SUMMER SOLSTICE

PRUNELLA WILT

21 - 25 June

Prunella with its violet flower spikes, appear briefly before withering in the heat. Utsubogusa has long been used in traditional Japanese medicine for its cooling and anti-inflammatory properties. In traditional medicinal practices, it has been categorized as bitter and cold, suited to clearing internal heat and reduce swelling.

Utsubogusa can be used as a gargle to relieve sore throats or compress to calm eye inflammation, sprains, bruises, swelling, and mild fevers. In more recent years, studies have identified rosmarinic acid, ursolic acid, and flavonoids in the plant, associated with antiviral and antioxidant effects.

The flowering spike is harvested just before full bloom, typically between mid-June and early July, when medicinal compounds are at their peak. The plant is cut above the root to allow regrowth, then dried in the shade to preserve potency. Stored properly, it can be used throughout the year.

Utsubogusa may be prepared either fresh or dried, with notable differences in taste and function. Freshly picked flower spikes yield a tea with a light bitterness, grassy aroma, and gentle diuretic effect. While it must be consumed immediately, it’s gentle support of the body is appreciated as the days become hotter. In contrast, sun-dried utsubogusa produces a darker, more bitter concentrate with stronger medicinal effects. This form is preferred in Kampo practice and allows for long-term storage and broader application including use as a wash or gargle. Sun-drying allows us to maintain utsubogusa in our medicine cabinets for the year ahead.

Photo credit: Tajima Garden