Isodon umbrosus is a perennial found in beech forests, with downward hairs on stems and a height of 20-80cm. Blades with 0.5-2cm long petioles are of opposite phyllotaxis, 5-15cm long, 1.5-3.5cm wide, oblong-like, lanceolate, with serrations on margins and sparse hairs on surfaces. Branch tips bear spike-like inflorescences and set blue-purple, 8-9mm long labiate flowers; upper lips bend backward and cleft themselves into four, and the lower lip is navicular. Bloom time.