Morphological features
Ruolanxiang
A perennial herb. Stems erect, 40-130 cm tall, glabrous or nearly so, green, obtusely quadrangular, sulcate and striate, sterile branches only adnate to ground. Leaves sessile or subsessile, ovate-oblong or oblong-lanceolate, 3-7 cm long, 1-2 cm wide, apex acute, base broadly cuneate to subrounded, margin acutely and irregularly serrate, herbaceous, green above, gray-green below, lateral veins 6-7 pairs, with midvein more or less concave above conspicuously raised and whitish below. Verticillasters borne on top of stems and branches in interrupted but upwardly crowded cylindrical spikes 4-10 cm long; bracteoles linear, longer than calyx, 5-8 mm long, glabrous; pedicels 2 mm long, glabrous. Calyx campanulate, coherent teeth 2 mm long at flowering, outside glabrous, glandular punctate, inside glabrous, 5-veined, inconspicuous, calyx teeth 5, triangular-lanceolate, 1 mm long. Corolla lavender, 4 mm long, glabrous on both surfaces, crown tube 2 mm long, limb with 4 lobes, lobes subequal, upper lobes retuse. Stamens 4, projecting, subequal, filaments filiform, glabrous, anthers ovoid, 2-loculed. Styles much projecting from corolla, apex equally 2-lobed, lobes subulate. Disk flat-topped. Ovary brown, glabrous. Fl. [1]
Habitat distribution
Native to southern Europe, Canary Islands, Madeira, USSR. It is cultivated or escaped into the wild in Hebei, Henan, Jiangsu, Zhejiang, Guangdong, Guangxi, Sichuan, Guizhou, Yunnan, and elsewhere in China, and wild in Xinjiang. The type was taken from Europe. [1]
Growth habit
Happy with humidity, highly adaptable. It is cold hardy, and can overwinter in the open ground in Shanghai, but the plant grows poorly after 3 years of continuous planting, and the cold hardiness is obviously weakened. Need sufficient sunlight, not suitable for cultivation in the shade.