Native to northern China, Korea, Japan. Woody-stemmed plants with finely divided, almost ferny foliage and dense clusters of tiny, sweet peashaped flowers in spring and summer. Plants can be killed to the ground in a hard winter, but they recover quickly from the roots and bloom on new wood. Even in mild-winter areas, they are more compact and attractive when cut back hard in late dormant season. Provide good drainage. Very heat and drought tolerant. Nearly indestructible.
I. decora. CHINESE INDIGO. To 1212 ft. tall and 3 ft. wide, with arching branches. Narrow, somewhat drooping blossom clusters to 8 in. long hold as many as 40 white blooms suffused with pink. Spreads steadily by suckers to form a patch. Makes good ground cover under trees.
I. heterantha. HIMALAYAN INDIGO. To 48 ft. high and wide, with arching branches. Purplish pink flowers in upright clusters 68 in. long.
I. kirilowii. KIRILOW INDIGO. To 2123 ft. tall, 3 ft. wide, with upright shoots and erect, 5-in. clusters of rose-pink flowers. A. k. alba has white blooms.
I. 'Rose Carpet' (I. pseudotinctoria 'Rose Carpet'). Dense, low-growing plant to 1 ft. tall and 4 ft. wide. Rose-pink blooms appear over a long period from mid- to late summer.