1. A Japanese shrub that resembles members of the genus Spiraea; widely cultivated in many varieties for its dense panicles of flowers in many colors; often forced by florists for Easter blooming; SYN. spiraea, Astilbe japonica.
2. Any rosaceous plant of the genus Spiraea; has sprays of small white or pink flowers; SYN. spiraea.
Any herbaceous plant or shrub of the genus Spiraea, family Rosaceae, which includes many cultivated species with ornamental panicles of flowers.