Buddleja grandiflora is endemic to the marshy fields and river margins of southern Brazil, and adjacent areas of Argentina and Uruguay. The species was first described and named by Chamisso & von Schlechtendal in 1827.
Buddleja grandiflora is a shrub 1 – 2 m high, and unlike most South American members of the genus, is hermaphroditic, not dioecious. The young branches are subquadrangular, and covered with a white tomentum, bearing leaves subsessile or with a petiole < 1 cm, narrowly lanceolate, 5 – 10 cm long by 1 – 2.5 cm wide, membranaceous, tomentose or glabrescent above, and lanose below. The yellow inflorescence is 5 – 15 cm long, comprising two orders of branches. The sessile perfect flowers are borne in pairs of cymes, each with 1 – 6 flowers. The tubular corolla is 10 – 12 mm long. Unusually, the spongy seeds have buoyancy cells at their bases enabling them to float and withstand flooding.
The shrub is not known to be in cultivation.
- Norman, E. M. (2000). Buddlejaceae. Flora Neotropica 81. New York Botanical Garden, USA
- Cham. & Schldtl., (1827). Linnaea 2: 596, 1827.