Biancaea decapetala
Credits
Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Biancaea decapetala' from the website Trees and Shrubs Online (treesandshrubsonline.
Common Names
- Mysore Thorn
Synonyms
- Caesalpinia sepiaria var. japonica (Siebold & Zucc.) Gagnep.
- Caesalpinia japonica Siebold & Zucc.
- Caesalpinia sepiaria Roxb.
Other taxa in genus
Editorial Note
Treated by Bean under the synonym Caesalpinia japonica.
A deciduous, very thorny shrub, of straggling or scandent habit, not more than about 8 ft high when left to itself, but growing at least twice as high when trained up a wall. Branches not downy, armed with strong decurved thorns 1⁄4 to 1⁄3 in. long. Leaves doubly pinnate, 12 in. or rather more long, each of the three to eight pairs of main divisions (pinnae) carrying six to ten pairs of leaflets; the common leaf-stalk is armed at each joint with one erect and two decurved prickles, and irregularly in between. Leaflets oblong or obovate, rounded at the apex; 1⁄2 to 1 in. long, 1⁄4 to 1⁄2 in. wide; almost or quite glabrous. Racemes up to 12 in. long, 4 in. through, carrying twenty to over thirty flowers, each on a glabrous, slender stalk 11⁄4 in. long. Flowers canary yellow, 11⁄4 to 11⁄2 in. across, the upper one of the five petals the smallest, and striped with red. Stamens ten, red, 5⁄8 in. long, forming a conspicuous cluster in the centre of the flower. Pod 3 in. long, 1 in. or more wide, flat, carrying six to nine seeds. Bot. Mag., t. 8207.
Native of Japan and China; introduced by Messrs Veitch, who first flowered it in their Coombe Wood nursery in 1887. It succeeded well there on a sunny slope, and occasionally produced seed; but at Kew, in the open ground, it has always been a failure, although it may live for some years. It has grown well on a west wall, and in one of the bays outside the Temperate House. A plant on the potting shed in the R.H.S. Garden at Wisley flowers profusely. It was damaged in the winter of 1962–3 but has since recovered. There are few shrubs more beautiful either in leaf or flower, and it would be well worth growing in a sunny recess where it could be covered in winter. It is one of the most fiercely armed of all cultivated shrubs. Propagated by layers. Flowers in June and July. Nearly allied to this is:
[Bean also recognised Caesalpinia sepiaria (now treated in synonymy) as a distinct species, ‘common throughout India and much used there as a hedging plant [and] distinguished by its very downy wood and less lax racemes.’ MD 4/2025]
