Senna didymobotrya
Senna didymobotrya
Safety & Hazards
Senna didymobotrya, like other Senna species, is poisonous[1]. Decoctions from all plant parts can cause violent vomiting and diarrhoea and may be fatal[1]. It is recommended that pregnant women and children take a small dose[1]. The plant is widely used in Africa as a stupefacient poison for fishing[2].
Cultivation Details
Succeeds in tropical and sub-tropical regions, where it is found at elevations from sea level to 2,500 metres[1, 2]. The plant has escaped from cultivation in some areas and shows signs of being invasive[3]. The plant flowers profusely twice a year[2]. When planted as a small shade tree in tea plantations, it is spaced at about 5 x 5 metres[2]. The plant yields a fairly large amount of material for green manuring. About 5 tonnes of green material provides 35.5 kg nitrogen[2]. There are conflicting reports on whether or not this tree has a symbiotic relationship with certain soil bacteria, so it is unclear as to whether this tree fixes atmospheric nitrogen[4].
Propagation
Seed - requires pre-treatment to soften the hard seedcoat and allow the ingress of water[1]. This can be done by soaking the seed in a small amount of nearly boiling water (which cools down quickly and does not cook the seed) and then soaking the seed for 12 - 24 hours in warm water. Alternatively, a small area of the seed coat can be abraded, being careful not to damage the embryo[PFAF]. The seed usually germinates readily - experiments with treated seed gave 75 - 85% germination rate, whilst in the same period only 15 - 20% of untreated seeds germinated[1]. The seeds can germinate both in light and dark conditions and over a wide range of temperatures; however, the optimum germination temperature is 20 - 25°c and the germination rate is very low at 10°c[1]. The seed may be sown in the nursery or directly in the field[2]. Cuttings are said not to be successful[2]. Cite as: Tropical Plants Database, Ken Fern. tropical.theferns.info. 2026-02-20. <tropical.theferns.info/viewtropical.php?id=Senna+didymobotrya>
Pollinators
Insects
References
- [1]Protabase - Plant Resources of Tropical Africa. — http://www.prota.org ↩︎An excellent on-line database with detailed information on over 3,200 species of useful plants of Africa.
- [2]World Agroforesty Centre — http://www.worldagroforestry.org/ ↩︎An excellent online database of a huge range of trees giving very good information on each plant - its uses, ecology, identity, propagation, pests etc.
- [3]Pacific Island Ecosystems at Risk — http://www.hear.org/pier/scientificnames/index.html ↩︎A very good website detailing weed species that have been introduced into the Pacific Islands.
- [4]Nodulation Plants in GRIN Taxonomy — United States Department of Agriculture · http://www.ars-grin.gov/~sbmljw/cgi-bin/taxnodul.pl?language=en ↩︎An online database listing plants that have either positive or negative reports on root and stem nodulation with nitrogen-fixing bacteria.
- [5]Mansfeld's Database of Agricultural and Horticultural Plants — http://mansfeld.ipk-gatersleben.de/pls/htmldb_pgrc/f?p=185:3:4292127278597336 ↩︎Terse details of a huge range of useful plants.
- [PFAF]Plants for a Future — pfaf.org ↩︎