Q. A friend sent me seeds of a plant called Rattlebox. How do I get them to germinate, and where should I plant it?

A. You most likely have the seeds of Sesbania punicea,  synonym Sesbania tripetii, a woody, deciduous, small tree or shrub. The specific name ‘punicea’ translates to crimson in Latin, and refers to the brilliantly colored flowers. Other common names are Scarlet wisteria, Chinese rattlebox, Red sesbania, Purple sesbane, and False poinciana.  These plants can get to 4 meters ( ~15 feet) in height. They have bright green, 10-20cm long compound leaves with 10-40 leaflets opposite each other. The dramatic red flowers show up in early spring-summer in dense racemes that cascade down, the pea-like blossoms eventually maturing into hundreds of brown, winged seed pods. The seed pods are filled with 3-9 seeds that rattle in the pods when shaken, hence the common name. Native to southern Brazil, northeastern Argentina, and Uruguay, this plant has shown up in the ornamental plant trade around the world because of the lovely bloom.

This plant has a terrible reputation. It is considered a serious weed in parts of Africa, northern Florida, eastern Texas, southern Georgia and recently in the central valley of California.. Within one year the plant produces large quantities of viable seeds that spread via water down creek banks, making it a riparian nightmare. The seedlings can form solid stands along creek banks, decreasing biodiversity and wildlife habitat.  Young plants are pulled by hand or yanked out with weed wrenches, large plants need to be cut and treated with an herbicide. All parts of this plant contain highly toxic Saponic glycosides, and should not be planted in any garden where pets( reptiles, birds , mammals) or children might have access. The symptoms range from nausea to respiratory failure and the results may be fatal.

There are many reasons not to plant those seeds. Although attractive in bloom, this plant is poisonous, invasive, and difficult to eradicate.  

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