January 2008 Plant Highlight: Senna artemisiodes

Image of S. artemisiodes

One of the bright spots in the Ruth Bancroft Garden during the winter months is Senna artemisioides (also known as Cassia artemisioides, and by the common names of “feathery cassia” and “silver cassia”).  This is a modest-size shrub from inland areas of Australia, with upright growth to about 6 feet or more (2 m) and bright yellow flowers.  The pinnate leaves bear narrow needle-like leaflets, and these are usually a gray-green or silvery-green color, though some plants are greener than others.  The overall effect is airy or feathery rather than dense.

The flowers on S. artemisioides are cupped, and though they are not large (they are about 1/3 to 1/2 inch across, or 8-12 mm), they are produced so profusely that they make a nice splash of color in the garden.  The dangling pods that follow are initially green, later turning brown and splitting open to show off the shiny black seeds.  The pods range from about 2 to 4 inches long (5 to 10 cm) and persist for a long time.

Image of S. artemisiodides

  Senna artemisioides is easy to grow and is drought-tolerant, making it a good choice for low-water gardening.  It is not fussy about soil type, and it likes plenty of sun.

Plants now classified as Senna were formerly included in Cassia, a related genus.  Flowers in both groups are most often yellow, and they are members of the family Caesalpiniaceae.  In some classification systems, this family is considered as a subfamily within the pea family (Fabaceae).

Text and Photos by Brian Kemble

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