The Butterfly Bush, a native of Brazil and other tropical regions, is a medium sized fast growing evergreen flowering shrub and a member of the Royal Poinciana family. It is easily trained and pruned to tree form and can attain a height of 12 feet or more. Cassia is widely grown and well adapted to hardiness zones 9 to 11. It is also a good choice for container growing if properly pruned. It is also known as the Winter Cassia and the Christmas Cassia.
Foliage is dark green and the leaves consist of three to five pairs of leaflets. Although evergreen, foliage may yellow and drop if temperatures during the colder months fall to the thirties or below. If a hard frost is encountered, cut the entire plant down to ground level and throw a shovel full of soil over the stump. New growth will emerge when the weather warms up in spring.
Beginning in late fall, Cassia puts out a stunning display of spectacular deep golden yellow bloom clusters which will last and continue through December if there is no damaging frost. Flowers are very attractive to butterflies and bees. After flowering, the plant produces brown cylindrical seed pods 5 to 12 inches long.
Cassia grows and flowers best in full to partial sun, but will tolerate part shade. It is not fuzzy as to soil condition, but as any other plant, will respond well to a little care such as regular watering and an occasional dose of fertilizer. Late spring and early summer is the time to pinch back growing tips which will encourage branching and increase flower production.
Sprawling evergreen shrub to 4 m (13 ft) tall (or wide), with somewhat zigzag, sparsely hairy stems. Leaves alternate, stalked, even-pinnately compound, with 3-6 pairs of leaflets, larger ones at leaf tip; leaflets to 4 cm (1.6 in) long, oblong with rounded tips; petioles with gland above, between lowermost leaflets (and occasionally between others). Flowers yellow or yellow-green, 3-4 cm (1.2-1.6 in) across, in 3- to 12-flowered racemes near stem tips; stamens with prominent, curved filaments. Fruit a brown slender pod, cylindric, glabrous, 7-12 cm (3-5 in) long. Synonym Cassia bicapsularis.
- Scarify the seeds by nicking or sanding the seed coat.
- Soak the seeds in water for 24 hours.
- Put a mixture of potting soil and sand or perlite into a pot with drainage holes in the base.
- Sow the seeds on the soil.
- Cover the seeds with a layer of soil that is 0.5 inches thick.
- Water the seeds. Keep the soil moist but not wet.
- The seeds take 3-6 weeks to germinate.
- When the plants are a few inches tall, they can be transplanted.