Caesalpinia gilliesii, or Yellow Bird of Paradise, is a fast growing shrub or small tree native to Argentina. The plant is semi-evergreen, and will lose all of its leaves in cooler climates. Plants reach 5-10 feet (1.5-3 m) tall with a spread of 4-6 feet (1.2-1.8 m). Leaves are bipinnate, 3-5 inches (7.5-12.5 cm) long and are bluish green and very ferny in appearance. Bark is smooth and grey green.
Flowers are borne at the tips of branches in spring and early summer and then sporadically until fall. The flowers are solid yellow with bright red 4-5 inch (10-12.5 cm) stamens. They are very fragrant and showy. Flower open in late afternoon and individual flowers last one day. You can watch the flowers open, which is fairly dramatic given the flower size. This process takes about 4 hours from a closed bud to a fully open flower.
Caesalpinia gilliesii need full sun to very light shade with a well drained soil mix for containers. We use a soil mix consisting of 1 part peat moss to 1 part loam to 2 parts sand, with small gravel added to increase drainage. Plants are in the legume family and have the ability to fix nitrogen. It has been my experience that the plants do not need fertilizers. Plants are well watered and allowed to dry before watering again. In the landscape, they are very drought tolerant. During the winter months, the plants are put in cold rooms where the nighttime temperature drops to 48° (9°C). Plants will lose their leaves then and watering should be monthly during this period.