The delicate blue butterfly bush flowers swarm in clouds at the tip of each branch.
A closeup of a blue butterfly bush flower shows that they really do vaguely resemble a butterfly. Click to download a large version of this image for a closer look.
Blue butterfly bush is an open and sprawling evergreen shrub that gets up to 10 ft (3 m) tall and wide, but is easily kept much smaller. It has opposite leaves that are egg shaped, strongly toothed and about 3-4 in (7.6-10 cm) long. The inflorescences, borne at the ends of long arching branches, are panicles 4-10 in (10-25.4 cm) long composed of individual flowers about 1 in (2.5 cm) long, each with three pale blue lobes and one violet blue lobe. The flowers look like little butterflies in two different shades of blue and are produced more or less continuously throughout the summer and fall.
Blue butterfly bush occurs in Kenya and Uganda in East Africa.
Culture Light: Grow this clerodendrum in partial shade. Moisture: Water freely in growth but reduce watering in winter. Hardiness: USDA Zones 10 - 11. Blue butterfly bush performs best in a frostfree climate, but it is root hardy in zones 8 and 9, freezing to the ground in winter, but returning from its roots in spring. Propagation: Blue butterfly bush is easy to propagate from stem or root cuttings, or from rooted suckers.
Jack makes stem cuttings (about the size of a pencil) in late summer to plant out in spring - these were taken four weeks ago and have rooted nicely.
Use blue butterfly bush as a small stand alone specimen or in a mixed border. Prune back this gangly shrub as needed to keep it in check. Clerodendrums flower on the current season's growth, so you can prune them anytime. Cut back the old wood to a pair of buds to improve flowering. In areas that get frost, you can get the most consistent flowering year in and year out by growing blue butterfly bush in a large pot that can be brought indoors when temperatures approach freezing.
There are more than 400 species of Clerodendrum. The members of this diverse genus occur naturally in tropical and subtropical Asia and Africa, and include evergreen and deciduous trees, shrubs, vines and herbaceous plants. Tubeflower, also called Turk's turban, (C. indicum) is a roadside weed now established in the southeastern US, and Cashmere bouquet (C. bungei) is a nuisance invasive weed in South Florida - it is pretty though, click here for photo (800x600). Among the many beautiful ornamental Clerodendrums are flaming glorybower (C. splendens) and pagoda flower (C. paniculata).
The genus name comes from the Greek: dendron, tree; and kleros, chance, a reference to the varied medicinal properties purported for some members of the genus. C. trichotomum, from China, has been shown to lower high blood pressure, and is prescribed in Chinese herbal medicine for a variety of ailments.