Callistemon viminalis or Weeping Bottlebrush is a large shrub or small tree native to New South Wales, Australia. The plant has a graceful weeping habit reaching a height of 20-30 feet (6-9 m) and a 15 foot (4.5 m) spread. Leaves are narrowly lanceolate up to 4 inches (10 cm) long and are light green in color. The brownish gray bark provides a very attractive contrast with the light green leaves and red flowers. This is a fast growing plant that does very well in containers, although it will need some selective pruning to keep it from getting top heavy. The plants are hardy in the landscape in USDA zone 10-11.
Blooming: In the greenhouse, our plants bloom in early to mid spring. The bright red brushes are very showy against the light green foliage. Individual flowers are 1 inch (2.5 cm) long.
Culture: Callistemon viminalis need full sun to light shade, with a well-drained soil mix. In the greenhouse, we use a soil mix consisting of 1 part peat moss to 2 parts loam to 2 parts sand. The plants are well watered and allowed to dry slightly before watering again. Plants in container cannot thrive in drought-like conditions. We fertilize the plants only once in the summer, after flowering, with a balanced fertilizer. Too much fertilizer will give a lot of growth but at the expense of flowers. Also after flowering, we selectively prune specimens back to keep them from getting too top heavy. During the winter months, we move our plants to the cool rooms with a nighttime temperature of 48°F (9°C). During this period, water is somewhat restricted, but the plants are not allowed to dry out thoroughly.
Propagation: Callistemon viminalis can be propagated by cuttings, but they are very slow to root. Seeds are the best way to start new plants. The very small seed should be sown in a peat and sand mix and will germinate in 14-60 days at 70°F (21°C). Seed should be surface sown.
Callistemon viminalis was featured as Plant of the Week March 30-April 5, 2007.
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Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.