A scientific name quagmire: Lyn Craven of the Australian National Herbarium [Novon 16 468-475; December 2006 “New Combinations in Melaleuca for Australian Species of Callistemon (Myrtaceae)”] argued based on genomic research that the differences between the two genera, Callistemon and Melaleuca are insufficient to warrant them being retained separately and that they should be combined, thus Melaleuca is the preferred genus based on earlier precendence. Thus, I prefer to use the genus Melaleuca for this landscape taxon.
Common: weeping bottlebrush
Origin: Northeast coastal Australia, primarily Queensland, with a small disjunct population in western Australia.
Pronounciation: Mel-a-LOU-ka vi-mi-NAL-is
Sunset 12-24, cold damage in zone 8-9
USDA 8 (with cold protection), 9-11
Landscape Use: Weeping bottlebrush usually best used as a vertical accent tree or focal point. Also good for use around water features where a pendulous upright element is needed. Dwarf cultivars are smaller shrubs used in landscape borders as edging plants or in container pots.
Form & Character: Evergreen, ranging from a small and diminutive prostrate shrub to a weepnig and graceful, medium-sized tree.
Growth Habit: Upright, moderate to 20 to 40 feet with pendulous stems, stems sometimes brittle. In contrast, dwarf cultivars are slow growing, low and prostrate to only 2 feet tall with equal to slighter greater spread.
Foliage/texture: Young leaves reddish, pubescent, mature leaves linear to lanceolate nearly sessile, aromatic; medium texture (dwarf cultivars) to medium fine texture (standard plants).
Flowers & fruits: Red bottle brush flowers (stamens tower above with protruding bright red filaments with sometimes yellow anthers) followed by persistent small round nut-like fruit.
Seasonal color: Striking display of red flowers during Spring.
Temperature: Tolerant to 20oF; suffers if temperatures are above 112oF for an extended period of time.
Light: Full sun
Soil: Well drained, more tolerant of alkaline soils and less prone to show yellow chlorosis than Callistemon citrinus. Dwarf cultivars are more prone to chlorosis in Phoenix soils than is the straight species.
Watering: Infrequently water deeply during the summer.
Pruning: Train rigorously when young to attain upright form and remove crossing branches, elsewise raise the crown base as needed in order to train this plant's form into that resembling a tree.
Propagation: Seed propagation is difficult, whereas cutting propagation is relatively easy.
Disease and pests: None that are significant in the Phoenix area.
Additional comments: Weeping bottlebush is the best acclimated of the former Callistemon species to the harsh environment of the Phoenix area. The red bottle brush flowers strongly attract bees and to a lesser extent, hummingbirds. 'Captain Cook' (a seedling selection), 'McCaskillii', and 'Little John' (selected by Ken Dunstan of Alstonville, New South Wales) are all dwarf cultivars that make excellent low maintenance border edging or container plants.