Culture
Winter hardy to USDA Zones 9-10. Best in moist, fertile, well-drained soils in full sun. Established plants tolerate some soil dryness. In St. Louis, grow in containers that must be overwintered indoors in a bright cool sun room or greenhouse.
Noteworthy Characteristics
Callistemon citrinus, commonly called scarlet bottlebrush, lemon bottlebrush or red bottlebrush, is native to Australia. It is a large evergreen upright tropical shrub that will grow to 10-15’ tall in its native habitat. It is commonly grown as a specimen or hedge in frost-free climates. It can also be trained as a tree to 25’ tall. In containers in colder climates, it more commonly is grown as a 3-5’ tall shrub or trained as a small standard. Flowers feature numerous bushy bright red stamens in rounded to cylindrical spikes (to 4” long) that resemble bottlebrushes. Flowers bloom intermittently throughout the year in frost-free areas, but more typically in summer in colder climates such as St. Louis. Flowers are attractive to bees. Lance-shaped to narrow-elliptic leaves (to 3” long) emerge coppery before maturing to medium green. Leaves have a lemony scent when bruised.
The genus name Callistemon comes from the Greek words kalli meaning "beautiful" and stemon meaning "stamen" in reference to the showy stamens present on most species in this genus.
The specific epithet citrinus means "related to citrus", in reference to the fragrant leaves.
Problems
No serious insect or disease problems. Watch for spider mites and scale, particularly on indoor plants.
Uses
Specimen tree or hedge in frost-free climates. Container plant or houseplant in colder climates.