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Callistemon citrinus (Lemon Bottlebrush) - A large evergreen shrub that can grow up to 20 feet tall by nearly as wide with deeply fissured gray bark and 3 inch long by 3/4-inch-wide stiff mid-green lanceolate leaves that are tapered at both ends with an acute sharp tip. The leaves are a silky pink color when first flushing out, have a somewhat menthol lemony scent when bruised, and have many noticeable oil glands when held up to the light, much like a citrus leaf. The individual flowers are bundles of inch long red stamens held in a small greenish calyx that are clustered in a 4-inch-long flower structure that resembles a bottlebrush. These clusters initiate near the tips of stems that continue to produce leaves beyond the flowers. It blooms year-round in coastal California with a peak in the early summer through fall. The woody cup-shaped fruit capsules that follow the flowers are held tight to the stems for many years.
Plant in full to part sun in a fairly well-drained soil and irrigate infrequently to occasionally. It is drought tolerant and cold hardy to around 20 degrees F. Quite tolerant of heat, cold, poor soil, near coastal conditions as well as to predation by deer, and the flowers are quite attractive to bees and hummingbirds. This is a reliable large shrub that can be used as a specimen shrub or hedge or trained up into a small tree.
Lemon Bottlebrush grows naturally in New South Wales, Victoria and southern Queensland, where it is often found in wet or swampy conditions. It was among the first Australian plants brought into general cultivation. Joseph Banks collected dry specimens of it during the voyage with Captain Cook on the Endeavor in 1770 and by 1788 it was in cultivation in England from seed (or perhaps a root) collected at the penal colony established in Botany Bay. It first appeared in California in Colonel James Warren's Warren and Son's Garden and Nurseries catalog in 1853 – Warren is credited with producing the first nursery catalog in the state in 1849 for his nursery he established in Sacramento.
The genus was named using the Greek words "kallos" meaning "beautiful" and "stemon" meaning "stamens" in reference to the long conspicuous and colorful stamens that characterize the flowers of this genus. The specific epithet means "related to citrus" and is thought to be a reference to the fragrant leaves, however the leaves really do not smell that strongly of citrus. Other common names include Scarlet Bottlebrush and Red Bottlebrush.
Melaleuca and Callistemon have long been noted as closely related and separated on the basis that Callistemon stamens were free and those of Melaleuca were in bundles. Carl Linnaeus had described the genus Melaleuca in 1767 and the Scottish botanist Robert Brown first described the genus Callistemon in 1814. As early as 1864 Ferdinand von Mueller, the German-Australian born physician, geographer and botanist who eventually became director of the Royal Botanic Gardens, Melbourne, noted that the difference between the genera was artificial and proposed to unite Callistemon and Melaleuca but it was not until 1998 that some plants in New Caledonia previously described as Callistemon were reclassified as Melaleuca by Australian botanist Dr. Lyndley Alan Craven of the Australian National Herbarium and New Zealand botanist Dr. John Wyndham Dawson. In 2006, using DNA evidence Craven reclassified nearly all species of Callistemon as Melaleuca in his article "New combinations in Melaleuca for Australian species of Callistemon" in Novon (V14 N4) and in 2009 he summarized this in a statement in an article titled "Melaleuca (Myrtaceae) from Australia" in Novon (V19 N4) noting that "During revisionary work directed toward the preparation of an account of Melaleuca L. and it closer allies for the Flora of Australia, the delimitation of Callistemon R. Brown from Melaleuca was considered. The conclusion was reached that Callistemon was insufficiently distinct from Melaleuca to be maintained at generic rank and those species which there was no valid name yet available in Melaleuca were transferred to that genus. This makes this plant's name Melaleuca citrina but until such time that the new names have broad recognition in the California nursery trade we will still refer to these plants as Callistemon.
Though we have grown this species on and off since our nursery was first established, our most recent crops were grown from seed taken off a plant growing in the yard of noted Santa Barbara plantsman John Bleck, who grew it from seed collected in the mid-1990s from a plant growing in the garden of Santa Barbara tree book author and city arborist Will Beitel (1913–1999). We also grow several cultivars with Callistemon citrinus as a parent – see Callistemon for more information on these.
This information about Callistemon citrinus displayed is based on research conducted in our horticultural library and from reliable online resources. We also will relate observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments that we receive from others and we welcome hearing from anyone with additional information, particularly if they can share any cultural information that would aid others in growing it.
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