Callistemon citrinus lemon bottlebrush

Callistemon citrinus, Cedar Hall. Sairus Patel, 5 May 2021

Callistemon citrinus. John Rawlings, c. 2005

Red bottlebrush spikes are borne in profusion in summer, with scattered blooms through much of the rest of the year. Similar to C. viminalis, though a vigorous, multi-stemmed shrub rather than a tree, its narrow leaves are held almost at right angles to the branchlets, stiff and alert where C. viminalis is relaxed. The fibrous bark is quite different, too, shearing away in vertical stringy strips. Look closely at the sticky flowers and you’ll see the stamens are not fused in a ring at the base, as they are in C. viminalis.

The leaves are aromatic when crushed, though citrinus strains credulity. Lemon bottlebrush can be seen behind Cedar Hall and between Hulme and Building 86 in Escondido Village; they are plentiful in campus greenbelts and as hedges in neighboring cities.

The pink-flowered cultivar Callistemon ‘Jeffers’, of uncertain parentage, grows in a hedge at the southwest corner of the vast inner courtyard of the Science and Engineering Quad. Additional hedges can be found along the west side of Ventura Hall and nearby at Cordura Hall.

Melaleuca species produce similar bottlebrush flowers, though there the stamens are fused into five bundles. Some authorities now treat all Callistemon species as Melaleuca, though the Australian Plant Census has declined to follow.

· Callistemon and Melaleuca: Key to Species

Name derivation: Callistemon – see C. viminalis entry; citrinus – see text above.