Calothamnus species

Synonyms -

Family: Myrtaceae



Evergreen shrubs or small trees and commonly referred to as "One-sided bottlebrushes" because many species have toothbrush like flower heads. The leaves are usually crowded, slender and circular in cross section.




First leaves:


Usually crowded, often long and circular in cross section
Stipules - None or tiny.
Petiole -
Blade - Simple, dotted with oil glands, smooth edges, often leathery.


Flower head:

Often has a toothbrush like inflorescence. Small cluster or dense spike, often on one side of the stem and never terminal. No bracts.


Usually red. Radially symmetrical. Stalkless. Floral tube is cup shaped. Anthers mature and shed pollen before the ovary of the same flower is receptive to ensure cross pollination.
Ovary - Inferior or almost so. Nearly always 3 celled with 4-many ovules per cell
Style - Simple, terminal, very slender.
Stigma - Small, head like.
Sepals - Triangular, connected to the floral tube. 4-5 free and usually green and leafy with papery edges.
Petals - 4 or 5, free, clawed, overlapping, longer than the sepals and usually thin and membranous. They usually fall off before the anthers mature.
Stamens - 5 - many in 4-5 bundles opposite the petals, usually red and > 15 mm long. Much longer than the petals. Free filaments arise near the top of each bundle
Anthers - 2 elongated, parallel cells that shed pollen by a lengthwise slit. Erect and attached by the base.


Dry, woody capsule, 3 valved, often crowned by woody sepals. Seed released through slits at the top (midway between partitions) when ripe.




Taproot with many laterals.

Key Characters:

Trees or shrubs
Leaves with aromatic oils.
Flowers actinomorphic (radially symmetrical)
Floral tube well developed.
Sepals 4-5, connected to the floral tube.
4-5 Petals free.
Ovary inferior or half inferior.
Ovules 4-many per cell.
Stamens in bundles of 4 or rarely 5, usually red, >15 mm long and/or at least 4 times longer than the petals.
Anthers erect, attached by the base, opening by a longitudinal slit
Fruit dehiscent, 3 valved or rarely 2 valved capsule
Adapted from B.L. Rye.


Life cycle:




By seed.

Flowering times:

Seed Biology and Germination:

Vegetative Propagules:




Population Dynamics and Dispersal:

Spread by seed.

Origin and History:

All species native to south western Australia.


ACT, NSW, NT, QLD, SA, TAS, VIC, WA as ornamental plantings.





Plant Associations:



Ornamental, shelter.


Some species have the potential to become environmental weeds.


Not recorded as toxic.


The Wildlife Conservation Act prohibits removal of native plants from the wild in their native range on government land.

Management and Control:

Manual removal is usually effective.


Eradication strategies:

Burning followed by bull dosing or chaining is usually the most cost effective for large stands.
Individual trees can be sawn off close to ground level and the stump painted immediately with Access. Basal bark spraying with Access® in diesel is effective. Saplings can be sprayed overall with Garlon, Grazon or glyphosate.

Herbicide resistance:

None reported.

Biological Control:

Unlikely because it is an Australian native species.

Related plants:

One-sided Bottlebrush (Calothamnus validus) - Weedy and has escaped from plantings.
Calothamnus quadrifidus - Weedy and has escaped from plantings.
Agonis spp.
Beaufortia spp.
Callistemon spp.
Calytrix spp.
Chamelaucium spp.
Calothamnus spp.
Darwinia spp.
Eucalyptus spp.
Kunzea spp.
Leptospermum spp.
Melaleuca spp.
Verticordia spp.

Plants of similar appearance:


Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne).

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia).

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Marchant et al (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P387-390. Diagrams.

Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne).


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