The Genus Kunzea
Norm McCarthy
The first botanical reference to Kunzea was apparently in 1791. It was grown in England and classified as Leptospermum ambiguum. A little later it was included in Metrosideros. However, in 1828 the name Kunzea was applied to the genus in honour of Dr. Gustav Kunze, a German botanist, (1793-1851) and so this unique genus of plants was accorded due recognition, which remains to this day.
Nowadays, approximately 40 odd species are accepted as Kunzea. Apparently a revision of the genus is in progress and perhaps some name changes may eventuate. I believe Ferdinand von Mueller and F. Manson Bailey in the late 1800s sought common ground to include Kunzea, Callistemon, Leptospermum and Melaleuca as one genus. Because of evident botanical dissimilarities, all have remained as separate entities ever since. So much for history!
Kunzeas can be prostrate, small, medium to large shrubs, or even small trees. Branches toughen with age. Leaves are normally small, dense, alternate and quite aromatic. A little pruning when young increases compactness and better flowering ability. Light pruning after flowering is beneficial.
Slow release Osmocote can be advantageous to growth and health of plants. Fish or seaweed solutions are recommended. Most kunzeas occur in southern climates and prefer coastal or nearby areas with good drainage. Moist soils are most suitable and watering is necessary in dry times. New South Wales, Victoria, South Australia and Western Australia have many species, with as many as 20 in south-west WA.
The Western Australian species, where the only two red flowered species occur (Kunzea baxteri and Kunzea pulchella), are indeed outstanding. Grafting of most western species is prerequisite in NSW and Queensland on a suitable rootstock for longevity. Climatic inversion can be a problem for growing the western plants in those two states.
Foliage of kunzeas is always pleasing and ornamental, usually small and crowded even without flowers and free of predators. Maybe it's the aromatic leaves!
Flowers are reliable and attractive and always terminal or axillary/terminal. Many are pink to purple in globular heads, though red, white cream and yellow are well represented in other formations. Many species are most floriferous and a sight to behold in spring and summer. Flowers often vary in presentation as to species. After flowering the fruits form retaining the sepals. When the fruit ripens it sheds the seeds approximately 20-50 in number. However, the floral tube remains persistent on the plant and could contain 2-5 valves.
Kunzeas are normally frost tolerent in most cases. If grown from seed, flowering may take 6 years. However, cuttings taken from mature plants could produce flowers in one year or two at the latest. Better still, grafting onto a suitable rootstock such as Kunzea ambigua can produce flowers within a very short period of time. Grafting creates strong long-lived plants.
My home state of Queensland is home to five Kunzea species. They are:
- Kunzea bracteolata, 1-2 m high x 1-2 m wide, cream.
- Kunzea calida (rare) 1-2 m high x 1-2 m wide, purple globular heads.
- Kunzea ericoides (syn. K.pedunculata), 2-8 m high x 2-5 m wide, cream scented terminal.
- Kunzea graniticola, 2-5 m high x 2-5 m wide, cream semi globular.
- Kunzea opposita 2 m high x 2 m wide, mauve globular heads.
As a matter of interest, Kunzea calida was apparently discovered by F. Mason Bailey, Queensland Government Botanist. He describes it in Queensland Flora Vol 2 in the year 1900 and is a little documented species. Kunzea calida occurs in the Flinders River, Newcastle Range and north Queensland inland areas. Kunzea graniticola occurs north-east and coastal of K.calida. K.graniticola is also found on Hinchenbrook Island and is the furthest known northern species of the genus. I am growing Kunzea calida and Kunzea opposita which are young plants and yet to flower.
Kunzeas are trouble free and are a most desirable genus of attractive plants to grow in any garden. The floral beauty of infinite variation attracts beneficial insects and nectar loving birds.
From 'Native Plants for New South Wales', newsletter of the Australian Plants Society (NSW Region), October 2004.
Australian Plants online - 2006
Association of Societies for Growing Australian Plants
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