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Ochna serrulata (Hochst.) Walp. 1846
pronounced: OCK-nuh sir-yoo-LAH-tuh
(Ochnaceae – the Mickey Mouse Bush family)
common name: Mickey Mouse Bush
Ochna is from the Greek οχνη (ochné), a wild pear; serrulata is from the Latin serrula, a small saw, referring to the serrulate edges of the leaf. The common name comes from the similarity of the fruit, when the seeds have turned black, to Mickey Mouse’s face. Ochna serrulata was first described by the German naturalist Christian Ferdinand Friedrich Hochstetter (1787–1860). Hochstetter published numerous writings on botany, mineralogy and natural history, as well as on theology and education (he was a Protestant minister by profession). The genus Hochstetteria (now known as Dicoma) of the family Asteraceae was named after him, and he himself named a good many species (his author abbreviation is Hochst.).
This plant has been declared a noxious weed, category 4, in NSW, and is listed as an environmental weed by the Brisbane City Council. It was imported from South Africa as an ornamental, as has become an invasive weed in parts of Queensland (in the area around Bowen and on the coastal belt from about Maryborough south) and on the NSW coast as far south as about Nowra. It is very hardy, and has the potential to spread south to invade the remainder of the NSW coast, and to ‘join up’ the 2 areas of Queensland already invaded. It is very difficult to eradicate: it is quite resistant to most herbicides, and, even if cut down to the ground, it resprouts vigorously in the form of multi-stemmed trunks; it readily invades bushland, crowding to form dense thickets in which nothing else seems able to survive, and the ground becomes choked with seedlings. Natural regeneration is completely blocked.
The North Shore of Sydney is particularly heavily infested with the plant. Its berries are now a major food source for Currawongs. The Currawongs originally migrated between Sydney and the Blue Mountains each year but, encouraged over the last 20 or so years by an abundance of food (from rubbish bins, pet foods, residents feeding them, and the proliferation of berry-fruited plants in gardens and bushland) now live permanently in Sydney. Apart from the fact that these birds are merciless and efficient predators of small birds (and eggs from nests), they are also the chief culprits in spreading the Mickey Mouse bush.
I have come across only two of these bushes on Magnetic Island, but I should be surprised if our Currawongs are not busily spreading the seeds; and the plant has the potential to become yet another serious threat to our native plants.
All that being said, Ochna serrulata is a very attractive plant! It is a strongly rooted shrub growing to about 2.5 m high. The leaves are oblong to elliptic, 2–6 cm long, shiny, with toothed margins. The leaf stalk varies from practically nothing to just over 1 cm long. The fragrant yellow flowers are usually about 2 cm in diameter, but they are not often seen, as the petals tend to drop soon after the flowers open. 4–6 fruits grow from each flower. These succulent fruits are round, originally green, paling to almost white and then turning black when they are ripe. They are surrounded by sepals that are green at first, and then become enlarged and red, turning down when the fruit is mature – these groups of sepals, each almost 1 cm in length, are often mistaken for the plant’s flowers.
Caterpillars of the Crotalaria Podborer Argina astraea feed on the plant.
Photographs taken at Picnic Bay 2008-2011
Page last updated 8th January 2017