This is a surprising plant.
Its soft leaves make it look a rainforest species, but this may not be the case.
There are records of it being found in rainforests. However if they were seen when not fruiting, it’s a fair chance that the plants were actually bellfruit’s rare and endangered relative, Gyrostemon osmus, which was generally unknown until it was studied and named in 2005. It looks very like bellfruit, but has seed capsules that open along a dorsal split, unlike bellfruit capsules which drop their seeds out of the bottom.
The remainder of bellfruits's relatives, both Codonocarpus and Gyrostemon species, are plants of the desert or dry country out west.
Bellfruit itself is “Mr In-between”. Found in coastal and sub-coastal sites, it hangs about on the edges of dry rainforests and in disturbed areas hoping for fire to help its seeds germinate.
Australian ecosystems can be broadly divided into two groups – those (like rainforests and vine thickets) which are damaged and reduced by fire, and the “fire ecologies”, which depend on fire for good health. The latter are populated by plants which thrive with regular fires, and may even depend on them for the species’ long term survival. If the rainforest specimens are all actually Gyrostemon osmus, then we can place the true bellfruit, Codonacarpus attenuatus on the "fire" side of the fence.
The plants above, which I photographed a few days ago, were in a typical site. It is a large council-owned reserve in the Merritt’s Creek Road area which was covered with fairly open vegetation until it was given a clean-up burn in 2010. The result, in a mere four years, is this extremely thick growth of wattles Acacia neriifolia (another fire-loving plant) and bellfruit (centre plant with light grey trunk). Loving the fire, they came up like hairs on a cats' back from seed lying dormant in the soil.
The scrub is now about 6m tall. Crowding has resulted in tall thin plants with bare trunks and dense leafy growth at the top only.
Not all the bellfruit trees in the scrub have seeds on them, because the species has separate male and female plants.
Photo by Dougal Johnston
There are, however, plenty of male plants to ensure fertilisation of the female plants. They were heavily laden with their little green "bells". As the species is wind-pollinated, there is always a chance that having too few plants in the area might result in uneven pollination, with pollen failing to reach all the female flowers. This is clearly not the case there!
Bellfruit trees are not often grown in gardens, largely because they are not often available for purchase. Seeds are difficult to germinate, but are known to do better if soaked in smoke water.
Gardeners would need to put in several plants, to be sure of having specimens of both sexes, if they want to get the ornamental "bells".
Specimen plants grown in the open are likely to be as little as one third the height of the plant shown at left, and to have canopy almost to the ground.
In gardens, a useful planting style can be to put a small group of bellfruit close together. This can result in plants (of both sexes) forming a united canopy, looking rather like a multi-stemmed large shrub.
Like many other fast-growing pioneer trees, bellfruits probably have a relatively short lifespan.