For those who are curious to try the flavour of bumble fruits (also called native caper, or Mitchell’s caper), now is the time to look for the fruit.
It’s also the time to find ripe seed for planting.
I have read that the fruits change colour when ripe, becoming purplish or orange, but have found this not to be the case here.
The indicator of ripeness is simply a softening, and slight cracking of the skin to reveal the yellow insides.
These fruits were sweet and tasty, with no hint either of astringency or kerosene flavour, as mentioned by other writers. However, bumble fruit are full of seeds, and the flesh clings to them very stubbornly. If you don’t want to swallow the seeds (which I don’t) then there is not much you are actually able to swallow.
The seeds are said to have a peppery taste, but I found myself unwilling to chew them, to discover whether the mixture of sweet and peppery was agreeable. Perhaps other, braver readers have done this? If so, do write and let me know!
To quote “Australian Plants Online” (http://asgap.org.au/APOL2009/mar09-s2.html) “The seeds are peppery and should be removed from the flesh.” In practice, this is quite difficult to do.
The same site also says “ Fruit can be eaten raw or used in desserts (eg. ice cream, gelato, mousse, etc.) and cordials. Can also be added to savoury dishes like casseroles, curries, rice and couscous.”
However, to collect the amount of fruit needed for more than the smallest bit of culinary experimentation would be environmentally irresponsible. The environment needs its seeds, both for the regeneration of the plants (dry rainforest plants like this species are on the decline almost everywhere in our district) and for the fauna that eat them.
I hope that those who try the fruit will compensate for their actions by planting some of the seed. Collecting “bush tucker” in our district was once an acceptable activity, but the conditions that made it so (5% of the current Australian population, and 1,000 % of the existing native plant numbers) have long since vanished.
Bumble trees can be found by the roadsides west of Toowoomba, wherever scrub grows.
You will notice that these mature plants have few if any prickles, in strong contrast to their younger selves, which are little prickly monsters.
This one is growing at Peacehaven Botanic Park.
Bumble trees are well worth growing, if you have the space for a small prickly tree. They are rather slow-growing, taking a very long time to reach their mature size of about 4m high and the same wide. The more likely garden plant, in your lifetime, is a slender plant 2m high and 1m wide.
This is one of our very best butterfly host plants, providing caterpillar food for at least four local species of butterfly.
It also has the loveliest flowers of all the local native caper species.
The flowers begin to open in the late afternoon, and are at their best at night, an indication that they are pollinated by night-flying insects (and a good reason for planting one close to the house, where you can see them at their best). They may release a perfume at night as well, but this is something I have never investigated.
They begin to shed their lovely long stamens in the morning, and are past their best by early afternoon.
Mature plants produce many flowers over quite a long period. In the wild, they are usually defended by large ants, who are attracted by nectar – not the nectar in the flowers, but nectar from special glands called “extra-floral nectaries”. Caper trees have evolved a special relationship with these ants, developing these extra nectaries to attract them. In return, it is the ants’ job to defend the flowers from crawling insects which would lay their eggs in the developing fruits, and devour the seeds. You will probably notice that they are only partially successful, as insect infestation of the fruits is common. Whether this has always been the case, or is a modern phenomenon, resulting from disruption of the environment, I have no idea.
It does illustrate, however, the interdependence of plants and animals in the ecology. Not only do animals (in this case the butterflies and the seed-eating insects) need plants for their survival, but the plants need Animals. These capers use both pollinating insects and the defending ants. They possibly also use animals of some kind to distribute their seeds. Birds, perhaps? Overripe fruits, if they have not succumbed to insect infestation, turn orange, which may attract birds to feed.
(See article December 4, 2008, for more on this plant)