Bolwarra (Part 17)

Eupomatia laurina [bolwarra foliage] sml.jpg

Bolwarra, Eupomatia laurina, in Mt. Annan Botanical Garden, Camden. © JPM, 2022.

A throwback to Gondwana, apparently! Do you dare to eat these ancient, fragrant fruits?

Names

Hailing from the ancient plant genus Eupomatia (E.), these relics of a lost world are still happy to call Australia and Papua New Guinea home. All Australian species commonly go by a First Nations monniker, bolwarra, and this is their most common name. There are three species of bolwarra known on this continent: E. laurina, otherwise known as the copper laurel; E. bennettii, the small bolwarra; and the rare E. barbata, the northern bolwarra. All species may also be referred to as the native guava, to which they are very distantly related.

Habitat and Range

Bolwarra is a rainforest understorey plant, occurring in its native range amidst the humid east coast climes. Bolwarra prefers rich, moist, semi- or completely shaded areas with constant humidity and does not tolerate winter frosts or open, dry, windy areas of the interior. It will happily grow in mountainous regions up to 1,300m elevation, such as in Papua New Guinea. The larger and more prolific bolwarra, or copper laurel, E. laurina, can be found in tropical, subtropical and temperate valleys, either rainforest or wet sclerophyll (eucalyptus), the length of the east coast from south-east Queensland to the eastern corner of Victoria. The small bolwarra, E. bennetti, is found south of Fraser Island in south-east Queensland and northern New South Wales, as far south as the Nambucca river, but especially in the Gold Coast and Coffs Harbour hinterland regions; it prefers wet eucalyptus forests. The Northern bolwarra is relatively rare in the wild. Its native range exists in the hinterland rainforests between Ingham and Cooktown and the Cairns region between; it is easily missed due to its short stature.

Figure 1. Distribution of Eupomatia (all species) across the continent. Atlas of Living Australia.
Eupomatia distribution map.png


Identification

Bolwarra is a woody, understorey plant. E. laurina is the largest, usually standing between 3-5 m in height in the wild, but some old specimens have been recorded exceeding 15 m. The small bolwarra and northern bolwarra are shrubs, rarely exceeding 1 m in height. They propagate readily from seed, with germination rates often exceeding 70-80%. They cannot be propagated from cuttings.

Branches are typically gangly 'zig-zag' stems with long, glossy, veinous, alternating lance-tip leaves between 5-20 cm in length (see header image at top of article for E. laurina, and figures 2-4 below). Older branches may exhibit green-brown stripes (figure 6).

Flowers emerge along the stem (E. laurina, E. barbata) or at the growing tips (E. bennettii) and resemble small green pods until they split open, revealing their delightful cream-white flowers with pink-red anthers (figures 2, 4-5).

Flowers are pollinated by a species of weevil (Elleschodes spp., see figure 5) and set into small,1-4 cm, green, urn-shaped fruits (figures 3, 6-7). E. laurina has the largest fruit of all the species. Fruit turn yellow-brown and emit a strong smell when fully ripe, often tumbling from the tree onto the ground where they are devoured by scrub turkeys, cassowaries, wallabies and feral pigs. The fruits are similar to guava, being filled with a cream-brown jelly-like flesh dotted with dozens of hard, inedible seeds (figures 8-9).

Figure 2. Small bolwarra (E. bennettii) leaves and flowers. Atlas of Living Australia.
Eupomatia bennettii [small bolwarra - flowers and foliage - ATLAS].jpeg


Figure 3. Northern bolwarra (E. barbata) displaying its long, glossy leaves, zig-zag stem and a single unripe fruit, centre. Atlas of Living Australia. © Kerry Coleman, 2010.
Eupomatia barbata [Cooktown bolwarra - foliage and fruit - ATLAS - Kerry Coleman 2010].jpeg


Figure 4. Bolwarra (E. laurina) foliage, buds and flowers. Wikimedia Commons.
Eupomatia laurina [flowers and foliage - wikicommons].jpg


Figure 5. Opening flower of E. laurina with pollinator weevils (Elleschodes spp.). Wikipedia. © P. Woodard, 2020.
Eupomatia laurina [Flower & Elleschodes - P. Woodard, 2020].jpg


Figure 6. Unripe bolwarra fruit (E. laurina). This fruit specimen was approximately 4 cm in diameter. Mt. Annan Botanical Gardens. © JPM, 2022.
Eupomatia laurina [bolwarra fruit] sml.jpg


Figure 7. Ripe small bolwarra (E. bennettii) fruit. Atlas of Living Australia. © G. Tasney, 2021.
Eupomatia bennettii [small bolwarra fruit, ATLAS, G. Tasney 2021].jpeg


Figure 8. Halved ripe bolwarra (E. laurina) fruit. © fruitwarehouse.blogspot.com, 2012.
Eupomatia laurina [cut fruit - fruitwarehouse.blogspot.com 2012].jpg


Figure 9. Halved small bolwarra (E. bennettii) fruit. This one looks like it was picked early, i.e. unripe. Flickr.
Eupomatia bennettii [small bolwarra - halved fruit - flickr].jpg


Uses

Bolwarra fruit can be enjoyed fresh as soon as they turn yellow-brown and begin to emit their pungent, ripe aroma. The seeds are, like guava, inedible and should be discarded (or, better, germinated). Due to the strong fragrance of the ripe fruit, bolwarra has a niche use as a fruit-spice for various culinary preparations. Ripe bolwarra fruits will readily impart their unique fragrance to drinks, sauces, jams, jellies, pastries and curries. Fruit flesh can also be extracted, separated from the seeds, mashed into a paste and then sun-dried and powdered as a unique Australian kitchen spice.

The long, fibrous outer bark of larger bolwarra trees was also traditionally used as cordage for fishing nets by many First Nation tribes.

It would be a delight to see bolwarra sitting in spice racks here and internationally. All that is lacking is a brave entrepreneur willing to develop a commercial crop for spice production.