When it comes to the issue of what Australian native food plants to place in your tropical garden, there seem to be a number of opposing considerations to mull over. Unless you're fortunate enough to have acreage at your disposal, or are planning for amenity planting in parks or educational public gardens, you are going to have to juggle limitations of space, both vertical and horizontal, and probably the availability or otherwise of water, as well as soil type and aspect. Herein lies your first dilemma.
Many of the tropical bush foods most eagerly sought after by both Aborigines and Europeans were (and are) fruits borne on trees that can grow quite large in both directions. Burdekin Plums (Pleiogynum timorense) are eaten up to the present day, both as fruit in the hand and as jam and jelly. They are easily gathered, but have to be stored to ripen and soften for eating. The old method was to bury them (tied in a sugar bag and buried in sand on the creek bank according to my Dad). I always hung them on the back verandah in mesh onion bags, as my boys were very partial to them, but now I just leave them in a paper bag in the fruit bowl on the kitchen bench. BUT, I don't have a Plum tree in my garden, handsome and shady as it is, because it is just too large. I rely on the trees in local parks.
Unfortunately, quite a number of delicious and/or interesting fruit and nut trees are impractical for the average home gardener, particularly as suburban lots get smaller. They are either too big or have very invasive roots, or both. They can, however, do very well if you have space at your disposal and if you can buy or propagate good stock. Examples include the figs such as Cluster Fig (Ficus racemosa), Rock Fig (Ficus rubiginosa) and Sandpaper Fig (Ficus opposita), often acquired as a bird spread weed. However, these random plants are rarely particularly good eating, and it is worth seeking out a superior selection like this if you're going to plant one.
They used to be commonly planted or allowed to grow in chook yards, as an economical way of stretching the feed supply. Candle Nut (Aleurites moluccana), Blue Quandong (Elaeocarpus grandis), Illawarra Plum (Podocarpus elatus), Leichhardt Tree (Nauclea orientalis) and Bottle Trees (Brachychiton australis, B.rupestris) all fall into the 'too large for a suburban block' category. There are other trees which have the potential to grow large or/and tall, but which either grow fairly slowly, or can be somewhat contained by site selection eg in the open or under other trees.
Among these are Cheesefruit or Noni (Morinda citriodora), Davidson's Plum (Davidsonia pruriens), Native Mulberry (Pipturis argenteus) and Bird's Eye or Red Jacket (Alectryon connatus or A.tomentosus). Of these, I'd pick Davidson's Plum. It bears while still very small, and the large tart fruit makes beautiful preserves and cooked desserts, not to mention very acceptable wine and liqueur. This is one of the native fruits in commercial demand. It needs to begin life in the shade, and does require extra watering, at least in the early stages. So what does that leave us? Most gardens have room for at least one specimen tree and probably you’ll want to make use of screening small trees, shrubs or hedges and maybe even topiary features or a large potted plant as a focus.
The plants that immediately spring to mind are the Backhousias and the Lillipillies. Of the Backhousias, Lemon Myrtle (Backhousia citriodora) is the best known and most popular, as well as the most commercially sought after, but Aniseed Myrtle (Anethola anisata) with its glossy green wavy edged leaves smelling of aniseed when crushed is very attractive as a screen or hedge, and also has commercial applications.
Lemon Myrtle or Lemon Ironwood is a beautiful tree. We were so sad to lose our 35 year old specimen early last year after the deluge. We thought the constant soaking rain would do it good, but after flourishing through 20 years or so of drought, it apparently succumbed to a root fungus which we were unable to arrest. It used to be a magnificent tree. It did grow considerably taller than the 15-20 feet we were quoted by the nursery when we bought it, but it did take light pruning. It had the most commercially desirable ratio of essential oils, and the dried leaves were saleable, but picking and drying them was so tedious and time consuming that after a couple of goes selling consignments to Vic Cherikoff in Sydney, even the kids wouldn't come at it any more.
I used the dried leaves in potpourri and in the linen cupboard, put fresh crushed leaves in the cold water jug or bottle, in the teapot, and sometimes in cooking rice or finely sliced in a curry. But the constant joy of the beautifully shaped tree was to see it burst into bloom in November, like a giant creamy candle, attracting birds and insects, especially myriads of Blue Triangle butterflies, while the heady scent of its honey hung heavy in the air.
Seedlings came up frequently in the garden, but attempts to transplant them were unsuccessful. I had some success leaving pots of soil under the tree so that seeds would germinate in them, but it was hit and miss affair, and I gave them all away. Currently we're trying to transplant larger seedlings and root suckers from them, but with little success. It is such a beautiful tree, and we will certainly replace it. The ones in the Kershaw Gardens Rockhampton are still going strong and it is certainly a highly desirable species with many garden applications.
There is so much choice available under the general umbrella of "Lillipillies" that the novice gardener can be excused for feeling confused. It is therefore pretty important to know both the function and the position in the garden you envisage for your plant before deciding which to choose. From one of the new cultivars such as "Tiny Trev", which makes a low edging hedge for a formal garden or a potted topiary, to the large spreading tree that Syzygium australe or S.oleosum can become, there is a lillipilly for almost every situation.
Of course, in many cases, the fruit will not be the primary reason for your choice, being more in the nature of an edible decorative bonus, but if fruit is your prime motivation, then the old standard, Syzygium luehmannii, takes a lot of beating. Small leaved lillipilly or Riberry is a nicely shaped small compact tree, with glossy green leaves and attractive pink new foliage, fluffy cream flowers and bunches of bright pink teardrop shaped fruit which taste of cinnamon and cloves. This is another fruit in commercial demand, and there are a number planted as suburban street trees in Rockhampton which seem to be doing well.
We have a Scrub Cherry, Syzygium australe, collected as a seed from Bouldercombe Gorge, growing in our front garden. Unfortunately, there is now a power line routed diagonally across our yard from the power pole out the front of our place to the house next door, and, naturally, it was slung right above our tree. Fortunately, it takes very heavy pruning, but as a result we no longer enjoy the former heavy fruit crop, and I'm not sure whether we will retain that particular tree. However, I have another from Byfield with superior fruit, growing out the back, so cutting out the one in the front and replacing it with something else, won't be a tragedy. I've made many a batch of wine and jelly from the fruit, as a seedling grown tree tends to bear a fairly high proportion of fruit containing seeds, these are the more practical uses, though I have experimented with things like muffins.
Syzygium australe is quite a variable species: it can be upright or weeping, have pointed or rounded, large or small leaves, and a single or multi trunked habit, which makes it very useful in many different situations round the yard. We also have Syzygium wilsonii growing out the back, though more for its appearance than its fruit, as it's a small weeping shrub. Its pink new foliage, deep purple-red pompom flowers and unusual white fruit are very striking particularly as it is a shade loving plant growing under larger trees, or at least among other trees for protection.
However, my favourite Lillipilly for taste is the blue Syzygium oleosum. The fruit's appearance is really pretty and unusual, and some varieties have quite large fruit. Unfortunately, it does have the potential to grow very large, so.....I don't have one in my garden, nor do I grow any of the large fruited tropical varieties such as S.forte or S.suborbiculare for the same reason, though Ralph Atcheson has quite a few in his large rainforest garden on the outskirts of town, including this Syzygium boonje.
So, let's get down to something we can manage in the average garden in the tropics: small trees, shrubs large and small, vines and creepers, and herbs, and if you're so inclined, palms and grasstrees. Some of the native citrus are worth growing. There are the new cultivars of Finger Lime, Citrus australasica, beloved by trendy restaurants, and the Mt White Lime, Citrus garrowayae, which is doing very well at the Kershaw Gardens, or if you have a dry climate garden, the desert Lime, Citrus glauca. This is very slow growing, (though grafted varieties do fruit sooner), carries thorns, and does have a tendency to sucker, so you need to consider placement carefully. However, your reward is small tart fruit that make the most delicious marmalade jam.
Decorative small trees suitable for the home garden include the Native Ebonies, Diospyros humilis and D. geminata, whose regular shape and pinky copper new foliage would be enough to secure them a place, but whose fruit is edible when fully ripe as well. Cocky Apple, Planchonia careya, is an interesting choice for a water-wise garden. The small, rather gnarled looking rough barked tree nearly always sports a few bright orange-red leaves among its large bluish-green ones, and the flowers, though short-lived, are most unusual pink and white bunches of stamens which carpet the ground under the tree. The green football shaped fruit is edible both raw and cooked. The bark was used by the Aborigines as a fish poison.
The Peanut Tree, Sterculia quadrifida, has particularly striking orange fruit, which split to reveal 2 rows of satiny black seeds with tasty edible kernels. These 3 trees, though very different in appearance from each other, are very much at home in a Japanese style garden. And while we’re on the subject of nuts, you could do worse than the old Queensland Nut or Macadamia, as long as you’re prepared for the labour of cracking the nuts when you harvest your crop.
Many Capparis species are suitable garden inclusions. A good one for the tropics is Capparis lucida. This is a large, glossy-leaved shrub, with typical white Capparis flowers and dark purple skinned fruit hanging on long stalks. The orange flesh clings to the seeds, so there's not a lot you can do with it apart from eating fresh. Many of the workers at Kershaw use it like chewing gum, holding it in the mouth as a thirst quencher, before discarding the well sucked seeds. The short-lived long-stamened white flowers are very beautiful, and the occasional defoliation by caterpillars of the Caper White butterfly is a small price to pay.
While Bottle Trees and Kurrajongs might be too large for the average house block, there is a Brachychiton that can be a real winner, especially when supplementary water is scarce. A multi-stemmed shrub, which can be very straggly if not regularly pruned, Brachychiton bidwillii has spectacular reddish flowers, followed by the typical boat-shaped seed pods. The seeds are surrounded by irritant hairs, so perhaps this isn't a good choice if there are small children in the yard. The Aborigines used to stir the seeds with hot coals in a coolamon to remove the hairs before processing into paste or flour, depending on whether the seed was fresh or dry. Early settlers used it as a coffee substitute or flour extender.
If you want a really tough small tree, that can stand salt winds and doesn't need extra water, and looks good as well, then Tuckeroo is what you're looking for. Cupaniopsis anacardioides has festoons of small golden yellow fruit which are very decorative. There is only a thin skin of highly aromatic flesh around the seed, which some people really like, but which I can quite happily live without. The tree seems quite attractive to green ants too, so you can have an extra source of bush tucker as well. Did anyone see the episode of "Food Lovers' Guide" in which the chef in Cairns used crushed green ants in the marinade for smoked fish? However, if you have a real infestation, I also have the recipe for a good bait which genuinely works.
One of the proven performers in both public and private gardens in Rocky is the Beach Cherry, Eugenia reinwardtiana. This rounded shrub with sweetly scented tiny white flowers followed by shiny round red fruit is a winner. It can be pruned and shaped, makes a great hedge, path edge, or single specimen, grows and fruits in the shade, and is quite delicious. Some of the local selections have quite large fruit in which the large, usually single seed, is replaced by up to half a dozen smaller seeds that fit snugly together like a three dimensional jigsaw puzzle. It is surprisingly hardy, and easily propagated from seed. It can edge a path, screen a fence, provide an understory, or stand alone with equal success Melastoma affine, sometimes called Bluetongue for reasons that will quickly become obvious if you eat it, is an understory shrub with an attractive pinkish-mauve flower and interesting edible, if rather gritty, fruit. It can be eaten raw when fully ripe and the skin begins to split, and I found that it can be made into syrup which is quite acceptable as an icecream topping or drink base. It's another of those handy things that will flower in semi-shade, but it does need extra water.
Millaa Millaa or Elaegnus triflora is a rather informal scrambly shrub with tiny, sweetly scented flowers and small delicious fruit, but perhaps its most striking feature is the silvery metallic underside of the leaves. These are really eye-catching when used in floral arrangements. The plant is another which needs regular pruning to keep it manageable, but is quite an asset in the garden.
The easiest of all Australian fruits to grow in a tropical garden is Rubus probus, one of the Native Raspberries. But - be careful! It spreads by root suckers, so needs to be contained in some way, either in a large container, against a wall, or surrounded by a root barrier of some sort, and it has prickles. If you have an appropriate place to plant it, you can harvest a good crop of delicious fruit from a small number of plants. Treat it just like any cultivated raspberry - ample water, fertilizer, regular pruning, a southern or eastern aspect, and you will be well rewarded. It is probably the most successful bush food grown in our garden.
And for a shrub that was not only extremely useful to the Aborigines, providing food, medicine and twine, but which will provide splashes of brilliant colour in your garden, there's Native Hibiscus. Hibiscus heterophyllus occurs in 2 colour forms with short-lived but prolific flowers of bright yellow, or shades of white, pink and maroon. Use the petals in a salad, or make jam, jelly or syrup from them, as you do with the introduced Rosella, which is also an Hibiscus. Hibiscus needs regular pruning, including tip pruning, to encourage a pleasing growth habit, as it has a tendency to grow 'leggy' and sparse if left to its own devices, but it's really worth the effort. And to fill in space lower down, what about the Trailing Hibiscus, Abelmoschus moschatus, which possesses a bright pink-red flower and an edible tuber?
Many of the food vines are too vigorous and rampart in their growth to be suitable for a smaller garden. If you plant Cheeky yam, Dioscorea bulbifera, you'll probably be sorry, though Joyce Hill has kept a vine growing on a wire cylinder in her front garden under control for more than 20 years, by snipping off every stray shoot as soon as it begins to wave around. On the other hand, it is now a major headache down at Kershaw Gardens, where the lack of staff coupled with no on-going maintenance programme allowed it to "get away" and spread indiscriminately, so that each Spring more and more vines spring up in strange places.
The native grapes have, unfortunately, done the same thing. Tetrastigma nitens, for example, is smothering trees faster than it can be removed, and some of the Cissus are not much better. Not to mention the feral Stinking Passionfruit, Passiflora foetida, whose tasty little fruits have seen it spread all over Kershaw as people spit out the remains of their little snacks.
Long Yam, Dioscorea transversa, is a much better bet for a home garden, being a slender twining climber with arrow shaped leaves, and large bunches of decorative winged seed capsules. Like all the yams, it dies back in the Dry, but will shoot again from its underground tuber.
Of the 2 'look-alikes', Eustrephus latifolius and Geitonoplesium cymosum, I'd go for the Eustrephus. Wombat Berry is less aggressive, and will withstand dryer conditions, and it looks good scrambling over a rock or cascading down a garden wall. Of course, you're unlikely to want to dig it up to eat the tuberous roots, but you can snack on the little white 'desiccated coconut' arils among the shiny black seeds inside the orange fruits.
Getting down closer to the ground, a very hardy informal groundcover or low screen is Myoporum sp. or Boobialla. Small white flowers are followed by shiny round pink-purple fruits with a salty sweet aromatic taste. The birds like them anyway, and the plant is really very useful.
The hardy and adaptable Midyim, Austromyrtus dulcis, is a similar sort of height, but with a different habit. Slender opposite leaves with coppery new growth, small white flowers and shiny white fruit speckled with purple make it a very pretty tall ground cover. As well, the soft berries are sweet and delicious. A good plant for sandy soils. Another good one for sandy or salty soil is Ruby Saltbush, Enchylaena tomentosa. Fleshy blue green leaves and tiny red or yellow fruits are edible, and it's a rather surprisingly attractive informal low rounded shrub, which has been used to great effect in the Kershaw Gardens, as has the lower growing Beach Banana or Pigface.
Carpobrotus glaucescens has bright pinkish daisy flowers followed by red fruits like a miniature salty banana. The large fleshy leaves have also been cooked and eaten. It's a tough groundcover for full sun and sandy or salty soil.
A groundcover which is probably the nearest thing Australia had to a green vegetable in the European sense is Warrigal or Botany Bay Greens or New Zealand Spinach, Tetragonia tetragonioides. I find this plant a real enigma. It grows prolifically along the Capricorn Coast and covers hectares further inland, where it can be a significant weed in broad acre farming. Everyone tells me it's tough as old boots, but I cannot keep it alive! At my place it seems to boil somehow. Perhaps it's just too humid in Rocky itself.
At the height of the severe water restrictions in the south-east corner towards the end of 2007, the only green left in the gardens of 2 of my friends in Ipswich was their Tetragonia, which they harvested leaf by leaf. It looked pretty ratty by then, but it was hanging in there. I was given a precious rooted cutting to bring home, and you guessed it! Dead within a couple of weeks. It makes me feel very inadequate, especially when I hear of people, admittedly not in Rocky, who have trouble keeping it under control and consign quantities to the compost.
Others are fortunate enough to be able to sell their excess crop to a restaurant or at a market. It's a pleasant and acceptable green veg. but you need to take care to blanche the leaves before eating.
Then, for an easy care low groundcover that flowers in the shade, you can always use Native Violets, as long as you have the water, as they need a lot. Both Viola hederacea and V.betonicifolia have edible flowers, and look good in the garden as well. The flowers can be added to salads, desserts and fruit cups, frozen in ice cubes to create a talking point at a party, or crystalised with egg whiter and caster sugar to decorate cakes. I've still got a little bit left in a jar of Violet jam from France that I was given as a gift. It's delicately flavoured and scented, and quite delicious, so I'm going to experiment with making some myself when I can find the time.
If you're lucky enough to have a garden pond, large or small, edible natives can be incorporated in your plantings in and around the water. Even the tiniest pond can support some Nardoo, the aquatic fern Marsilea, on which Burke and Wills infamously starved to death because they didn't prepare the sporocarps properly. Larger ponds may contain water lilies, with their edible seeds, stems and tubers,
Spike Rush (Eleocharis dulcis) or Water Ribbons (Triglochin procera), also with tasty edible tubers. Around the edges or in a sheltered damp spot you could grow Costus potierae with its lemony edible white flowers, or if you have plenty of room, you could try any of the other native gingers, though Alpinia can take over with very little encouragement.
Curcuma australasica is an unusual and decorative choice with its pink and green flower spike and large fluted leaf, which dies back in the Dry. Bungwall Fern (Blechnum indicum) is another possibility for a damp spot, but again, is probably better contained in some way, as its underground rhizomes are very vigorous. Then as a landscaping statement, you may wish to incorporate some plants with strappy or spiky leaves as contrasts to the rest of your plantings.
Lomandra and Dianella immediately come to mind: the shiny blue Dianella fruit is best either eaten fresh or made into jelly, because of its single hard seed. Finally, there are the interesting bits and pieces which, while edible, you probably wouldn't actually consider utilising for food.
Grass trees, Cabbage Palms, Cycads, Orchids and some Lilies make interesting garden subjects, and of course there are all the colourful nectar bearing varieties such as Banksia and Grevillea, and the seed producing Wattles. This one is an unknown quantity. I don't know of it being grown in anyone's garden, but we've raised some plants from seed down at Kershaw. It's Gardenia edulis or Breadfruit, one of the ones Leichhardt ate on his trek north (but not the Breadfruit of the Lynd, though it has been mis-identified as such. That is Gardenia wilhelmii, and I have 2 precious little plants alive at Kershaw). In the wild Breadfruit is a small, rather gnarled looking tree. I haven't seen the flowers. It will be interesting to see how it performs.
Advice on incorporating bush food plants into your garden is no different from the advice given to anyone planting a garden. Plan your garden first. Know where each plant will be positioned and what you expect of it. Water, mulch, fertilise and prune as you would for any garden plant, remembering to use a low phosphate formula for Proteaceae.
Lenore is Co-ordinator of the Australian Food Plant Study Group