Native Tamarind (Diploglottis australis) Growing Guide

What is Native Tamarind?

Native tamarind is a prized Australian tree known for its fruit. The taste can be likened to its namesake Asian tamarind although they derive from different families.

Its botanical name Diploglottis australis comes from the Greek ‘diplos’ meaning double and ‘glotta’ the tongue, referring to its cream flowers showing two tongue-like glands at the base of each petal.

The large leathery leaves of native tamarind are striking and instantly recognisable. Their pinnate leaf structure, possibly an adaptation of rainforest conditions and dappled light, stands out amongst the flora, with newer leaves being covered in a velvety brown and bronze fuzz almost resembling kangaroo paw plants. 

These large leaves can even reach 60cm in length and are among the largest leaves in the Australian rainforest. The veining almost makes the more mature leaves of the native tamarind look crimped. 

What is Native Tamarind’s Natural Habitat?

Diploglottis australis is native to temperate and sub-tropical regions across the eastern coast and northwards towards Proserpine and tropical Queensland.

It can reach up to 30 metres tall within the rainforest but only about 10m in domestic gardens, where it typically has a more open space, and less need to grow competitively against other taller trees.

Edible Uses & Identifying Native Tamarind

The native tamarind is actually a relative of the lychee, and they do produce a fruit that is edible and is noted to have a pleasantly acidic and tart, refreshing flavour. 

If foraging, the brown fruits are the bush tucker target. They develop in dense clusters, with unripe fruits appearing bright orange, on pale brown stems. Elongated but curled rippling foliage grows in opposite pairs along stems, often as multi-stemmed trees with smooth white bark.

The brownish-yellow fruits can be eaten raw or made into jam and juices. These berries are double or triple-lobed and appropriately 3cm in diameter, similar to a small fig. Inside the hairy light brown casing is a juicy orange pulp called aril which is jelly-like in texture. 

As well as having useful timber for firewood and construction, an important horticultural use for the Diploglottis australis is for shade as its dense canopy of leaves can cast a wide shady area beneath.

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How to Grow Native Tamarind

Growing native tamarind is about as straightforward as it gets with native trees. There are no reports of this tree being invasive, but it does fruit and seed prolifically as it is hermaphroditic (flowers possess male and female parts).

So plant responsibly, and if you are aware of any conservation efforts for the threatened Diploglottis campbellii near you, consider planting alternatives.

Best Conditions for Growing Diploglottis australis

Filter sunlight is the preferred position if we’re talking about recreating nature, but for a more open canopy, native tamarind can be planted quite happily in full sun, or a more open garden setting, where it can form a neater, more stable canopy that the taller trees we’re more used to seeing in forest settings.

Soil & Drainage

Once established, Diploglottis australis can tolerate drought, but immature trees will need moisture-retentive soil. During the drier periods, native tamarind often drops its leaves to conserve water and reduce any transpiration, this is a natural adaptation of the tree. 

However, you can keep your tamarind lush and leafy by maintaining a good watering schedule. 

Light & Temperature

Diploglottis prefers filtered sunlight but they will tolerate full sun. Native tamarind would prefer dappled light and to be part of a community of trees if you can provide it, and it provides an excellent screening tree when planted as part of a dense mixed hedge for that reason. 

Once mature the Diploglottis will withstand harsher conditions and lower temperatures, but young trees should be protected from frost.

Shelter

Doploglottis australis is best placed in a sheltered position protected from harsh winds. These trees are happiest in a rainforest situation with the support and shelter from surrounding trees, offering them a windbreak from the strongest winds. 

Planting Native Tamarind

Native tamarinds are quite tolerant of urban situations so can be grown happily within a garden design. However, as mentioned above, they do require some protection from strong winds, especially when young.

Plant them into a hole twice the width of the root ball, and an inch deeper. Position your tree in the planting hole, then backfill with a good soil mix with reasonable moisture retention. Heel it in very well, and soak the root ball after planting.

Finally, mulch over the watered ground to lock in moisture, and add a tree stake at 45 degrees, pointed into the prevailing wind.

How to Propagate Native Tamarind

Native tamarind can be propagated from both seeds and cuttings. Seeds are generally considered to be more successful, but cuttings, if taken quickly before they dry out, do have a good success rate.

Instructions for both propagation methods are outlined below.

Propagating Diploglottis australis from Seeds

The most effective propagation of native tamarind is from seed. Use fresh seed from the centre of the fruit and soak it in water overnight. The seeds should germinate fairly reliably, usually within a fortnight, but it can take up to two months.

Once germinated, they will produce small seedlings covered in a protective layer of fuzz. The seedlings are slow to grow at first, but suddenly develop following a month of seemingly no growth at all. 

When this starts, check the roots regularly, and pot on when they begin to wind around the pot, but before they are root bound.

Propagating Native Tamarind from Cuttings

In the warm season, when you know the weather will not drop below 15°C for at least the next three weeks, take semi-hardwood cuttings about 10cm long, including a node at the base.

Dip the cut point in rooting gel as soon as possible, and plant it straight into a mix of coir, peat-free compost and perlite (any or all of those will work). 

Leave the cuttings somewhere warm but shaded, watering if the potting medium dries out. Cover the cuttings with plastic bags, or place them in a cool cold frame. Rooting can take time, but it should start to root within a month, and new growth should be visible after that.

How to Care for Native Tamarind

Native tamarind can also be grown as a happy indoor houseplant. Positioned by a bright window where it can get good indirect light, tamarind can be cut back and trimmed to keep it small and will provide you with spectacularly stunning indoor foliage. 

Diploglottis australis would benefit from an occasional fertiliser as a houseplant and some occasional visits outside where it can soak up some rainfall. Infrequent misting with tap water will keep the humidity just right too.

It doesn’t need to be routine, but on warmer, drier days, it will give it a much-needed boost. 

Pruning Large Leaf Tamarind

Native tamarind is very amenable to pruning. Not only does it not mind when it is pruned, but it also seems to be quite happy with being pruned in any way you see fit. Cut it back hard, or remove half its canopy; pinch out growing tips, or cut out canker.

Whatever treatment they get, these trees just keep on coming. So whether it's for the health of the tree or just for aesthetics, you should routinely remove dead, diseased or dying branches. Native tamarind will respond and adapt. 

Native Tamarind Busk Tucker Guide

Diploglottis australis takes upwards of 5 years to reach fruiting maturity, but once your tree fruits, it will be prolific every year from then on. Each year, more laden than the last, with small berries that will fall off the tree once ripe.

The berries are ripe as soon as they come away easily, with a rock backward or gentle tug. Time is of the essence when harvesting as the fruits are highly attractive to birds, bats and any other passing opportunist looking for a juicy treat.

How to Store Native Tamarind

The easiest way to use native tamarind is to simmer it down and soften the fruits to mix through other food as a flavouring, but it can be eaten raw. In both cases, it can be quite astringent.

Its unique earthy bitterness works best in jams and chutneys, where it adds a bitter kick but with depth. And by preserving it in this way it can last for several years in a cool dry cupboard.

Common Native Tamarind Pests and Diseases

Other than scale, aphids and caterpillars, native tamarind is pretty impervious to garden pests. Its main issues come from disease, which in our experience is most commonly caused by poor planting location.

Essentially, the most common explanation for planting conditions with Diploglottis is ‘moisture loving’, but that doesn’t mean it wants to be wet all the time. This can cause root rot, leaf burn, leaf drop, and all sorts of related issues that will, at first, appear like signs of underwatering or drought. 

If you notice any of these symptoms, particularly on young trees, check the soil before doing anything else. If it's wet, but the tree looks dry, let it dry out completely before doing anything else.

If the soil is dry, leaf scorch and drought can be damaging to young trees too. The biggest sign will always be the soil, rather than the tree itself.

Native Tamarind Frequently Asked Questions

Can you eat native tamarind?

You can eat native tamarind raw or cooked, and while its flavour is quite astringent, it has a depth to it that is really unique and incredibly interesting. It's worth growing as a plant for wildlife, but definitely worth trying yourself too.

How big are native tamarind trees?

Native tamarind trees grow up to 35m tall, but rarely grow more than 10m in garden settings. They are wonderful garden trees, adding shade and character without the risk of a 90ft monster tree taking over your yard.

Does native tamarind have invasive roots?

Native tamarind (Diploglottis australis) does not have invasive roots. They are shallow and rarely grow out beyond the width of the tree’s canopy.

Is native tamarind safe for dogs?

Native tamarind is not safe for dogs. If you have dogs, they should not be allowed near the tree when the fruit is nearly ripe as ingesting any amount can cause severe gastrointestinal upset.

What is the lifespan of Diploglottis australis?

Diplglottis australis is a long-lived perennial tree. These trees are native, rainforest-loving plants that will easily outlive most who plant them, ensuring a gorgeous and dramatic legacy in any garden.

Is native tamarind invasive?

Native tamarind is not reported as invasive, and its seeds rarely germinate outside rainforest settings, but it is still worth being vigilant about seed capsules that do drop, and weeding out seedlings as they come up.

Is native tamarind evergreen?

Native tamarind is a dramatic evergreen tree, growing to a maximum of 35m tall. Its foliage remains on the tree right through winter and is replaced by new growth each spring.