Wattles

Acacia species.

Ah, the inspiration for the green and gold! But do you know which parts are edible?

Names

Australia's national flower is well known and gives many of our national sporting teams their poignant colours. Known colloquially as the wattle, sometimes acacia, all of these plants come from the genus of the same name, Acacia, a plant family found widely across Africa, Asia, Australia and southern America. Oz is home to more than 600 native species, of which at least 40 prolific varieties are known to have edible properties. The most common of these edibles, as cited by Tim Low, are the east coast wattles (A. longifolia and A. sophorae), the arid interior's common mulga (A. aneura), the dogwood (A. coriacea), northern and central Australia's common wattle (A. cowleana), central and southern Australia's unnamed arid wattle (A. dichtyophleba), the strap wattle (A. holosericea), the witchetty bush (A. kempeana) and the bramble wattle (A. victoriae). To Tim's list I will add two very unique WA species: the red-eye wattle (A. cyclops) and the raspberry jam wattle (A. acuminata). A list of known edible species is included here [LINK]; however, there may remain many unknown edible species and several of the species listed as inedible in that list are marked edible elsewhere, so there is some confusion as to which is which. Notable toxic species to be avoided will also get a special mention in the final caution below.

Habitat and Range

Acacia is Australia's second-most abundant tree, behind Eucalyptus, occupying an estimated 980,000 square kilometres (378,000 sq. mi.) of land area! A native acacia exists for every possible climate, topography and range represented in Australia, primarily because of their ability to fix nitrogen from the air for use in Australia's often nitrogen-deficient soils. Wattles will live happily behind beach-fronts, in grasslands and fields of the inland plains (especially the West-Australian wheat belt), atop windy escarpments and coastal cliffs, and are probably the most prolific species of plant in the red centre. Wherever you go in Australia, you can be almost guaranteed to find an edible species of Acacia growing there, especially in the mulga-abundant arid regions of the interior.

Figure 1. Distribution of Acacia (all species) across the continent. Atlas of Living Australia. Finding an edible species is a little more difficult!

Identification

While it is certainly not difficult to identify native acacias generally, especially during flowering season in July-October, not every species is equally palatable, and some species are toxic. The poisonous species will be explored below, but there is no universal rule to distinguish which is which other than specific knowledge of the common acacia species growing in your specific region. If in doubt, leave it out!

Figure 2. The common mulga (A. aneura), which grows across the entire inland regions of Australia. Wikimedia Commons.

Native acacias are generally a shrubby tree (figure 2 above), with established specimens ranging from 1.5 to 10m in height, depending on the species and habitat. Their two tell-tale features are their fluffy yellow-white puffs of aromatically scented flowers which appear in winter and spring (June-October), depending on the species, and the fact that most Australian acacias usually have no true leaves but "phyllodes", which are flattened, leaf-like extensions of the branch. Some acacias, such as the inedible silver wattle, do display their true leaves, pictured below (figure 9). Bark can be rough or smooth, depending on the species and age of the tree, but is generally tough and, if cut, will ooze a sticky sap which crystalises red or yellow depending on the species.

Figure 3. Common mulga foliage and flowers. Wikimedia Commons.

Figure 4. Coast wattle (A. longifolia) foliage and flowers. Wikimedia Commons.

Figure 5. Witchetty bush (A. kempeana) foliage and flowers. This plant is also home to the famed witchetty grub. Wikimedia Commons.

Figure 6. Strap wattle (A. holosericea) flowers, foliage and green, unripe pods. Wikimedia Commons.

Figure 7. Bramble wattle (A. victoriae). Branch with foliage, thorns and a ripe pod. Wikimedia Commons.

Figure 8. Dogwood (A. coriacea), foliage and flowers. Wikimedia Commons.

Figure 9. The inedible silver wattle (A. dealbata), displaying true leaves rather than phyllodes. Wikimedia Commons.

Flowers give way to clusters of curled, green, bean-like pods which turn brown, dry out and crack open when fully ripe, revealing 2-20 hard black seeds which will often scatter all over the ground underneath the tree. Acacia trees laden with ripe seed pods can appear "dead" from a distance due to the dominating brown colour. However, closer inspection reveals a multitude of pods bearing seed. The seeds often have a white, orange or red funicle, a kind of stem which connects the seed to the pod. This latter feature is especially prominent in the aptly-named West Australian red-eyed wattle seeds. Unripe, green seeds typically have pale funicles attaching each seed to the pod interior (see figure 15 below).

Figure 10. Toxic and inedible hakea wattle (A. hakeiodes), laden with ripe pods. New England National Park, NSW. © JPM, 2022.

Figure 11. Close up of inedible hakea wattle pods. New England National Park, NSW. © JPM, 2022.

Figure 12. Ripe pods of the edible strap wattle (A. holosericea), also exhibiting seeds. The Forts, Magnetic Island. © JPM, 2022.

Figure 13. Closeup of seeds of the strap wattle (A. holosericea), displaying a prominent orange funicle. The Forts, Magnetic Island. © JPM, 2022.

Figure 14. Unripe, green pods of the green coast wattle (A. sophorae). South Head, Sydney Harbour. © JPM, 2022.

Figure 15. Closeup of an opened, green seed pod of the green coast wattle (A. sophorae). South Head, Sydney Harbour. © JPM, 2022.

Figure 16. Dogwood (A. coriacea), ripe seed pods with seeds. Note the orange funicle on each seed. Wikimedia Commons.

Figure 17. Red-eye wattle (A. cyclops). These seeds have a very prominent funicle, which can be a dark red colour on some specimens. Wikimedia Commons.

Figure 18. Green, unripe pods on the bramble wattle, A. victoriae. Wikimedia Commons.

Culinary Uses

Wattleseed is one of Australia's native food success stories and is an international export for which demand far exceeds supply. Having been eaten by First Nation tribes for thousands of years, many decades of research has gone into understanding its use as potential food staples in other dry climates, such as arid Africa, although caution must be shown before introducing native Australian plants to other continents lest they take on invasive weed status themselves. Seeds from edible varieties are easy to harvest: one simply grabs handfuls of the ripe, brown pods and puts them in a bag or basket (keeping an eye out for spiders and ticks!) and then you shake or beat the seeds out of the pods and sieve the seeds from any leftover chaff. Acacias will drop huge amounts of seed, so it is also possible to collect and sieve from the ground beneath the plants even if the seeds are 15-20 years old - a drought staple. Try to avoid damaging or losing the funicles during harvest - this part of the seed has most of the protein in it! Ripe seeds should be roasted well (approx 25 mins at 180°C or they will burn) prior to consumption. They can be ground into flour or paste and used in baking, pastry, icecream and other desserts, and as a coffee-hazelnut-chocolate substitute for making beverages. The exquisite, nutty flavour is a favourite of connoisseurs worldwide and a unique culinary taste and lingers on the palate for some time (10-20 minutes) after consumption.

Figure 19. Harvested seeds from three different varieties of wattle, with their pods for future identification. © JPM, 2022.

Figure 20. Pumpkin, dandelion and wattleseed (A. floribunda) soup. © JPM, 2022.

Figure 21. Approximately 10 minutes harvesting and 1 hour of sifting resulted in 84 grams of hakea wattleseed (A hakeoides). Note the small white funicle on this variety. © JPM, 2022.

Figure 22. That same 84 grams of seed rough-ground into a flour in a mortar and pestle. Use a hand or machine mill! Please note, I do not recommend making flour at all from hakea wattle, it is toxic (more on that below)! © JPM, 2022.

Green seeds can also be eaten if the unripe, green pods from edible species, especially the coastal wattle (A. sophorae), are harvested and roasted whole, and the green seeds removed for consumption. The pods themselves are inedible and should be discarded. Roasted green seeds taste faintly like peas, followed by a milder, distinct nutty wattleseed flavour that lingers on the palate for some time afterwards.

Figure 23. Oven roasted  green seeds and pods (180°C for 25 mins) of coast wattle (A. sophorae - the same pods as in figures 14 & 15 above). I prefer the ripe seeds, above, which have a much nuttier and more pronounced flavour, but these are likewise delicious. Harvested from South Head, Sydney Harbour. © JPM, 2022.

Some varieties of wattles also have edible sap/gum, also known as gum arabic in the middle east and north Africa. You want to look for dried sap which has oozed from a wound in the tree, deliberate or otherwise, which is a light golden colour. Generally, the darker the sap, the more likely it is to taste bitter or be toxic. The one major exception to this is the West Australian raspberry jam variety (A. acuminata). Its dark red and viscous sap has a tart, raspberry-like flavour, hence the name. Generally, if a species has edible seed, it will have edible gum, but this is by no means a fixed rule. Two fail-safe species for gum harvest are the common mulga, A. aneura, and the Sydney region's green wattle (A. decurrens). The southern swamp wattle, A. retinodes, has edible gum but inedible seeds. I would always advise consulting with local lorekeepers for precise identification of edible acacia gums before attempting consumption. Gums can be used as natural thickeners, stabilisers and may be dissolved in hot water as a drink. Middle-eastern Acacia gums (gum arabic) have proven prebiotic qualities, being fermented by beneficial bacteria in the colon, but these properties may not have been properly researched for Australian acacias.

Figure 24. The golden wattle (A. pycnantha), common in Victoria, has edible gum. Wikimedia Commons.

The common mulga (A. aneura) of the arid regions is also worth checking for "mulga apples." These are marble-sized bumps left on the flower buds by gall wasp larvae, and should be distinguished from other gall injuries on acacia stems, leaves and pods by the fact that the gall "apple" itself is always covered with warty bumps. They are chewy and should taste something like a dried apple. The wasp grub may or may not still be inside.

Figure 25. "Apples" on a golden wattle (A. pycnantha). Proper "mulga apples" will look very similar to these, but on the variety A. aneura growing in the red centre. Wikimedia Commons.

Other species are reported as having edible inner bark and roots, but I cannot verify these at this time, and it is more likely that these parts of the plant were used for medicinal preparations. Some species, like A. pycnantha, have extremely high levels of tannins in the bark, which can be used for medicinal purposes.

Caution!!!

Due to their ability to fix nitrogen for plant use, acacias can have some quite nasty, even potentially fatal, toxins (e.g. sodium fluoroacetate). However, one would need to eat a fairly significant quantity of raw, uncooked seed (green or ripe) or gum to be at significant risk of major ill effects, even from toxic species. When sampling wattleseed or gum in your area, always roast the seed before attempting to eat it and deploy the taste test guide outlined in the introduction to this series to assess edibility. If seed or gum tastes exceedingly bitter, causes immediate stomach upset or diarrhea, stop eating it!

As noted in figures 21 and 22 above, I harvested in New England what turned out to be the toxic hakea wattle, A. hakeoides. Desiring to be adventurous and try it anyway, I ground the seeds in a mortar and pestle, mixed it with water into a cake and baked it at 180 degrees C for approximately 30 minutes. I tried about a thumbnail portion. It wasn't terribly appealing, although the smell of the roasted wattleseed was impressive. These seeds caused a slight burning sensation to the back of the throat when eaten, and churned in my stomach for some hours before resulting in a very mild case of diarrhea. So while I definitely concluded that this variety is not worth going back for, I am living proof that, though toxic, if consumed in very small amounts and always following your sense of taste as a guide, eating a poisonous species of acacia will not result in instantaneous death.

Listed below are some of the more common poisonous species. Please click the links for additional identifying photographs and distribution courteousy of Atlas of Living Australia.

Acacia ammobia

Acacia cupularis (in older works A. bivenosa subspecies wayi)

Acacia concurrens

Acacia crassicarpa

Acacia dealbata

Acacia falcata

Acacia hakeoides

Acacia hemignosta

Acacia hubbardiana

Acacia melanoxylon

Acacia papyrocarpa

Acacia podalyriaefolia

Acacia retinodes (but edible gum)

Acacia saligna

Acacia suaveolens

Acacia torulosa

Acacia ulicifolia

Vachellia (formerly Acacia) ditricha