Every winter I am always impressed by the brilliant splashes of golden yellow which the Kapok Tree gives to the otherwise drab hillsides and eucalypt woodlands. While plant enthusiasts admire and plant this handsome and unusual tree, others dismiss it with a wave of the hand and say, "Oh, that's just an introduced weed".
In Australia there are two true native Kapoks. There is our local species and another which looks almost identical (except for leaf shape), which is very common in Kakadu National Park and is called Cochlospermum fraseri. The native Silk Cotton Tree (Bombax ceiba) is also sometimes known as Red Kapok, although this has red, rather than yellow flowers.
The species most commonly confused in nurseries is the central American Kapok (Ceiba pentandra). When young, they look very similar in leaf shape, but as they mature, they become very different. While our native Kapok would rarely reach more than 15-20 metres in height, the exotic Kapok can grow to 40 metres and has dull white flowers instead of the yellow of our glorious native species. It is rarely grown intentionally, since it is known to cause hayfever and asthma.
Usually found on rocky slopes and vine thicket gullies (around Townsville and further north into the Northern Territory)), the Kapok loses all its leaves before flowering, which makes the flowering more obvious. The flowers are edible raw and are quite pleasant. They are mucilaginous and slimy to chew on and I can't help but compare them to Marshmallow every time I eat them. Although more than 90% water, they are surprisingly high in Vitamin C! The tap root of young plants is also edible when roasted and has moderate levels of most nutrients. The same is true of the Northern Territory species, whose root is also pounded and used extensively as medicine for sores.
After the yellow flowers are pollinated, large, globular, green, papery fruit develop, which eventually turn brown and split along the seams to release their seed. The small black seeds are woven in a dense mat of fine silky hairs. This material is known as 'kapok' and was apparently used to stuff life preservers during the Second World War, although confusion exists as to whether the native or exotic species was used.
Kapok has also been used as stuffing in pillows, although extreme care should be taken if you smoke in bed. The Kapok fibres are highly flammable and almost explode in flame if a lit match is applied. For this reason, it is apparently good tinder to use when starting fires by friction with two sticks.
The unusual form and deciduous nature of the native Kapok deters some gardeners from including it in their collection. However, for those with rocky hill slopes and rock gardens (e.g. Castle Hill, Townsville), it would be difficult to find another tree species more suited.
(Reprinted from "The Native Gardener", newsletter of SGAP Townsville Branch, September 1998)