The iconic Illawarra Flame Tree (Brachychiton acerifolius) flowered abundantly this year, lighting up everywhere from the escarpment to Lawrence Hargrave Drive.

“Flame trees are really spectacular in the urban areas when they’re flowering,” says local expert Leon Fuller, author of the bestselling book Wollongong’s Native Trees.

“They are endemic to Australia and indigenous to the Illawarra, but they occur from around the Shoalhaven River all the way up to Cape York.”

Irregular flowering

Flame trees usually flower in late spring and early summer, alongside other vibrant trees such as the purple Jacaranda and yellow Silky Oaks. They are often mistaken for coral trees, which display red flowers in our winter and are not native to Australia.

“What’s interesting about Flame Trees is that the flowering stems are red as well as the flower,” Leon says.

“That’s what gives us a whole heap of that bright colour we see. When they’re finished flowering, the stems drop off and [the trees] go back to green.”

While we’ve enjoyed a spectacular flowering season this spring in the Illawarra, Leon says that Flame Trees tend to flower differently every year.

“If planted as a seedling, it will take at least seven years for the tree to flower for the first time, sometimes even 15 years, and after that they’re quite erratic,” Leon says.

“They won’t flower every year. And when they do, it is irregular. Even this year, there are some that are still flowering with flowers on one side and leaves on the other. Some years they’ll flower with just a bunch of flowers and lose all their leaves.

“It’s variable. The reasons for that irregularity are not well known.”

Leon says Dr Kevin Mills’ monthly plant journal recently speculated that Flame Trees might flower better after a dry winter.

Adapting to conditions

The Illawarra Flame Tree is known for its striking red flowers, but Leon says the leaves are particularly interesting. Flame Trees have a characteristic called heterophylly.

"There's a whole story in the names of plants," Leon says.

This term refers to the tree's ability to produce different types of leaves throughout its life cycle.

"When it is young and the tree is trying to establish itself in the plant community, the leaves need more surface area to catch light and make sugars to grow,” Leon says.

“When it gets old and grows to the top of the canopy, there is more light up there and a smaller leaf will catch the same amount of light.”

Natural habitat and growth

Despite thriving in urban settings, the Flame Tree is naturally a rainforest species.

“Ecologically, they are rainforest trees, so they grow best in a rainforest,” Leon says.

In a rainforest, the trees can grow up to about 30 metres.

“But most of the plants in a rainforest community grow very well under normal garden conditions. People water their gardens and care for the soil – [Flame Trees] love it,” Leon says.

In urban areas, a Flame Tree might grow to be between eight to 15 metres tall.

“The only thing people might not always do is leave enough room for a Flame Tree,” Leon says.

Ecological significance

Various wildlife species eat the fruit of the Flame Tree, which emerges after the flowering season. The large, boat-shaped pods are difficult to break open but accessible to larger birds such as cockatoos, currawongs, the southern bower bird and the king parrot.

“People can eat the fruit too,” Leon says.

“They can even make a coffee substitute with it. But the danger with it is that amongst the fruit, there are little fibres that you need to clean out.”

These fibres will irritate the skin, nose and throat if inhaled.

To buy Leon's book visit Collins Booksellers Thirroul and to find out more about the region's plants, visit the Growing Illawarra Natives website.