Northland
Two tropical trees that are pretty in pink win Wendy Laurenson’s heart.
The silk floss tree ( Ceiba speciosa) celebrates summer with a spectacular show of hibiscus-sized pink flowers that obscure most of the leaves and can decorate the tree for weeks. The pink flower petals fade into cream centres punctuated with dark speckles, and their nectar is a magnet for monarch butterflies.
However, this beauty has a beast to protect it. Vicious cone-shaped thorns cover the trunk and are a standout feature of the tree. These are more prevalent on the lower part of the trunk and look like they have evolved to deter predators from climbing or rubbing against the tree.
The name silk floss refers to the fluffy infill fibres of the tree’s seedpods that are very apparent in its South American homeland. These white fibres also give the tree its common name of Brazilian kapok tree, and while it was never the main source of kapok (which comes from Ceiba pentandra), the fibres were traditionally used for stuffing mattresses, life jackets and pillows.
The seedpods are not common here because the gorgeous flowers are not selffertile, and this is the first year I’ve seen one ( just one) on a local silk floss tree. While their nectar is enticing to our bees, the flowers’ sexual parts are too deep for them to reach and we don’t have the hummingbirds and tropical insects that pollinate them in their homeland. However, monarch butterflies are drawn to the flowers and there is speculation that their long coiled tongue may be able to pollinate the flowers.
To allay fears of a wind dispersal of the masses of seed-carrying white fibres, the seeds embedded in the fibres are big and don’t fly far, so any seedlings would come up close to the tree.
Despite its tropical origin, it is deciduous and can withstand light frosts. It can also cope with drought, wind and coastal conditions, and grows very big very quickly, even in our Northland conditions (the trunk base is thick and bulbous, and when the tree is young its bark is green so the extra chlorophyll further fuels growth).
Silk floss trees can reach 25m in their homeland; even here, it will reach over 8m so this spectacular beauty needs a big space to show off its pink-flowered cloak. The tropical Queensland lace bark ( Brachychiton discolor) also covers itself in pink flowers in summer. Its growth habit and identity baffled me when I first met it though. It is a handsome tree with generous leaves similar to the deciduous tulip tree ( Liriodendron tulipifera), but unlike the tulip tree, it defied the leaf-drop timing cue and wore its green cloak all winter.
In a surprise move, the lace bark then suddenly dropped its leaves in midsummer.
This prompted me to be concerned for its welfare – but not for long. It soon punctuated its naked branches with masses of waxy tubular pink flowers that eventually enabled me to identify it.
Lace barks are a medium size tree native to the tropical dry forests of northeastern New South Wales and Queensland where they drop their leaves in summer then produce their waxy pink bell flowers. When the flowers fade, the foliage returns.
These trees belong to a plant category known as summer (or dry season) deciduous, meaning they have evolved to briefly drop their leaves during the hot dry conditions to conserve water. They are therefore drought tolerant, cope with most soils and are happiest in full sun.
The leaf drop timing can vary according to the season and sometimes leaves remain on part or all of the tree all year.
The lace bark tree is one of dozens of brachychiton species, most of which originate from Australia. In their homeland, lace barks set seed in long pods but I haven’t yet seen any on our local tree.
The discolor in their name refers to the leaves being dark on the top and light on the underside, and lace bark describes markings on the bark as the tree matures.
A better known member of this family, and one that is often seen here in the north, is the spectacular Illawarra flame tree
( Brachychiton acerifolius) which also sometimes sheds its leaves briefly in summer only to then explode into its mass of fiery scarlet flowers.
Both of these brachychiton beauties grow into substantial trees so need plenty of room in a warm sheltered spot to show us their floriferous treasure and surprise us with their leaf-drop tricks.