August 2007 Plant Highlight: Brachychiton discolor

Image of B. discolor

Brachychiton is a genus of Australian trees, several of which are featured in the plantings at the Ruth Bancroft Garden.  One of these is Brachychiton discolor, a tree with maple-like palmate leaves and fuzzy pink flowers.

Brachychitons belong to the family Sterculiaceae, which is not a large family, but includes some horticultural gems.  In California the family is represented by Fremontodendron, the Flannel Bush, whose showy display of large yellow flowers make it popular with gardeners.  Plants in the Sterculiaceae lack petals, but the sepals are colored and petal-like.

Image of B. discolor branches

The term Bottle Tree is sometimes applied to Brachychiton trees, and while the trunk of B. discolor is a little on the stout side, this trait is much more pronounced in B. rupestris.  Mature specimens of B. discolor may attain heights of over 90 feet (30 m), but even after several decades our tree has reached only about 25 feet (8 m).  The leaves drop with the arrival of cold weather in the winter, and new ones emerge in about March.  Flowering occurs in the summer.  In past years, our tree has flowered only on some branches, and these particular ones would lose their leaves, presumably so that the flowers can be readily spotted by pollinators.  However, this year it has shed all of its leaves and is flowering throughout the canopy.  The buds are covered with a golden-brown fuzzy coating, which persists on the base of the open flowers and as a stripe continuing up the middle of each sepal on the outside.  The sepals are united into a cup in their lower halves, with 5 lobes flaring outward above this.  The face of the flower is pink, as are the margins of the sepals on the outside.  Newly-opened flowers are a pale pink, which darkens by the time they are shed.  Although the flower face is not densely wooly, like the outside at the base and extending up the center of the sepals, it is still minutely hairy like the skin of a peach.

Image of B. discolor flower

The seed pods of B. discolor are very tough and somewhere between woody and leathery.  They are fuzzy like the flower buds and up to 6 inches long.  They split open along one side, and are full of coarse irritating hairs within.  Amongst these hairs are chalky yellow seeds encased in a papery coating.

Text and photos by Brian Kemble.

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The mission of the Ruth Bancroft Garden, Inc. is to preserve this exceptional example of garden design and to continue to develop its collection of water-conserving plants for the education and enjoyment of the public.
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