A Gardening Journal
Fabulous in the Fall: Coral Sun Koelreuteria
- Published: December 14 2016
Even the straight species of Koelreuteria paniculata is unique: it's the only hardy summer-flowering tree whose blossoms are butter yellow, not white. Above-left is its Coral Sun cultivar, which does everything but flower. Given the spectacular show the flowers of the species make, it's incredible indeed to suggest that with Coral Sun, you won't miss them.
Coral Sun provides eye-popping and complex displays each season of the year, involving separate shows of the leaf blades and their petioles, as well as the bark of its young stems. Compared to such dextrous versatility, mere flowers would be so obvious. Here, then, the first of many looks at this remarkable tree at the height of its display of fall foliage: As summer heat turned chilly, the pinnate leaves and their petioles both turned pale yellow.
Coral Sun is nothing if not clever in each of its parts. Far from being supporting structures to the leaflets—mere background in the yearly cycle of this tree's multi-act show—the petioles have their own performance arc: they had been bright raspberry all spring and summer, during which time the leaflets were first coral-pink, then pale green.
The picture below shows just one of the range of partner plants the seasonally-shifting displays of Coral Sun make possible. The plant at the right, with small green foliage and spikes of yellow-and-raspberry flowers, is a containered ever-blooming subtropical shrub, thryalis. It leaves the greenhouse in spring to enjoy the warm months sunk into the garden bed before returning to frost-free shelter in the fall.
All summer long, the raspberry petioles of the Coral Sun foliage called out to the bright raspberry centers of the thryalis flowers and the softer raspberry of the shrub's young stems. For the weeks of fall before hard frost would damage the shrub, that link shifted to the yellow shared by the thryalis's petals and the tree's now entirely-yellow leaves and petioles. Although the display of the thryalis hadn't changed, its context had: the notes of raspberry were now the contrast to Coral Sun, not the link with it.
In 2017, I'll revisit Koelreuteria paniculata 'Coral Sun' in spring, summer, fall, and winter. I'll also provide the full how-to-grow-it table.