Leaves are turning late this year thanks to an incredibly mild autumn. Warm dry weather isn’t ideal for vibrant leaf colour, but a few stalwarts are at last coming good.
Leaves change colour in autumn because fewer daylight hours mean less time for them to make enough chlorophyll to remain green.
As their green colour fades, the underlying reds and yellow that are always there, in greater or less amounts depending on the plant, start to show through.
Strictly speaking weather doesn’t affect autumn leaf colour. But you and I know that in a dry year, plants simply shed their leaves as a defence mechanism against lack of moisture before turning.
Too much rain, not normally an issue for any of us, also means less sunlight and correspondingly less colour.
Sunny days, cool nights and enough ground moisture for plants to hang on to their foliage for a few weeks are ideal. I’ve been anxiously watching a new ornamental pear I planted last winter, Pyrus fauriei ‘Korean Sun’, to see how it colours. I’m thrilled to report that it’s absolutely gorgeous, shiny scarlet and orange and lasting well despite dry conditions. Flemings Nursery say ‘Korean Sun’ shows good drought tolerance though a damp well-drained soil produces best results. I wish, but I’m still pretty happy with mine, and it’s certainly better than my Manchurian pear (P. ussuriensis) which took one look at April’s weather forecast and dropped its leaves overnight. If I had deep, reliably damp, well-drained soil I would hasten to plant a tupelo (Nyssa sylvatica) as it also has shiny leaves and spectacular autumn colour.
I’ve been anxiously watching a new ornamental pear I planted last winter, Pyrus fauriei ‘Korean Sun’, to see how it colours. I’m thrilled to report that it’s absolutely gorgeous, shiny scarlet and orange and lasting well despite dry conditions.
Bill’s mother lived in high rainfall New England where tupelos grow beautifully and was always on at me to plant one. But they come from swampy regions of eastern North America so I never trusted it to grow in my garden with its weeks of summer drought.
A tree is a big investment in your garden’s future and it pays to research its place of origin. It’s heartbreaking to bring a tree through its youth only to lose it when it gets too big to water by hand. One of my best trees is the medium size, obligingly drought tolerant Chinese pistacia (P. sinensis) with large, pinnate leaves whose sensational autumn colour never fails. The Chinese dawn redwood (Metasequoia), a deciduous conifer, turns a rich russet brown in autumn. Discovered during World War II, it now grows all over the world, its narrow, conical shape a familiar sight in gardens in Shanghai and the Yangtze River valley.
Don’t forget climbers when thinking about autumn colour. Virginia creeper (Parthenocissus tricuspidata) turns slowly from yellow to orange and red and soon races up a bare wall.
Southern Highland Botanic Gardens hosts ‘Music in the Gardens’, featuring singers and musicians, on Sunday May 29, 11am-1pm, entry free, take your own chair. Tea, coffee and cake from Snax on Trax, plant stall. Phone 02 4861 4899 or visit www.shbg.com.au/music-in-the-gardens/
