The ingredients for flaming leaves

The ingredients for flaming leaves | In Fiona's Garden

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European smokebush (Cotinus coggygria flame) has large, dark green leaves and brilliant, long lasting autumn colour.

European smokebush (Cotinus coggygria flame) has large, dark green leaves and brilliant, long lasting autumn colour.

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You need the right combination of rain, sunlight and low temperatures to produce decent autumn leaf.

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A damp evening in early winter is a lovely time in the garden. Autumn leaf colour varies from year to year and a storm can sweep it away overnight, but this year we've been lucky, with showers but no wind.

I first consciously noticed the beauty of autumn leaves long before becoming a gardener. I was working my way round the world - which luckily I could do in those carefree pre-covid days - and was weekending with friends in the Laurentian Mountains north of Montreal.

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On the way we stopped at a roadside café where a tiny back window framed the flaming scarlets, russets and golds of the maples covering the surrounding hills. I'd never seen anything like it and the image remains imprinted on my mind's eye to this day.

You need the right combination of rain, sunlight and low temperatures to produce decent autumn leaf colour.

Highland and inland gardeners in NSW have sun and low temperatures but our autumns are often dry and foliage either falls quickly or fails to colour altogether.

The yellow and orange pigments that produce autumn colour in deciduous trees and shrubs are present in the leaves from when they sprout in spring.

But they're hidden by the green chlorophyll which absorbs energy from the sun and turns carbon dioxide and water into the carbohydrates needed for growth.

As daylight hours shorten and temperatures drop in autumn the leaves stop making food, the chlorophyll breaks down and the green vanishes, leaving only the yellow and orange pigments.

In some trees, red pigments may develop and the chemical change produces additional colours like the crimsons, wine reds and purples found in maples, dogwoods, Australian Claret Ash (Fraxinus 'Raywood') - and lots of others.

Pears and crab apples are usually first into colour here and are now finished.

Trident maples (Acer buergeranum) were disappointing - I don't know what it takes for this picky tree to turn heavenly bright scarlet, it happens so rarely - but crepe myrtles (Lagerstroemia), medlars (Mespilus) and Prunus 'Elvins' have stayed orange, gold and bronze for weeks.

Chinese quinces (Cydonia sinensis) are turning vermilion and gold now, for once perfectly timed to coincide with the yellow fruit. This is a rare pleasure, all too often the leaves drop well before the quinces get their act together.

Several shrubs are looking good, among them Physocarpus 'Diablo' whose leaves hang on for weeks, unlike the best may bush for autumn colour, Spirea prunifolia. Its shiny, oval leaves turn deep red and orange, but alas fall afterwards, though are glorious while they last.

The last hurrah of autumn comes from European smoke bushes (Cotinus coggygria). 'Grace' is first, brilliant, glossy scarlet, followed by 'Flame'. The show ends with "Royal Purple' whose purple leaves are shot with red and orange.

Smoke bushes are happy in dry soil, one of the reasons I grow them.

Autumn flowering, white nerines (Nerine flexuosa alba), as it happens, like dry shade, so are perfect companions, thriving on neglect while slowly increasing, no gardener could ask for more.

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