Most gardeners in the temperate world take autumn colour for granted. As soon as September is by, their shrubs and trees flare up and transform their gardens into chromatic fireworks. This, sadly, is not always the case in Shetland gardens. There are several reasons for this, such as those non-summers, like the past one, when it’s been too cool and damp for plants to change their starch/sugar ratios in favour of the latter. A lack of sugars equates with a lack of autumn colour.
Then we have those equinoctial gales. Some years they have little or no impact, while in others, such as 2011, they blow with great ferocity and tear the leaves, still green, off the trees.
Finally there are plants who don’t manage to shut down shop early enough. Used to a different climate, they throw the switch too late and don’t start to absorb the nutrients from their leaves back into the roots – the process which causes those spectacular colours – until too late in the season.
Autumn colour at 60º North is a hit and miss affair and we must be grateful for small mercies. The gardener who selects plants solely for this purpose had better prepare for disappointment now and again, or play it safe with the following:
Enkianthus campanulatus performs regardless of weather and climate, as do witch hazels and deciduous azaleas. Aronia melanocarpa is another suitable candidate but tends to shed its leaves the minute they’ve reached chromatic saturation. It’s one of those plants that presents gardeners, especially those with small gardens, with a dilemma. Berries and autumn colour are the Aronia’s major assets. Apart from a brief flush of white flowers, it’s a dull dog, too dull to give it a prime, sheltered location, where its autumnal glory lasts a little longer.
There are two rowans in my garden I wouldn’t like to be without at this time of year due to their fiery autumn colours. Sorbus commixta is a native of Japan, the Russian far east, Korea and Sakhalin Island, and grows into a handsome small tree with domed heads of creamy-white flowers and bunches of orange red berries.
The hybrid origins of Sorbus ‘Joseph Rock’ have been lost in the mists of time but judging by the number of leaflets, has a good dose of Asiatic blood in its veins. My young specimen has yet to produce any amber berries, but makes up for this failing with a bewitching mélange of orange, copper-red and purple in October. Both are suitable for small gardens and need little or no maintenance.
The Icelandic and coastal Norwegian clones of Betula pubescens thrive in cool, wet climates and, provided those gales don’t throw a spanner in the works, turn a luminous yellow at the end of their growing season. This autumn, the gales did throw an enormous spanner, but spared some yellow closer to the ground.
Spiraea betulifolia is a twiggy, little-known Asiatic shrub, small enough for the rock garden and a perfect delight during May and June when its branches are outlined with creamy-white corymbs. Its autumnal transformation depends on location – birch-yellow in shade, copper-orange in full sun.
Berberis wilsonii is a tough, fiercly thorned shrub with clusters of small yellow flowers in early summer and turns a stunning crimson purple, especially when grown in a container.
The common beech, Fagus sylvatica, hangs on to its papery brown foliage all winter, and tends to struggle in an oceanic climate, while its southern cousin, Nothofagus antarctica is very much at home here and one of the best large trees for autumn colour – bright, buttery yellow.