Against expectations, in Britain we have been having a beautiful fall. I know it cannot compete with Vermont, but after nine weeks of summer drought it has been a delight. Until the third week in October the days were mostly sunny and viewing was a pleasure. Rain then interposed, but not before autumn colours as good as I remember.
October 13 used to be wise gardeners’ cut-off point. Frost was imminent and anything half hardy in a pot needed to come indoors. Dahlias were doomed. Pelargoniums were on borrowed time. Cosmos daisies had already blackened at the first degree of midnight chill. This year, we have had one cold night but not enough to interrupt the late late show that is modern British gardening. The pattern of warm autumns gives us another four weeks of flowery pleasure.
Some of the best early colour has been seen, poignantly, on ash trees. In East Anglia, the south-east and the south-west, these trees have been ravaged by the fungal disease ash dieback, leaving them as dead skeletons. Not all ash trees, however, are affected and in the heat of this summer the disease has been noticed by some to have made less progress, an observation which needs to be scientifically tested and diagnosed. Surviving ash trees have often coloured beautifully in the clear cool days of early October. Nobody will plant them now but the sight of an ash’s yellow autumn display is a memory to take forward into the gloom.
Sorbus trees are another matter. Most of those from east Asia have struggled in Britain in the long drought and even one of my most dependable colourers, Sorbus commixta from Japan, has been so ravaged by dry weather that its showing this October is muted. European sorbus trees have been more resilient. As a tree in boundary hedging or farmland, our rowan, Sorbus aucuparia, is always good value, but I am more excited by two yellow-berried newish-comers.
Sorbus aucuparia Streetwise is definitely one to track down. It has big clusters of yellow berries, not red, from early autumn onwards and its pinnate leaves then turn an excellent orange, as this year has been confirming. The extra plus to it is that it is not a wide-spreading tree and can be fitted responsibly into medium-sized gardens. Allow for a height of about 20ft and a spread of about 10ft after 20 years. Sorbus trees can also be shaped as they age by taking off their lower branches in early spring.
Sorbus aucuparia Sunshine is just as good. Its eventual spread is wider, up to 12ft, but it too stops at about 20ft in height and has masses of excellent yellow berries in early autumn. It is worth having it as well as Streetwise if you have room as its autumn colour is different: its pinnate dark green leaves turn to red-purple whereas Streetwise colours to orange.
These fine trees are variations on the mountain ash but they are not at risk of ash dieback. Botanists put them in the rose family, far removed from true ash trees. The enemy of the sorbus is fireblight but Sunshine and Streetwise have been selected for strong resistance to it. They are fine, robust choices.
As usual I am revelling in the fine show of berries and autumn colour on several crab apples, especially Malus Evereste, one for anyone with a modestly sized garden. Remember that crab apples too can be thinned by pruning to keep them to a manageable density and size: they are first-class trees for a succession of beauty throughout the year, flowers, then fruits and autumn colour. Evereste’s leaves stay fresh and green all summer, even in one like 2022.
We are all rather reticent about the colours of low-growing perennial plants. You will not have much joy, except autumn flowers, from the lovely Japanese anemone or from most of the Michaelmas daisies: I cut them down as soon as flowering is over.
Other families need to be noticed, the blue-flowered amsonias and the fashionable sanguisorbas being two to explore. Amsonias are excellent blankets against weeds and have flowers of pale or slate blue, tabernaemontana being the most vigorous. It is turning a fine yellow just now, giving a second season after its flowers in early summer.
Sanguisorbas are burnets in the wild, elegant plants with heads of flowerlike bottlebrushes, much admired by modern wilders and prairie planters. Many of them have fine autumn colour, the very opposite of those other wilding staples, the rudbeckias, which turn to a miserable black and need immediate cutting down. Sanguisorbas were little grown or known 30 years ago, but the changing taste for supposedly wilder gardening has propelled them to the fore. They are also easy to raise from seed.
At ground level, we need to keep our eyes open and appreciate autumn colours in borders as well as on tall trees. In between come many of the acers, the lovely maples that are small trees or shrubs. In late August I was pleased to see how relatively little damage the dry weather was doing to the many fine acers built up in Lord Heseltine’s ever-growing wonder, the gardens round his home at Thenford, Northamptonshire.
Last week, in another nearby arboretum I enjoyed yet more acers in fine colour, this time in the 60-acre woodland of Evenley Wood Garden, now regularly open to the public.
From 1980 onwards, the wood was steadily planted by a long-serving RHS committee member, Timothy Whiteley, who had noted its unlikely assets, green sand and a band of acid soil in otherwise alkaline country. On his death in 2017, the wood passed to his daughter Nicola, ignorant about trees and gardens but expert in horses and riding. She took up the challenge, and trees have taken her off the saddle: the wood is now attracting 30,000 visitors a year, covering the costs of its maintenance and improvement (evenleywoodgarden.co.uk).
Under a heavenly blue sky there, I had my best acer moments this year. Many of you garden on acid soil and are ideally placed to plant acers for autumn. Here are three of the best I noted, glowing under the autumn sky as small trees, not shrubs.
Acer palmatum Senkaki turns a sensational yellow. Acer palmatum Trompenburg is a tree with three seasons, beginning spring with leaves of dark purple, turning to green and then in autumn to orange-red: it grows steadily to about 12ft high and 9ft wide and is excellent for smaller gardens, as its RHS Award of Garden Merit testifies.
Acer palmatum Bloodgood is, well, bloody good too. It turns to a superb crimson red in autumn so long as it is not in too dry a soil or out all year in blazing sun. It spreads into an even wider shrub than Trompenburg over time, so it cannot be used as a vertical accent. The housing squeeze will keep us all rooted where we are: sit still and plant a Bloodgood for the long term.
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