Another use for the bottom of the Aga
Charles Quest-ritson is charmed by the horse chestnut
THE horse chestnut is the finest flowering tree hardy in Britain. I love it to the depth and breadth and height my soul can reach—let me count the ways. I love its big, dark, glistening, sticky buds, the delicate pale-green opening leaves, their palmate shape. I love the way its branches sweep right down to ground level, perfect for children’s dens. I love its habit of bearing its flowers over 5–6 weeks, starting with the lower branches on the sunny side and ending high up on the cooler northern side.
I love the flowers themselves, foot-long cones of white and pink with long stigmas and curving, upturned stamens. I love the buzz of bees working their way up a spike and pollinating as they move from flower to flower. And the way the dark conkers glisten as their casing splits open.
There are Aesculus species all over Asia and North America, but none of them quite comes up to the beauty of our well-known European native. Actually, no one knew that it came originally from the mountainous borderlands of Greece and Albania until long after it was introduced to Western Europe from Constantinople, via Vienna, at the beginning of the 16th century. Now, horse chestnuts are classic trees of English parkland: there is a stupendous avenue of them planted by the 1st Lord Fairhaven at Anglesey Abbey in Cambridgeshire, half a mile long.
The common name of the horse chestnut is, rather unusually, commemorated in its Latin epi- thet, Aesculus hippocastanum. Had it been named by an alternative botanist, such as Edward Lear, we might be calling it Aesculus conkeri. When I was at prep school, some boys said that the best way to harden a conker was to pickle it in vinegar, but I knew that the bottom oven of the Aga was much more effective.
Horse chestnuts do, however, suffer from the predations of a micro-moth known as Cameraria ohridella. This is a leaf miner, apparently indigenous to the Balkans, that spread very quickly throughout Europe in the early 2000s. I remember noticing it for the first time in 2005 at the Parc de Sceaux, south of Paris, one of whose many glories is its outer network of long avenues all planted with horse chestnuts. It was July and I could not understand why the trees all seemed to be showing signs of autumn colour.
The moth’s larvae suck the sap within the leaves and create a lattice of brown patches from early June onwards—and they’re capable of producing up to five generations in one growing season. I’ve also seen them on sycamores and Norway maples. The search is on for a biological control—parasitic wasps, for example—but none has yet been found and it’s likely the moths will disfigure trees for many years to come.
I’m not so keen on the red horse-chestnut, Aesculus x carnea, which I associate with wet picnics on school prize-giving days. It has darker leaves, which have a dulling effect on the deeppink flowers and it tends to produce ugly growths on its trunk. Botanists like it because it’s a rare example of a hybrid (between A. hippocastanum and the American A. pavia) that comes true from seed, but it, too, is disfigured by leaf-mining moths.
However, a number of species are immune to the little burrowers. In my last garden, I found that A. turbinata, the vigorous Japanese species with the largest leaves of all, was only lightly infected and A. californica was completely immune. The latter has a strange habit of opening its first flower right at the top of the panicle and this develops into a little green conker-to-be before the other flowers open. It should grow well on our south-facing chalk hillside.
I would also add A. parviflora, which is shrubby and flowers in August, but is a great spreader; a clump at Prince Pückler-muskau’s park at Muskau in Germany is some 100ft in diameter.
Best of all, and completely immune to the moths, is the majestic Indian horse-chestnut A. indica, with elegant leaflets and long, slender flowers that don’t open until June or July. It will increasingly take the place of A. hippocastanum in Britain. I’ve planted it in our new garden confident that, if I don’t live to see it flower, generations to come will will bless my memory.
‘I love the way the dark conkers glisten as their casings split open
Charles Quest-ritson is author of the RHS Encyclopedia of Roses
A pink-and-white delight: horse-chestnut flowers in April