DAVID WHEELER
TAXODIUMS
We know that willows and poplars are thirsty trees. In the tropics and subtropics, the guzzlers include the mangroves, invasive and colonising thugs with a preference for brackish or salty water. Thankfully, they cannot survive in our temperatures.
Here, we can successfully grow a stately tree from the Gulf of Mexico’s freshwater coastal plains and other warm, south-eastern parts of the USA; but it’s not for the small garden. Taxodium distichum, commonly known as the bald or swamp cypress, is a slow-growing giant, many examples of which – delightfully and, perhaps, surprisingly – adorn the wetter parts of numerous parks and private estates across the UK. The clue is in that second vernacular name: ‘swamp’. This deciduous conifer (tolerant, too, of less liquescent sites) is perfectly suited to the shallows, where it craftily blurs the line between dry and watery worlds.
In its homeland, the tallest known individual (climbing to 150 feet) stands near Williamsburg, Virginia. The most elderly – said to have endured more than 1,600 summers – is in Bladen County, North Carolina, distinguishing it as one of the oldest living plants in eastern North America. But oldies desirous of such a tree cannot expect to see it mature. My own taxodium, admittedly a mere eight-inch seedling when planted three years ago on the edge of a freshwater pond, is not yet waist-high.
As ever, one grows trees for the benefit of future generations.
Now here’s something about taxodiums to amuse the kiddies: the trees have ‘knees’. These spongy, anthropomorphically-named, knobbly, aerial roots (pneumatophores, to give them their proper name) are normal among hydrophytic (water-loving) trees. But those of the taxodium do indeed resemble bent, protruding knees of the human kind, making any that appear in surrounding turf a worry for those who mow the grass. They were thought to help the tree breath when grown in water. But, since taxodiums are also straightforwardly terrestrial, these outcrops are now believed to act as stabilisers.
Tree expert Hugh Johnson wonders, too, if they might function like the camel’s hump, to store nutrients. Or are they, more prosaically, he asks, like our earlobes or little toes – there because they’re there? If you’re out and about with grandchildren, the knees can be seen at Kew Gardens and along the Taxodium Walk in the Pheasantry Woodland Garden at Bushy Park, near Richmond, Surrey, and in St James’s Park near Buckingham Palace. Further afield, I’ve seen prime examples at Bodenham Arboretum, Worcestershire.
I bumped into many taxodiums in Italy this year. On an Oldie garden tour to Lakes Maggiore and Como, we saw them ‘striding’ into the depths, like Tolkien’s Ents, at Isola Bella and Bressago. Their delicate, fern-like foliage filtered the sun, shining like splintered glass on clear water around the shorelines. As if to prove the tree’s terrestrial credentials, there were many protuberances around a mature specimen on Isola Madre’s upper slopes, where roots couldn’t possibly reach the lake.
Like several other deciduous conifers – larch and ginkgo, for example – taxodiums give a good show as the year advances. From September on, says Hugh Johnson, the summer-long, yellow-green foliage turns ‘by deepening stages to a ripe ginger-brown’. At his former garden in Essex, Hugh planted a taxodium alongside a larch, whose own ‘autumnal gold, interspersed with the steel-blue of Scots pine’, provided one of the season’s most compelling compositions. Joy of joys, he reminds us that, like the closelyrelated dawn redwood ( Metasequoia glyptostroboides), taxodium cuttings taken from leading shoots strike easily. So, who’s for an arboreal knees-up?