Dulwich Trees Profile No. 2

Our Magnificent Zelkova by John Hughes and John Welton

The Zelkova which looms so magnificently over the South Circular at the busy College Road intersection is probably Dulwich’s most splendid and awesome tree, as well as being one of its rarest. Zelkovas belong to the elm family but thankfully do not share their vulnerability to Dutch elm disease. There are six species of Zelkova worldwide, of which only three attain a large tree size, the others being large shrubs.

The Dulwich tree is the largest of all the species, a Zelkova carpinifolia. Zelkova is derived from the vernacular name used in Georgia in the Caucasus, where the tree is native (see below). Carpinifolia means “having hornbeam-like leaves”, carpinus being the Latin name for hornbeam. The tree is sometimes aptly referred to, in English, as a Caucasian Elm. There are two examples of the Japanese Zelkova, Zelkova serrata, in Dulwich Park, both rather hidden behind the shrubs in the left-hand bed shortly beyond the College Road entrance.

Our Zelkova is a tree that we all see in Dulwich but rarely have time to appreciate. The best way to do that is to go close beneath it and look up. The sheer size, beauty and form of this spectacular tree can then be seen. It has the characteristic short, thick, fluted trunk and up-swept "witch’s broom" branches of the species. In preparing for this article we gained access into the centre of the rising branches about 10 feet above the ground with the aid of a ladder. A natural "hidey- hole" has been formed , almost big enough to pitch a tent in, and when you look up you get the most glorious view of the towering branches and sky beyond. It is a magical spot, although the Estate would be unlikely to welcome the sight of sprightly readers shinning up to see for themselves.

Zelkovas were first introduced into this country in 1760 and the Dulwich tree is probably one of the earlier plantings. It is one of the best specimens in the country at over 94 feet tall, with a trunk girth measuring 16 feet at its narrowest, rising to an enormous 26 feet just before the trunk divides into its multi stemmed effect. This is bigger than the largest Zelkova at Kew and its still growing!

Other distinguishing features of the Zelkova, apart from the hornbeam-like leaves, are the smooth grey bark with orange patches and the slender green/brown shoots. The fruit is a small nutlet 5-6mm in diameter, but it is rarely produced in this country. The wood is extremely hard. Indeed, the Georgian name for the tree, from which the word Zelkova is derived, is dzel meaning “bar” and kva meaning “rock”. The tree is used there for making rock-hard and durable bars for building. Interestingly, in its native Caucasus, the tree has a much more normal pattern of growth without the “witch’s broom” effect which distinguishes it in this country. Zelkova is affected by our climate being less severe in winter than its native climate in the Caucasus. This encourages it to come into leaf earlier and it is then more vulnerable to late frosts. The frosts can kill the leading bud growth, resulting in side shoots taking over, producing a multi-stemmed effect.

The noticeable lean of the relatively short main trunk probably happened a long time ago, maybe in a storm similar to the one we had in October 1987. Judging by the size of the reactive growth, this may well have been over a century ago. Since then the tree has clearly been actively strengthening key areas, such as the buttress rooting on the side opposite to the lean, which has developed into an enormous anchor. Amazingly for the size and age of the tree, there is no dead or diseased wood visible in the crown.

The Estate continue to be proactive in terms of monitoring the condition of the tree and gaining expert advice on its safety. There was a threat to the tree some years ago but thank goodness it has been allowed to continue to amaze us all. As a precaution, however, a young Z.carpinifolia was planted a few years ago on the little green across the path from the present tree.

So, next time you are stuck in traffic on the South Circular or, as a pedestrian, are waiting an age for the Pelican lights to change, look up and enjoy this remarkable tree, one of the most picturesque and distinct of any that can be grown in this country and undoubtedly one of the true glories of Dulwich.

This is the second in a series of articles by members of the Society’s Trees Committee. The committee’s tree map - Remarkable Trees in Dulwich - is available from The Art Stationers, Dulwich Village ( price £3.50).