Of the many forms of elm once to be encountered in rural England – most of them now rendered all the more anonymous by the loss of all mature specimens – the Plot elm is perhaps the most intriguing. The questions which arise in connection with it are these: what is it; where did it come from, and how did it achieve its current distribution?
It only ever occurred in abundance within the small triangle formed by Newark upon Trent, Grantham and Lincoln, and at a completely separate location, around the village of Laxton in Northamptonshire. Elsewhere in the East Midlands it had a scattered distribution, though isolated trees were identified as far afield as the Welsh Marches. There is a surviving mature tree, clearly an amenity planting, in Edinburgh. Elms of the Plot type are not found in continental Europe.
The main peculiarities of Plot, apart from its distribution, are its form, and its leaf. The growth is erect, but the leading shoot tends to lean to one side. Sometimes the entire stem is at a slight angle away from the vertical. Some branches grow upwards at a fairly narrow angle to the trunk, while others dip below horizontal. Many arch laxly down at their tips. Twigs tend to hang curtain-like from the main limbs. The shape of young trees is roughly conical, somewhat reminiscent of Gingko and quite markedly similar to Nothofagus obliqua. It may be singularly graceful, or merely amorphous. In fully developed trees a narrow, light crown eventually develops. It is often “cocked” or lop-sided (technically referred to as “unilateral”), and characterised by twisting, rather chaotic branches which rapidly peter out into a few terminal twigs. Mature Plot, at its best, is a strongly vertical, sculptural tree, something like a skeletal English elm.
The Plot leaf is understated in all respects, being mid green, rather small, with fewer, blunter serrations and fewer veins than in other elms. The smallest leaves at the base of the spray are wedge-shaped. The short shoots of Plot tend to produce eight leaves; those of most other elms produce only five.
Plot has no significant resistance to elm disease, and mature specimens are no longer found within its former range. Even within its heartlands it is thought by some to be outnumbered by hybrids with wych elm and field elm The number of people who have knowingly seen a fully grown specimen of this most elusive of elms must now be small indeed.
I have reproduced here all the photographs of mature Plot elm which I know. Four come from Gerald Wilkinson’s “Epitaph for the Elm” (there is a fifth, but of elms thought to by hybrid Plot at Mepal, Cambridgeshire). Richens’ “Elm” includes a very valuable and striking photographic study of semi-mature Plot at Laxton by Mary Neil. An old photograph of a mature Plot elm at Westonbirt can be found on the Wikipedia page for the tree.
The two main treatments of Plot in the extant literature are by R.H.Richens in the book mentioned above, and an article by Max Coleman, Michelle Hollingsworth and Peter Hollingsworth: “Application of RAPDs to the critical taxonomy of the English endemic elm Ulmus plotii Druce”, Botanical Journal of the Linnean Society (2000), 133: 241-262.
Coleman’s work seems to have answered the question of what the Plot elm is. He obtained leaves from the clone bank established by Melville at RBG Kew at Wakefield Place, including 14 selections which corresponded in all ways to “true” Plot. These and samples from other endemic elms were then studied by means of RAPDs (randomly applied polymorphic DNA). All 14 selections of Plot were found to have an identical RAPD profile, enabling the study to propose in the case of Plot that “a single clone (genotype B) has been propagated and distributed around the English midlands”. Coleman therefore had a powerful reason for rejecting earlier views that Plot should be regarded as an elm species in its own right. It is a cultivar which would have appeared to have arisen as a sport from U. minor. Its scattered distribution can be accounted for only by human agency. Plot comes out of this looking rather less mysterious and frankly less intriguing at least with regard to its natural history than some earlier botanists had imagined, and this informs one of Coleman’s conclusions:
“In terms of biodiversity conservation, a cultivated clone that falls within the range of a widespread and common species would seem less important than a rare taxon that exhibits genetic variability and is not reliant upon man for dispersal. As our data suggest that U. plotii is an example of the former situation we feel it would be inappropriate to regard it as a conservation priority”.
I would only add that this latest put-down becomes Plot very much more than would a sudden dazzle of celebrity.
Richens introduces the tree as U. minor var. lockii, and refers to it as Lock’s elm for nomenclatural scruples of his own. In the course of his survey of elms in the counties of England his main concern is to account for its oddly scattered occurrence, and he returns to the subject several times. The most significant mention is quoted below:
“A note of uncertainty attaches to Lock’s Elm. It lacks any documentation before the present [ie. twentieth] century. Its pattern of distribution is strange. It is present in quantity in a few villages along the upper course of the River Witham (Li). Elsewhere its distribution is very scattered over the whole of the north Midlands. Very rarely it occurs outside these limits as in Humberside and Cambridgeshire. When it does occur, it is often as a single tree, or perhaps a single hedgerow or around a single field. Many of the locations are alongside a road or in a hedge running into a road.
Lock’s Elm is not known on the Continent and one is driven to conclude that it must have arisen as a sport from a local Narrow-leaved Elm [ie. U. minor]. This could have occurred almost any time between prehistoric times and the beginning of the eighteenth century.
Age-and-area considerations suggest that, outside the Witham valley, this elm is of relatively late appearance. Otherwise it would have been expected to spread further and more evenly. How it has spread is not known. One line of enquiry, however, seems worth pursuing. Scattered elm trees of types not known elsewhere in the locality occur in Wales, sometimes along cattle drovers’ routes. It is also stated that farmers planted pines to indicate overnight pasture. It seems worth investigating whether the distribution of Lock’s Elm is significantly associated with drovers’ routes. If so, its odd distribution could be accounted for. Drovers’ routes have not been mapped comprehensively since they are largely known from such few drovers’ account books as have chanced to survive. The north Midlands is not well covered” (p. 54).
So, the mystery of Plot elm appears to be solved in part; it is a single clone which probably originated in Lincolnshire and was undoubtedly spread by man, possibly along droving roads. However, this begs a series of questions. Is there really evidence for that means of dispersal? It is beyond the scope of this note to tackle that. Is it at least reasonable to suppose that drovers may have spread the Plot elm? For whatever reason would they have done that?
The mapping of drovers’ roads, at least in the lowlands, is all but impossible. One of the few identifying features is the “long acre” – unusually wide verges which could accommodate the herd or flock and function as pasture along the route. However, if the drove has been turned into a dual carriageway, all traces of its former function will obviously have been obliterated. There is still something to be got from considering not so much routes as destinations. Plot’s central area of occurrence lies on the way from the pasture lands in Lincolnshire to Nottingham, where there was a major livestock market. Melville obtained his specimens of Plot from Banbury, which happens to have been the biggest livestock market in Western Europe. Only the concentration of Plot at Laxton seems rather off the beaten track as far as droving is concerned.
The notion of drovers carrying a planting stock of trees with them seems far-fetched, since apart from anything else they would surely have travelled light. However, had they wanted for some reason to plant trees, elm would have been the obvious choice since its suckers are so easy to transplant. Elm suckers can be dug up with a bit of root attached at any time during the dormant season, require nothing more than some damp rag around the base to keep them fresh for days, and do not require skilful planting or much by way of aftercare. No sideline in running a tree nursery would have been needed. That is why there are so many elms in the hedgerows; if a landowner imposed on tenants a requirement to plant timber trees, elms were cheapest and easiest.
But why would drovers do it? Their priority was presumably not afforestation nor landscape design, but to get animals as quickly and efficiently to market in a condition which would fetch the highest price. They needed to know where they were going, to be able to feed and water their stock on the way, keep them healthy, avoid their straying or theft, and so far as possible avoid paying tolls. Could Plot elm conceivably help with any of this?
Elm is extremely palatable to grazing animals, and cattle in particular. If elm in leaf is felled into a field of cows, they will stampede towards it. Could a supply of elm have provided fodder on the way to market? It seems unlikely that a few scattered trees would have been a sufficient or a practical source of fodder in quantity. Realistically what was needed was permitted overnight pasture, facilities for watering the animals and the means to stop them straying. The climbing of elms to lop off branches does not fit into the picture. Even if it did, why plant the elm which had the sparsest foliage of all the varieties available?
Perhaps in this, however, is a clue. If drovers planted Plot elm, maybe it was not because of what Plot elm was, but because of what it was not. It was distinctive – clearly not the usual sort of elm, nor likely to be taken for any other sort of naturally occurring tree. Furthermore, it was distinctive even at a considerable distance.
It could have been of use in some form of drovers’ way-marking. Richens has helpfully pointed out that pine seemed to be used in this way in connection with the provision of overnight grazing for the droving trade (this is taken from H.R.Rankin, “Cattle-droving from Wales to England”, Agriculture (1955), 62, 218-21). Granted, in parts of Wales pine could have had the practical advantage of being one of the few trees that would grow and provide all year round shelter, but first and foremost its purpose was probably by its distinctiveness to convey a message to men without maps or literacy. It seems quite conceivable that not only those who put the drovers up, but the drovers themselves, made use of signs.
Among the most important considerations for a drover must have been to find the way. That could largely be guaranteed by experience, but some of the routes in the relevant part of England were several dozens of miles long (those from Wales and Scotland far longer still). Not every man could have known every mile of the way reliably, nor be certain that he would always be employed on familiar routes. If a wrong turning were taken, it might be some time before the mistake became apparent; meanwhile the drover would find himself and the animals entrusted to him on unfamiliar and therefore dangerous territory. It would have been entirely reasonable to take steps to guard against such risks. Were a large signpost wanted, durable, unmistakeable from a distance and of necessity placed on someone else’s land, the only practical way to provide it would have been to plant a distinctive tree. Richens observed that the tree tended to occur singly and on or near roads. Plot could have been in use as a signal, perhaps giving guidance at significant points on the way.
It is unlikely that this or any other hypothesis will ever be proven. However, if U. plotii has lost a little of its fascination as a result of Coleman’s research, it gains by the possibility of unique association with an aspect of rural history.