As part of the commemoration for the centenary of the First World War battle of Verdun on 21 February 2016, a war memorial landscape in Purley, London Borough of Croydon, named the Promenade de Verdun, was added to Historic England's Register of Parks and Gardens of Special Historic Interest. Sally Williams in The London Gardener first brought the site to our attention in 2009.

The Battle of Verdun in 1916 was the longest single battle of the First World War. The loss of life and the number wounded was huge, and almost a million soldiers were killed. It was a national struggle, a battle for the survival, the honour, and the sacred heart of France. The ordeal of Verdun is even more deeply ingrained in the French consciousness than the Somme is in the British.

The Promenade de Verdun was designed in 1922 by William Webb (1862-1930), creator of the Woodcote Estate in Purley; he conceived the idea of an Anglo-French memorial as 'a tribute to our fallen neighbours' to commemorate French sacrifices on the Western Front. Writing in the Purley Review in 1927 prompted by a visit to England by the French President, Alexandre Millerand, Webb explained the rationale behind his philanthropic gesture. While relations between England and France — which King Edward VII had fostered and the war reinforced — might become strained in the future, Webb hoped that the tribute would cement the friendship between the two nations.

For his memorial Webb chose a site on the estate where the land rises and which suggested the opportunity for an avenue leading up to a tall granite obelisk as a focal point from which views of five counties could be seen. He chose Lombardy poplars, typical of French roads, to line the avenue and he planted them in ten tons of French soil, donated by the French Minister of the Interior and transported from Flanders, where the British and French had fought side by side in late 1914. The British Consul at Lille and the Institut français du Royaume-Uni both helped to execute the entire project. It was a news item in the Croydon Advertiser in 1922 and in Country Life the following year, where it was mentioned that the memorial shows that 'we have not forgotten our comradeship in arms'.

As a memorial landscape to commemorate French sacrifices on the Western Front, it is highly unusual. Indeed, it is striking how few references there are in English memorials to the country's principal ally. Although, a number of streets are named after the battle and there are several tree memorials to Verdun. In December 1916, as a result of an appeal by the London and North-Western Railway Company, acorns collected from the French forests of Vaux and Douaumont near Verdun were sent by the Mayor of Verdun to sell on behalf of the War Seal Foundation, a charity helping disabled veterans. Several arrived at Kew Gardens, where 21 oaks and eight horse chestnuts were raised. Saplings of one horse chestnut and two oaks were planted at Kew on Peace Day in July 1919 but only one has been identified with any certainty. Unfortunately it had to be felled after it was badly damaged in a 2013 storm. However, it lives on in other ways: planks from the trunk will form a commemorative bench on the site and a piece of the tree has been kept in cold storage ready for grafting on to new rootstock. Some of the saplings raised at Kew were sent elsewhere, including two oaks reported to be planted on Petersham Common in 1920. The Western Times mentioned that a resident of Ealing presented two chestnuts and an oak tree to be planted in Walpole Park in 1917; but despite enquiries and a search through Ealing archives, no trace of these can be found. The Woodland Trust has launched a search for any remaining Verdun oaks in Britain.