Alder Collection
In 1991 we planted 18 species of alder along the valley floor at Seven Oaks in St Brelade, forming a collection unique within the British Isles. The project was partly a response to the devastating impact of Dutch elm disease in the 1980s, with the further aim of identifying species best suited to our climate and soil.
Most of the alders have now matured into fine specimens and in 2023 the project gained accreditation from Plant Heritage as a National Plant Collection.
As of 2026 there are 36 living alders in the arboretum, with 13 species represented. Examples include three endangered seaside alders (Alnus maritima), five oriental alders (A. orientalis), which can grow 50 metres high, and four of Britain’s only native, the black or common alder (A. glutinosa).
You can see a photo of each individual tree, as well as its details and location, by using the interactive map that’s accessible through the link on the right.
Our thanks go to the Alder Collection’s sponsors, CoinShares, for the funding that keeps it beautiful.
Visit the Alder Collection
From St Aubin, head up Mont Les Vaux and turn right at the big bend into Le Mont des Longchamps.
From Red Houses, drive down Rue des Genets and continue until turning left into Le Mont des Longchamps, on the bend just after the shell house.
Entering Le Mont des Longchamps, you’ll see Mont Nicolle ahead to the left. The Alder Collection is in the valley on the left as you enter Mont Nicolle, marked by a National Plant Collection sign.
Limited on-road parking is available on Le Mont des Longchamps.
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What we've achieved together
Since our foundation as Men of the Trees in 1937, we’ve evolved to become an important part of the community, planting and protecting thousands of trees while helping people to understand and appreciate their importance to our existence.