When it comes to the horticultural industry, the main news item at the beginning of this month has been the grant of a Royal Chartership to the Institute of Horticulture. On my way to the celebratory event held at Hatfield House (Herts), I stopped to visit the National Collections of Taxodium and Carpinus held at West Lodge Park (North West London).
This large estate has been owned by the Beales family since 1945, with the main building being used as a hotel. An arboretum was established in 1963, and it is now home to over 800 tree species from all around the world:
Taxodium is a genus of semi-evergreen conifers, named after yew (Taxus) because of their foliage similarity. Native to river and pond margins of North America, they are perfectly adapted to wet grounds. Taxodium also have gorgeous rusty red autumn colours (but I was sadly a bit too early to see them!). The National Collection holds 17 taxa, including many rare cultivars such as T. distichum ‘Peve Yellow’ or T. distichum ‘Little Leaf’. Here’s an overview of the diversity in the genus:
Taxodiums produce “knees”, which are strange cone-shaped structures that grow vertically from the roots. They were originally thought to help oxygenate the tree roots when growing in boggy soils (a bit like “pneumatophores” in mangrove trees), but knees appear to have mostly an anchoring function (to prevent the tree from falling in unstable soils). One thing’s for sure: they can pierce through a car park tarmac surface…
The other National Collection held at West Lodge Park is Carpinus betulus cultivars, with 11 different taxa. Hornbeams can be used for their very hard timber, but they are also beautiful garden trees. Here’s Carpinus betulus ‘Pendula’ on the left and C. betulus ‘Fastigiata’ on the right:
C. betulus ‘Quercifolia’ is another pretty cultivar with oak-shaped leaves. Sadly, some branches seem to revert to the species standard leaf shape…
The Beale Arboretum is also home to great collections of Magnolia, Catalpa, Ilex, maples and rare conifers. It can be visited every day, from 2 to 5 pm.