Dyffryn Gardens Arboretum

On Thursday 14 Sept, Cardiff Naturalists took a tour of the arboretum at Dyffryn Gardens with the new arboriculturist Rory Ambrose. Rory started work at National Trust Dyffryn Gardens in November 2016, bringing with him many years’ experience of working at Kew Gardens.

He told us of the National Trust’s five-year plan to restore the arboretum to its former glory as a “woodland garden”, with the clearance of overgrowth to let important trees flourish, a greater emphasis on parkland tree species, and better integration with the rest of the Edwardian gardens.

Systematic tree planting started at Dyffryn back in the mid-eighteenth century. Among the oldest ornamentals are the Lucombe oak on the Archery lawn, thought to be over 400 years’ old. Reginald Cory and Thomas Mawson developed and extended the gardens at Dyffryn between 1906 and 1930, including the tree collection in the form it is seen today. Unfortunately, there was a period of relative neglect for several decades, up to 1997 when Vale of Glamorgan Council purchased Dyffryn Gardens. The National Trust acquired the house and gardens in January 2013.

We started our walk by the visitor centre, stopping first at Kennel Bank to the left of the path to Dyffryn House. The heather beds established in the 1970s have now gone. This area is being prepared as a wild flower meadow, with some new areas of heather being replanted. Around 80,000 bulbs are to be planted on the bank, including 6,000 crocus bulbs of several varieties. The long-term aim is for a pastoral woodland landscape, which will include native orchids.

The 22-acre arboretum at Dyffryn is divided into 37 areas for the purposes of management. Rory explained that the plan was to concentrate on restoring 5 to 6 areas, such as the Kennel Bank, each year, “to do small areas really well rather than spreading ourselves too thinly”.

Walking up the path into the arboretum from here, we pass the first of many Champion Trees: an elm. The focus is on UK Champions: those trees that by virtue of their girth, height or distinctive characteristics are considered to be the best examples of their kind. One aim, in the next few years, is to establish a new Champion Tree trail, to guide visitors to these outstanding specimens.

Noting some of the characterful and quirky tree shapes, Rory noted the role of Victorian nurseries, where seedlings could become pot-bound before planting. “Today’s nurseries are too good,” jokes Rory, as they result in more uniform trees!

Unfortunately, some of the Champion Trees have suffered through insufficient woodland management. At least three UK Champions in the Crataegus (hawthorn) collection, for instance, have died amidst the overgrowth; the clearing of which is a major management challenge for Rory and his team.

Among the other UK Champion Trees pointed out by Rory were a magnificent hornbeam (Carpinus betulus ‘Fastigiata’), and Dyffryn’s famous Acer griseum, grown from a seed bought back from Asia by the plant collector Ernest Henry ‘Chinese’ Wilson. This tree is now approaching the end of its life, and a barrier prevents people walking on its root plate. However, the main aim is to propagate a new tree from its seeds and plant it nearby, not an easy task as the germination rate is relatively low.

Rory showed us where he and his team are creating a natural play area from the timber of fallen mature trees. Nearby, and off limits to the public, a large concrete pad had recently been laid in the composting area. The plan is for Dyffryn Gardens to be 100% self-sufficient for green waste (compost and mulch) in the near future.

The tall yews that formed the boundary between the arboretum and the formal gardens have gone, opening up views and enabling the team to integrate the woodland area better with the gardens as a whole. Other plans for Dyffryn Gardens include the creation of a heritage orchard.

We looked at a particularly fine Metasequoia, near a delightful gourd tunnel in the walled gardens, before finishing at the Rock Garden – another area where there are plans for creating much more botanical interest within the next five years.

Back at the entrance, we thanked Rory for a highly informative and entertaining tour of the arboretum. I am sure we will all be returning to see how the National Trust’s ambitious plans transform this area back toward the vision of Dyffryn Garden’s original founders.