22 Aug 2022

Visit of the British Pteridological Society to the National Botanic Garden of Wales

Matt Smith

We are developing a fern collection and asked the British Pteridological Society to come and give us advice.

The Broadwalk has an existing stumpery near the Gatehouse. There are also pockets of ferns located underneath 2 specimens of Fagus sylvatica f. purpurea on the Broadwalk.  One of these is located about halfway up the Broadwalk and is currently underplanted with a good selection of UK natives.  The other resides in the Japanese Garden and forms the backdrop to the bed recently planted as part of the development of the Japanese Garden.

The ferns that live in these areas seem happy, so we thought we would research the potential of developing the fern collection in these areas.

We contacted the British Pteridological Society (BPS) to see if they would like to be a part of the developments.  They came over for a visit and we had a look at the 3 possible areas and then discussed the project.

I thank the local BPS group for their generosity of time and knowledge, which has been second to none.

From the discussions, it became apparent that the existing stumpery would be the best location to start developing a UK native fernery.  This is because the microclimates of the other 2 locations would require more change to ameliorate the growing conditions to make them conducive to a more biodiverse fern flora.

We sketched out some potential design ideas, a possible acquisition list of ferns, and agreed for the local BPS group to organise further site visits, firstly to help to identify ferns within the wider estate, and to share their knowledge more generally.

And thus on the 23rd June 2022 the BPS kindly visited the Botanic Garden.

In the morning, using fronds collected the previous day, Sue Dockerill gave a wonderfully communicated and informative demonstration of the identification features of both the commoner native ferns we might expect to see in the Botanic Garden and others that might be useful in the planned native fernery.  I thank Sue for her time in these endeavours.

In the afternoon, we ventured into the landscape with the BPS members to identify ferns present on the estate.

Our route took us into the restored landscape and into the Waun Las National Nature Reserve.  We headed across Llyn Mawr, towards the cascade, to the waterfall view, Llyn Felin-gat, and then to Cae Trawscoed, returning through Fairy Woods and the Wallace Garden.

The season had seen dry conditions in the run up to the visit, however the ferns were on good form.  4 species of Dryopteris – Dryopteris affinis, Dryopteris borreri, Dryopteris dilatata, and Dryopteris filix-mas were found growing close together on the edges of the light woodland on the sides of the track.   Bracken Pteridium aquilinum and the horsetail Equisetum arvense were found in the vicinity of the Dryopteris species.

Heading across the meadows the abundance of wildflowers included the beguiling greater butterfly orchid Platanthera chlorantha.  Leaving the meadow, the path-side vegetation saw Athyrium filix-femina and Polystichum setiferum.  Heading over the bridge we noted the first epiphytes, hanging on branches hanging close to the water.  Noted by the BPS to be a Polypodium species, probably P. vulgare, but unverifiable from the ground, and due to the time of year.

We headed towards the cascade, and with the microclimates increasing in moistness the vegetation became lusher as we followed the water.  Streamside vegetation heralded Asplenium scolopendrium and then Struthiopteris spicant.  As we followed the stream there was an increasing abundance of ferns.  Polystichum setiferum and Struthiopteris spicant increasing in frequency, with the Polystichum for me, stealing the show.

There was an interesting specimen of Dryopteris that was posited to be Dryopteris affinis subsp. paleaceolobata, but would require further verification.  The waterfall section is a wonderful area of the garden and would warrant further study.  The hydrology has the potential to change quite significantly in the seasons, with the water levels being low at the time of the visit.  These features are theatrical and complex, offering interesting microclimates and ecological niches.  Habitats like this are iconic, and perhaps should have a significant bearing on the design of the UK native fernery.

We had a gander around the Victorian dipping pool on the way back to Fairy Woods and saw diminutive examples of Asplenium trichomanes subsp. quadrivalens and Asplenium ruta-muraria amongst stone hard landscaping features.  These reappeared on the walls within the Wallace Garden on our return.

A thank you to all involved with the day.  We look forward to welcoming the BPS back to the garden in the autumn for a fern propagation workshop, a lecture on some of the ferns of Wales, and to begin the sensitive collection of native ferns from the landscape to the fernery.