Brecon Beacons, Powys

Although famous for their distinctive sandstone mountains, the botanical wonders of the Brecon Beacons tend to grow along their southern edge, where a band of limestone rocks supports a rich diversity of plants. Some of these are found nowhere else in the world.

Over 500 different plant species have been recorded here. The vast majority inhabit limestone cliffs, screes and pavements, where the thin, lime-rich soils support many specialist plants known as ‘chasmophytes’ (plants that grow in the crevices of rocks). These include some arctic-alpine species that reach the southern edge of their range, such as Purple Saxifrage (Saxifraga oppositifolia ) and Roseroot (Sedum rosea). But the real stars are the various unique endemic species, including Ley’s Whitebeam (Sorbus leyana) and Llangattock Hawkweed (Hieracium asteridiophyllum). The global significance of these species means the cliffs are identified as an Important Plant Area.

However, these special plants are now being threatened by the spread of non-native invasive species, primarily cotoneasters (Cotoneaster sp.), but also Rhododendron (R. x superponticum) and Cherry Laurel (Prunus laurocerasus). Without action now, populations of key plants are facing local extinction.

Our goals:

- Undertake the first detailed survey and mapping of non-native invasive plants across the cliffs.

- Identify priority areas for action and draw up management guidance for these sites.

- Identify opportunities and sites where volunteers and landowners can become involved.

- Develop a funded programme of eradication that involves landowners, local communities, volunteers and gardeners.

Under threat:

Ley’s Whitebeam (Sorbus leyana)

Growing as a shrub or small tree, this endemic Whitebeam is found only in Wales. It is thought to have originated as a hybrid between Rowan (S. aucuparia) and either Grey Whitebeam (S. porrigentiformis) or Rock Whitebeam (S. rupicola). It’s one of Britain’s rarest species, with just 16 wild plants known to be growing in two spots in the Brecon Beacons. Photo (c) Natasha de Vere.

Rigid Buckler-fern (Dryopteris submontana)

This neat little fern forms clumps of upright fronds nestled between the rocks. Although it grows in exposed areas of limestone rock, it needs shelter from the wind and hunkers down in gaps and cracks for protection. It Britain, it reaches the southern edge of its range in the Brecon Beacons. Photo (c) Kevin Walker.

Craig y Cilau Hawkweed (Hieracium cillense)

Like many of the other hawkweeds found on these cliffs, Craig y Cilau Hawkweed is a very rare endemic found nowhere else in the world. The species tend to be very similar in appearance and even experts struggle to tell them apart. Less than 500 plants of this particular species are known, all located on cliffs in and around Craig y Cilau National Nature Reserve. Photo (c) Trevor Dines.

How's it going?


Funding is secured from Brecon Beacons Trust to undertake detailed survey and mapping of 22 cliff sites for invasive non-native plants.

The survey focuses on four of the most problematic species: Entire-leaved Cotoneaster (Cotoneaster integrifolius), Wall Cotoneaster (Cotoneaster horizontalis), Rhododendron (Rhododendron x superponticum) and Cherry Laurel (Prunus laurocerasus).

Invasive non-native species are found at 5 of the 22 sites, with the greatest infestation of Cotoneaster species being at Darren Fach. Here, the infestation coincided with the occurrence of important plants including, Ley’s Whitebeam, Rigid Buckler Fern and Chalice Hawkweed (Hieracium cyathis).

Management guidelines for each are devised based on the findings of the survey.

Who are we working with?

Brecon Beacons National Park

Brecon Beacons Trust (funder)

Brecknock Wildlife Trust

Natural Resources Wales