Whitebeams & Wildlife of the Western Hills

Arran is home to three species of tree which do not occur anywhere else in the world, the Arran Whitebeam (Hedlundia arranensis), Cut-leaved Whitebeam (Hedlundia pseudofennica) and Catacol Whitebeam (Hedlundia pseudomeinichii). This walk gives an opportunity to learn about these trees, some of rarest in the world, as well as experiencing a range of mountain wildlife.
We are thrilled that one of our guides will be a staff member from the Royal Botanic Garden Edinburgh, whose Scottish Plant Recovery Project is aiming to restore ten threatened native Scottish species in the wild, including Arran’s three endemic trees.

Overview
Distance:  16km

Highest point gained:  Beinn Tarsuinn (527m)

Total Ascent: 715m

Walk duration:  7hrs

Terrain:  Rough mountain paths, some pathless, wet and tussocky moorland, some  steep sections
Technical Rating: Moderate

Endurance Rating:  2
Cost:  £25

Date:  Friday 15th May 2026

Meeting time:  08.45 Meeting place:  Festival Hub at the Auchrannie Playbarn.  Transport to the start & finish of  this walk is provided from there.

Walk description

Starting at Catacol, this route follows the path up Glen Catacol and into Gleann Diomhan, looking out for wildlife along the way.
In Gleann Diomhan some time will be spent chatting about the Arran Whitebeams, Scotland’s rarest native trees. Whilst the Arran Whitebeam was first recorded in 1897, the Catacol Whitebeam was only found as recently as 2007. In global terms, these trees are classed as dangerously close to extinction.
From the head of Gleann Diomhan, the route heads off-path and steeply up onto Beinn Tarsuinn, the highest point of the walk at 527m, and haunt of golden plover, birds of prey and red deer in the wild and remote western heart of Arran’s hills.
Continuing across boggy pathless terrain, the walk then descends to Loch Tanna, nestled under the scree slopes of Beinn Bhreac. Some early sundew and wispy cotton grasses may be encountered on its boggy shores. The route then rises again to reach the coll between Meall Bhig and Meall Bhreac before the descent to Coire Fhionn Lochan, a great place for a paddle on a sunny day.
Heading down the path from the lochan, wonderful views over to Kintyre and beyond can be enjoyed before reaching civilisation again at Thundergay.

This walk is organised by the Arran Mountain Festival, a Scottish Charitable Incorporated Organisation SC052229, supported by Auchrannie Leisure Ltd.