The Tees to High Force

Fresh from our recent visit to Falcon Clints, last week, I had the pleasure of returning to Upper Teesdale – this time as part of the Botanist’s Year course I’m leading for the Natural History Society of Northumbria. This walk was a little less strenuous than our previous outing and took us from Bowlees, past Low Force, and on to the spectacular High Force waterfall. Along the way, we encountered a variety of fascinating plants and as ever, this blog will list just a few of the highlights.

One of the things I adore most about Teesdale is the abundance of Globeflower Trollius europaeus. There is just something about these plump, yellow, spherical blooms that makes me feel inextricably happy. Perhaps that joy comes from the plant’s tendency to grow in particularly special places, often in rugged upland areas?

Closely associated with limestone, Globeflower favours damp, open habitats along rivers and on mountain slopes. Along the Tees, it is remarkably abundant, and almost as soon as we reached Low Force, we were treated to a fine display.

Having spent more than enough time admiring the Trollius, we soon set off along the banks of the Tees. In these early stages of the walk, we encountered several other interesting plants, including Rock Whitebeam Sorbus rupicola and Dark-leaved Willow Salix myrsinifolia, two of the area’s more notable trees. We also came across several more commonplace species including Bitter-vetch Lathyrus linifolius and Wood Crane’s-bill Geranium sylvaticum.

Far more striking during these early stages were the orchids, which, thanks to some long-overdue rain, were now flourishing. Early-purple Orchids Orchis mascula are usually plentiful along the riverbanks here, but most (aside from the fine specimen below) were now past their best. In their place, the summer species were beginning to take over, including a large population of Heath Spotted-orchid Dactylorhiza maculata and several smaller populations of Northern Marsh-orchid Dactylorhiza purpurella.

We also observed signs of hybridisation between the latter two species, which had produced several pale-pink, intermediate specimens. These may well turn out to be the hybrid Dactylorhiza × formosa, though I’m not entirely certain. Orchids are a rather difficult bunch…

Orchids aside, the banks of the Tees are an excellent place to spot all manner of colourful and interesting plants, including several of the area’s specialities. On our way to the midpoint at Holwick Bridge, we were pleased to encounter Common Butterwort Pinguicula vulgaris, Alpine Bistort Bistorta vivipara, and a handful of Bird’s-eye Primrose Primula farinosa that had not yet gone over.

Arguably more interesting during this leg of the trip were several superb examples of Shrubby Cinquefoil Dasiphora fruticosa. A species of damp rock ledges and riverbanks subject to periodic flooding, this is an incredibly rare native plant whose distribution maps are distorted by escapes from cultivation. In fact, it is more commonly encountered as a garden escapee – often from supermarket car parks – but in the wild, it occurs in Teesdale and just a select few other locations. With its vibrant yellow flowers, it is quite the attractive plant.

As we neared Holwick Bridge, several more noteworthy plants caught our attention. First came a lovely brace of Common Twayblade Neottia ovata – not the most eye-catching of orchids, I admit – and later, an exciting duo of horsetails. Wood Horsetail Equisetum sylvaticum was easy to spot thanks to its distinctive, feathery branches. The second, Shady Horsetail Equisetum pratense, took a bit more effort to identify.

Once you get your eye in, it has a fairly distinctive appearance, with its branches swept to one side in a somewhat Trump-esque fashion. It is an uncommon plant in England, with the majority of the national population found in Scotland.

In the near area, we also encountered a flowering patch of Common Bistort Bistorta officinalis.

Beyond the bridge and onwards towards High Force, the flora began to shift, with lush riverside vegetation gradually giving way to Juniper Juniperus communis scrub. It was disheartening to see that many of the junipers were blighted by disease – presumably the much-maligned Phytophthora austrocedri. Still, despite this, we were pleased to spot some cheerful Mountain Pansies Viola lutea, and the scenic views were certainly not to be scoffed at.

The surroundings of High Force itself proved interesting, particularly due to the variety of ferns present. While we didn’t manage to find the hoped-for Mountain Male-fern Dryopteris oreades, we did come across some fine examples of Narrow Male-fern Dryopteris cambrensis. Better still was Lemon-scented Fern Oreopteris limbosperma, with its distinctive tapering fronds and subtle citrus aroma.

We also found some attractive Beech Fern Phegopteris connectilis, and a brief look at the insect life proved rewarding. A fleeting glimpse of a Broken-belted Bumblebee Bombus soroeensis – sadly too quick for a photo – was followed by several rather more obliging Gypsy Cuckoo Bumblebees Bombus bohemicus.

After saying our goodbyes to the group, Matt and I decided to make the most of the day by setting out in search of yet more ferns (by this stage, you may be noticing a bit of a trend this year). High on our agenda was an abandoned quarry on the opposite bank of the Tees, not far from the paid entrance to High Force.

Following in the footsteps of John Durkin, who recorded several interesting species here in 2023, we set about exploring the quarry walls – and were rewarded with some noteworthy finds.

Among the more common ferns were Wall-rue Asplenium ruta-muraria and Maidenhair Spleenwort Asplenium trichomanes subsp. quadrivalens. More exciting, at least for this budding pteridologist, were Rustyback Asplenium ceterach and Delicate Maidenhair Spleenwort Asplenium trichomanes subsp. trichomanes – two species I see far too infrequently for my liking.

Among the larger ferns, one in particular caught my eye due to its noticeably extended dark blotches at the junction of the costa and the rachis. My hunch was that this might be a new species for us – Alpine Male-fern Dryopteris lacunosa – however, as I wasn’t yet fully familiar with the species, we chose to leave it unidentified for the time being.

Happily, once photos were shared with John Durkin, he appeared to confirm my suspicion. We’ll need to check in again to be sure, but this could well represent the first record of D. lacunosa for Upper Teesdale – how exciting, and what a fitting note on which to end this little blog.

For those interested, I share further musings on Dryopteris lacunosa [here].