14 May 2015

Some aliens along the River Neath

The River Neath and its riparian woodland

The narrow corridor of deciduous woodland that runs along the River Neath from Glyn Neath to Neath town is an extremely important habitat for wildlife in Neath Port Talbot. It is rich in ancient woodland species and one of the few places in the county where you can see native Primrose (Primula vulgaris) growing with Wood Anemone (Anemone nemorosa), Wild Garlic (Allium ursinum), Dog's Mercury (Mercurialis perennis), Sanicle (Sanicula europaea) and Bluebell (Hyacinthoides non-scripta) under the occasional canopy of Small-leaved Lime (Tilia cordata). Once upon a time, this narrow strip of riparian woodland, dominated by Wych Elm (Ulmus glabra), would have occupied a much wider margin that is currently taken up by grazed, alluvial meadows. 
Among the desirable natives, a number of infamous, high impact aliens well known to all of us, such as Japanese Knotweed (Fallopia japonica) and Himalayan Balsam (Impatiens glandulifera), have colonised the riparian corridor aggressively in the last 75 years. More recent exotics include the Spanish Bluebell hybrid (Hyacinthoides x variabilis), which in my experience is much more common than pure Spanish Bluebell (both are sold and grown as garden plants), and Montbretia (Crocosmia x crocosmiiflora), a classic garden throw-out species. Cotoneaster species and Wilson's Honeysuckle (Lonicera nitida) are also represented.
Less common aliens which have become well established include Star-of-Bethlehem (Ornithogalum umbellatum subsp.umbellatum).

Star-of-Bethlehem, Riparian Woodland Glyn Neath

This attractive plant has become well naturalised in the riparian woodland near Glyn Neath, growing among the Wild Garlic and Bluebells. Nearby, there are some colourful patches of Greater Periwinkle (Vinca major Var. major) and a well established clump of Chinese Holly-fern (Cyrtomium falcatum).

Greater Periwinkle,Riparian Woodland Glyn Neath

Chinese Holly-fern, Riparian Woodland Glyn Neath

Star-of-Bethlehem and Greater Periwinkle are hardy garden plants, adapted to the rigours of the British climate and their occurrence as 'garden escapes' in our countryside is not particularly surprising.  But, the occurrence of Chinese Holly-fern doing so well here is fascinating, because it is usually grown indoors as a pot plant. It is a native of East Asia which requires warm, moist conditions to grow. It has been established as a wild plant in the mild climate of the Scilly and Channnel Isles for many years.  It will be interesting to see if  it will be able survive in Glyn Neath in view of the harsher winters that may accompany the new, forthcoming El NiƱo cycle. 

3 comments:

Ian Morgan said...

An interesting post as always Charles, and the common escapees/`chuck-outs` that you mention are common too to neighbouring Carmarthenshire (eg Montbretia, Lonicera nitida - which roots so easily from discarded cuttings - and the periwinkles). I had a (planted) Chinese holly-fern in my garden and it was hit hard by those recent very cold winters that we had, though it has re-grown, so perhaps it is tougher than we think. I did n`t know of `the new, forthcoming El Nino`... cycle - what`s going to happen? Do I need to get my long-johns ready?

Charles Hipkin said...

Who knows Ian, probably more rain for us......but keep the long-johns handy and look out for Carmarthen's first snowy owl!

Charles Hipkin said...

Correction... Carmarthen's second Snowy Owl!!!