Telling Woods from the Trees

Whispers of the Wildwood: Spotting the Plant Indicators of Britain's Ancient Woodlands

There is no real ‘ancient’ woodland in the immediate Sidmouth area although some does occur in the wider Sid Valley. Whilst no ancient woodland survives around the town itself one can encounter remnants of a lost wooded past.

While historical maps and archaeological features like wood banks offer valuable clues, some of the most reliable storytellers are the plants growing beneath the canopy. Known as ancient woodland indicator species, these are plants that do not colonise new areas easily and rely on the stable, relatively undisturbed conditions of a mature canopy to survive. 

Step into an ancient broadleaf woodland in spring, and you are stepping into a living time capsule. These irreplaceable ecosystems—defined in England as areas that have been continuously wooded since at least 1600 AD—are often described as Britain's equivalent of the rainforest. They have had centuries to develop complex structures and host a rich, diverse web of life, particularly rare or specialised species. 

Let us explore some of the most iconic plant indicators you can spot on a woodland walk. If you encounter some of these plants then you may have found an area that was, until fairly recent times, woodland of a truly ancient nature. 

The Sluggish Colonisers of the Forest Floor

Many ancient woodland indicators are remarkably slow to spread. Without the help of vigorous wind-dispersed seeds, they rely on underground networks or specialised growth habits that require decades to cover even a small patch of ground.

• Wood Anemone (Anemone nemorosa): Also known as the Windflower, this delicate plant features floppy white flowers that burst into bloom in early spring. They take advantage of the abundant light on the forest floor before the tree canopy opens and casts its deep summer shade. Because Wood Anemones spread via underground rhizomes that grow incredibly slowly, a large carpet of them is a strong signature of an ancient, undisturbed wood.

• Dog's Mercury (Mercurialis perennis): This unassuming green herb often forms dense, carpet-like stands on the woodland floor, particularly in calcareous (lime-rich) soils. Like the Wood Anemone, it is a classic indicator that does not travel quickly, making it a reliable marker of ecological continuity.

• Wood Sorrel (Oxalis acetosella): With its bright green, clover-like leaves and delicate white flowers, Wood Sorrel is another shade-loving specialist of mature woodlands. Interestingly, while it is a strict ancient woodland indicator in southern Britain, in the cooler and wetter north and west it can sometimes be found growing outside of woods, as the damp climate compensates for the lack of tree shade.

A Symphony of Spring Colour

A classic image of ancient woodland is a vibrant, colourful carpet of spring flowers. Some of our most beloved woodland blooms are actually indicators of these historic landscapes.

• Native Bluebell (Hyacinthoides non-scripta):The quintessential spring spectacle. Under the dappled light of newly opened spring leaves, native bluebells nod gracefully on one side of their delicate stems, filling the air with a heavy, sweet perfume. However, our native bluebell faces a serious modern threat from the Spanish Bluebell (Hyacinthoides x hispanica), a more robust garden escape with upright stems and flowers all around. The two hybridise readily, slowly diluting the native gene pool.

• Yellow Archangel (Lamiastrum galeobdolon): This member of the deadnettle family boasts striking, hooded yellow flowers and is typically found in mature woods and ancient hedgerows. Like its fellow indicators, the native species is under threat from an invasive, variegated garden escape with silver-blotched leaves that smothers native flora.

Damp Glades and Shade Specialists

In wetter woodlands, such as the boggy combes and valleys where springs emerge, a different suite of ancient indicators takes over.

• Opposite-leaved Golden-saxifrage (Chrysosplenium oppositifolium) & Yellow Pimpernel (Lysimachia nemorum): These low-growing, moisture-loving plants thrive in wet, shaded flushes and alongside pristine woodland streams, offering a bright splash of gold to damp woodland hollows.

• Ramsons or Wild Garlic (Allium ursinum): Walking through a damp ancient wood in late spring, you will often smell Ramsons before you see them. Their broad, tulip-like leaves and starry white flower clusters blanket damp woodland floors, releasing a rich garlic aroma that is a favourite of foraging humans and waking bears alike!

The Canopy and the Floor

It is not just the ground flora that points to an ancient past; the very trees above us and the ferns below have stories to tell.

• Small-leaved Lime (Tilia cordata) & Wild Service-tree (Sorbus torminalis): These trees are highly indicative of ancient woodland sites. Because our modern climate is too cold for them to reliably produce fertile seeds, they reproduce primarily by "suckering"—sending up clone shoots directly from their ancient root systems. Spotting these species is a powerful clue that the woodland canopy has remained intact for centuries.

• Ancient Ferns: Non-flowering plants are also valuable indicators. The presence of slow-growing species such as Soft Shield-fern, Hard Fern (Blechnum spicant), and Scaly Male-fern (Dryopteris affinis) clinging to old hedge banks or damp slopes testifies to the long-term humidity and shelter of an ancient woodland habitat.

The Nature Historian

For centuries, these woodland plants have co-existed with human activity—managed through traditional practices like coppicing, which temporarily opens the canopy to let light in and trigger a spectacular "flush" of these spring flowers. 

Today, only about 2% of the UK is covered by ancient woodland, and many of these sites are small, fragmented, and vulnerable to development, pollution, and invasive species. Identifying just one indicator plant is a thrill, but finding a rich tapestry of them means you are standing in a place that has been, or historically has been, continuously wooded for over four hundred years—a true sanctuary of nature.