Chickweed Willowherb, Epilobium alsinifolium

 Chickweed Willowherb, Epilobium alsinifolium.

I have been taking photos of Willowherbs this year and a trip up to Upper Teesdale in early August raised the possibility of seeing two northern species, Alpine Willowherb ( Epilobium anagallidifolium) and Chickweed Willowherb ( Epilobium alsinifolium). Both occur at high altitude and are given full page coverage in Margaret E. Bradshaw's book 'Teesdale's Special Flora', published in 2023. In addition both species have been added to the Second Edition of Harrap's Wild Flowers which has been extended in a very useful way and is the best field guide due to its 'Detail' information. 

Alpine Willowherb is very much at its southern limit at Teesdale and it is a very rare plant with few recent records. Chickweed Willowherb is more frequent and has wider altitudinal range and even occurs further south in Snowdonia.  

Anyway I set off to see both and was lucky to find the more frequent species.

6th August 2025. 

As I walked up the steep hillside I spotted a damp area highlighted by pale green moss in which were a lot of Willowherbs. Up to that point I had only seen Marsh Willowherb, which were easy to identify due to their narrow leaves, but these plants looked very different with very wide leaves.

Typical Willowherbs flowers at the tip of the long seed capsule.

The problem was then to confirm the identification which was not easy. Both have a club-shaped stigma. Both have leaves that are hairless. Stems sparsely hairy in 2 rows for both, plus a lot of overlapping features like fruits 2-4cm long in Alpine and 3-6cm in Chickweed.  Flowers variably glandular-hairy on base of flower and fruit for Chickweed vs. a few glandular hairs on base of flower and fruit for Alpine. Clearly not a lot to go on here in terms of distinguishing features. 

Without any previous experience of either species I checked the books mentioned above. The main difference as noted in Teesdale's Special Flora, is that Alpine has yellowish-green leaves, tapered at both ends, unlike Chickweed Willowherb which has bluish-green leaves and have a rounded base with a distinct stalk. The colour difference does not appear to be strong in the example photos in either book.

Alpine Willowherb has leaves 1-2.5mm long described as elliptical-lanceolate, tapered at both ends, entire or faintly and distantly sinuate-toothed. Gradually narrowed below into a short, stalk-like base.

Chickweed Willowherb has leaves 1.5-3mm long described as ovate to ovate-lanceolate, distantly sinuate-toothed, rounded at base, petiole short.

Since elliptical means widest in the middle and ovate means broadest towards the base it would seem that the photo above shows the correct leaf shape for Chickweed Willowherb. This is backed up by the clearly toothed margins.

Chickweed Willowherb leaf, 6th Aug 2025.

Flower , none were open that afternoon.

Some patent glandular hairs on calyx and capsule.

Mid stem showing curved non-glandular hairs although the '2 rows' are not that clear.

It would appear that patent glandular hairs are frequent on upper stems but lower down are replaced by curved non-glandular hairs with both types present on upper stems. Strangely although the literature says the leaves are hairless, some tiny glandular hairs were present on the leaf margin.

The site I visited had a previous record for both rare willowherbs but I only found Chickweed on this visit. I think I was lucky to find one species as the damp stream bed was the only place where these were present. Marsh Willowherb ( Epilobium palustre) was common in the area with its narrow leaves.  

Marsh Willowherb ( Epilobium palustre) Narrow leaves with downturned margins.

Marsh Willowherb, with patent glandular blunt hairs plus curved tapered hairs. 6th Aug 2025

Always great to find a target species.

Peter Leonard, 

November 2025