The Fireweed Family

One Of The Joys Of Late June Is The Opening Of The Pink Four Petalled Flowers Of The Willowherbs.

The flowers are all very similar but the plants themselves range from the small ones that eke out a living in cracks of the churchyard wall to the ones in unkempt areas of The Byes which are taller than me. In the wild they tend to prefer damp shady areas but several species have made themselves at home around the town.

We have nine different Willowherbs in the valley, eight are species of Epilobium, a name that translates roughly as ‘above the pod’ because the flower petals sit on top of the long narrow ovary. The odd one out is Rosebay Willowherb, Chamaenerion angustifolium, considered a different species because it has 2 petals larger than the others unlike Epilobium which has all four petals equal. It is sometimes called fire weed or bomb weed because it was so successful at colonising areas of burnt ground after large woodland clearances during the 20^th century and city bomb sites during and after World War II.

In the 19^th century, Rosebay Willowherb was not a common plant and it was not recorded in the Sid Valley by Dr Cullen in his Flora Sidostiensis of 1849. It is still restricted but there are large colonies behind St Francis’ Church in Woolbrook, up around Fire Beacon and White Cross, and in Salcombe Regis. Given the chance, it can become an invasive nuisance.

It probably arrived by train and this is linked to the common name Willowherb. When the elongated seed pods are ripe, they split open and each seed has a long white feathery ‘parachute’ rather like willow seeds, and it allows the seed to travel great distances. The turbulent air along railway lines has helped it spread from its original woodland home and it is very common on railway embankments.

Rosebay Willowherb is easy to identify, the smaller species not so, the flowers are very similar with a long pod bearing four pink petals. You have to look for tiny differences in the shape of the flower’s stigma or the arrangement of the hairs on the stem to tell some apart. That matters to botanists but we can just say it’s a Willowherb and that will do.

As the name suggests, Great Willowherb is the largest UK species and it can grow to nearly 2m or six feet tall. The scientific name, Epilobium hirsutum, means Hairy Willowherb and it is, but not as hairy as the much smaller Hoary Willowherb which is clothed in a dense grey coat of hairs. This is the one you are most likely to see growing in the cracks of the churchyard wall. The dense hairs help it to retain precious moisture.

Great Willowherb has the old name codlins and cream or apple pie. Codlins are an old cooking apple variety and the flowers of the Great Willowherb are supposed to be apple pink with a splodge of cream in the centre, I’ll let you decide. However, the flowers are a great favourite with many insects and are included in the RHS list of plants for pollinators. The leaves are one of the food plants for the very impressive caterpillars of the Elephant Hawk Moth.

Another Willowherb not found by Dr Cullen is now one of the most common in Sidmouth. With its much branched red stems, American Willowherb was first recorded in the UK in 1891 and now it is growing in many of the cracks at the base of walls around town.

Most of them are very small, but well worth a closer look.

Ed Dolphin