by Ian Brand

ALMOST without noticing, spring has been left behind; the Bluebells and Ramsoms have set seed and the House Martins have returned to our eaves.

Early summer has arrived and what better symbol than the Foxglove? Suddenly growing rapidly, shooting skywards like a rocket taking off, producing a spike of pink-purple flowers.

The scientific name for Foxglove,Digitalis purpurea is well chosen from the Latin (digitus) meaning finger or digit. The tubular flowers are the right size and length to fit over the end of a small finger. The flower is also an excellent fit for a bumblebee and these are the main visitors and pollinators. The flower narrows towards the base so the bumblebees need to poke their tongue out to reach the nectar. As a result, the flowers are much visited by long-tongued bumblebees, especially the garden bumblebee and the common carder bee, with tongues extending up to 20mm (that’s more than the length of their bodies) compared to the honeybee’s more limited 9mm.

Foxgloves are biennials, taking two years to complete their life cycle. In the first year the plant produces a rosette of leaves close to the ground. They then need a cold spell or vernalization before they flower. During the second year the stem greatly elongates before producing a plethora of flowers. Each plant can set up to a million seeds by late summer, so it is no surprise it is one of our most common plants.

It was William Withering, in 1785, a physician from Birmingham who discovered the Foxglove’s medicinal use. Withering began to investigate its use when he examined a lady who was suffering from dropsy (now known as heart failure). He had expected her to die given the severity of her condition but on being given herbal tea from a friend, she made a dramatic recovery. He systematically investigated the active ingredient and discovered the foxglove responsible, although it was not until 1930 that digitoxin was isolated at The Wellcome laboratories.

A related compound digoxin was subsequently isolated from the Woolly Foxglove (Digitalis lanata), a native of Eastern Europe and found to be more effective and safer, and is today the drug of choice. The drug is still produced from the leaves of the Woolly Foxglove, one exception being during the Second World War when due to shortages the Women’s Institute were enlisted to gather large quantities of our native Foxglove.

Digoxin works by strengthening and slowing the heart rate and is now mainly used to treat Atrial Fibrillation (AF), which affects one million people in the UK rather than heart failure.

I end on a note of caution, Foxgloves are extremely poisonous because of their cardiac effects and should never be eaten or made into herbal tea.

www.wharfedale-nats.org.uk