Although I’d never heard of it until I came to RHS Garden Harlow Carr, once discovered, Digitalis ferruginea instantly became the best foxglove I’d ever seen – and I can’t imagine that will ever change.
In the first year from a seedling it creates a deep green, mound-like rosette of slender evergreen leaves. These look so striking when several different stages grow together in a group. From the second year onwards, the most impressive ramrod-straight flower spikes begin to emerge from the centre of the rosettes, sometimes reaching a lofty 1.5m (5ft). These are clothed in golden-bronze flowers that last for weeks on end and are abuzz with bees.
After the flowers have faded, the spires become towering seed columns. They ripen as the season progresses, eventually turning a deep, brownish-black. When the seed is ripe the plants become a great source of food for birds.
The spires stand all winter, unharmed by the severest of weather. They add a dramatic and architectural element to the Main Borders, where most of ours are planted. They're so striking in the winter months that I've even added a few to the Winter Walk where they'll act as dark silhouettes against the fiery Cornus sanguinea ‘Midwinter Fire’.
Like all foxgloves, Digitalis ferruginea will seed freely and has a tendency to pop up where it likes. It doesn't necessarily stay where you intended it to be, often leading to some fantastic combinations that even the most skilled plantsman probably wouldn’t contrive.