Symphytum azureum

The Symphytum azureum, or blue comfrey, is a vigorous perennial and a must-have among medicinal plants. This variety stands out with its sky-blue to dark-blue flowers during spring. It will be ideal for dressing up your undergrowth, shaded areas, or damp soils.

Originally from the Caucasus, the blue comfrey has a creeping habit and a brittle stump. The plant quickly reaches 30 cm (12in) in height and 60 cm (24in) in width and is entirely covered with iridescent and prickly hairs at the base of the stems. Its abundant and honey-rich spring flowering displays multiple purple bells that evolve into sky blue to dark blue. At the end of flowering, the upright stems have a trailing appearance. Its semi-evergreen leaves are green and leathery, with oblong and lanceolate shapes and prominent veins. In shaded exposure, the leaves reach 20 to 25 cm (8 to 10in) in length. Its veined and green stems are intensely purple at the base.

Fast-growing Symphytum azureum is highly hardy. It spreads through robust stems called rootstocks and easily self-seeds.

In the garden, blue comfrey is a low-maintenance plant. It thrives in humus-bearing soils in partial to full shade but also does well in full sun if the soil is moist and humid. All cool areas of your garden will suit it. It is ideal for bordering flowerbeds, undergrowth, and riversides. With its rapid growth, you can pair it with bushes like rhododendrons or hydrangea and perennials like wild garlic or bellflower.

The blue comfrey gets its vernacular name from its ability to heal fractures and wounds. It is used in various fields, such as organic agriculture, as a "green" fertiliser, or as a strengthening plant for animals. It is also used in medicine due to its high content of vitamin B12.