The native foxglove, Digitalis purpurea, is well known and immediately recognisable. In cottage and woodland gardens, drifts of tall and slender spires of foxglove blossom create a dreamy, reaching-for-the-sky effect. Outwith garden settings, they can be seen on verges of country lanes, steep slopes of railway banks, or newly exposed urban waste ground. Whether carefully planted for special effect in gardens, or growing as self-sown seedlings, foxgloves are always a cheerful sight in late spring and early summer.
Large groups of naturally occurring foxglove seedlings produce plants with flowers in shades of purple and lilac, but very often a few white flowers appear amongst them. The native white-flowered forms have been specially cultivated for many years by horticulturists and seed companies, and as a result, seed of white foxgloves is readily available, usually under the botanical name of Digitalis purpurea f. albiflora.
Native foxgloves are biennial, which means that seed sown now will produce plants that will flower around this time next year. Scattering seed on freshly cultivated soil is the natural approach, but when planning a show of white foxgloves, I prefer to have a little more control. I sow seed in late May or early June on the surface of a pot of moist, multi-purpose compost which is then well-watered and placed in a shady spot, usually tucked in a corner of the cold frame. The seed doesn’t take long to germinate, and as soon as seedlings are large enough to handle, I prick them out into individual 10 cm pots and grow them on for a few weeks in the cold frame. They grow quickly, and when plants have decent root systems and robust foliage, they can be planted out in groups in their final positions. It is important to make sure they are planted before the end of August so they have time to develop strong root systems before autumn. Using this method, you can be assured of a fine display of spires of white flowers towards the end of the following spring.
Once newly introduced white foxgloves have flowered in your garden for the first time, they will probably self-seed and return in following years. If purple-flowering plants are growing in close proximity, you will probably find that, each year, there will be more seedlings producing purple flowers, and fewer with white flowers. This is because biennial species of foxgloves interbreed very easily, and reversion to purple blossom can occur quickly. I manage to keep a good supply of white foxgloves in the garden, but this is only because I keep removing the plants with purple flowers as soon as I spot that developing buds are going to produce purple, rather than white, blossom. Fortunately, bumblebees seem to be happy with the white foxgloves; had they bypassed the white flowers and shown a preference for purple flowers, then I would have rethought my cultivation methods.
Foxgloves are tolerant of a wide range of conditions but prefer semi-shade or sunshine in moist, well-drained soil. They grow best where they have little competition from surrounding plants, and as many gardeners well know, they love to make their home, often randomly and unexpectedly, in gravel paths, raised beds and rock gardens.