Foxglove, scientifically known as Digitalis, is a stately plant prized for its tall, bell-shaped flower spikes, making it a favorite in cottage gardens. Most common varieties, like Digitalis purpurea, are biennials, meaning they establish a low rosette of leaves in the first year and flower in the second, after which they typically die back. Pruning the plant is a fundamental garden practice that maintains its health, extends its aesthetic appeal, and allows control over its life cycle and aggressive self-seeding. By understanding the plant’s growth habit, a simple cut can redirect its energy, maximizing the number of blooms or managing its spread.
Timing the Pruning Intervention
The success of pruning Digitalis hinges on acting immediately after the main flowering period, which usually occurs from late spring into early summer. The plant’s energy is instinctively focused on reproduction, so the goal is to intervene before the spent flowers fully transition into mature seed capsules. This window of time is when the plant is most susceptible to being “tricked” into producing new growth instead of seeds.
For biennial types, a timely cut can sometimes stimulate smaller, secondary flower spikes, effectively extending the bloom season into mid-summer. Perennial foxglove species also benefit from this early pruning to encourage more robust growth and a better chance of returning the following year.
Deadheading for Repeat Blooms
Deadheading is the precise act of removing the spent primary flower spike to conserve the plant’s energy and force the development of new, smaller side shoots. Once the main flower stalk has bloomed and two-thirds to three-quarters of the bell-shaped flowers have faded, it is time to make the cut. Using clean, sharp shears, cut the primary spike back entirely, removing the main stalk down to a lower set of healthy leaves or just above a developing side shoot.
Making the cut redirects the plant’s stored energy away from forming hundreds of tiny seeds and into the production of smaller, lateral flower stalks. These secondary spikes offer an attractive second display that prolongs the flowering season, though they will not be as tall or dramatic as the original main bloom. This practice is most effective on short-lived perennial varieties and can sometimes trick biennial types into a longer bloom.
End-of-Season Cutback and Self-Seeding Control
The final pruning of the season focuses on controlling the plant’s population and tidying up the garden for winter. Foxglove is a prolific self-seeder; if the gardener desires a new crop of young plants for the following year, one or two of the spent flower stalks should be left standing. Allowing these stalks to dry and drop their numerous tiny seeds naturally will ensure the next generation of foxgloves is established nearby.
To prevent aggressive spreading, the final cut must be made before the seed capsules fully dry and split open. Cut the entire plant, including any remaining flower stalks and declining foliage, back close to the ground, leaving only the low basal rosette of leaves. Note that all parts of the Digitalis plant contain toxic cardiac glycosides, so wearing gloves when handling the foliage and stalks is a recommended safety precaution.