The common foxglove, a plant belonging to the genus Digitalis, is widely recognized for its stately, bell-shaped flowers. The direct answer to whether it blooms every year is usually no, because the most common species, Digitalis purpurea, is a biennial plant. This means the plant’s life cycle spans two years, with flowering occurring only in the second year of growth. However, certain cultivated varieties have been bred to flower in their first year, and gardeners often employ techniques to create the appearance of continuous annual blooms.
Understanding the Foxglove Life Cycle
The biennial nature of the foxglove dictates its flowering schedule across two distinct growing seasons. In the first year, after the seeds germinate, the plant focuses entirely on vegetative growth, forming a low-lying, dense cluster of leaves known as a basal rosette. This rosette captures sunlight and stores energy throughout the first season.
The plant then requires a period of cold, a process called vernalization, to trigger the hormonal changes necessary for flowering. After surviving the winter, the stored energy is used in the second year to produce a tall, upright flower stalk, a process known as bolting. This spike can grow several feet high and is covered in the iconic tubular flowers. Once the flowers are pollinated, they set seed, and the plant dies.
While Digitalis purpurea is a true biennial, some species like the yellow foxglove (Digitalis grandiflora) are shorter-lived perennials, meaning they may flower for several years. Also, some modern cultivars, such as the ‘Camelot’ or ‘Dalmatian’ series, have been specifically bred to be first-year flowering, essentially behaving like annuals. These distinctions are important when selecting seeds or plants.
Techniques for Continuous Annual Blooms
Despite the typical biennial life cycle, gardeners can successfully cultivate a patch that appears to bloom annually. This illusion is achieved through the plant’s natural tendencies combined with gardener intervention. Foxgloves naturally produce an abundance of tiny seeds that readily drop to the ground around the parent plant.
This process, known as self-seeding, ensures new first-year rosettes are constantly establishing themselves near older, flowering plants. By allowing some flower spikes to mature and drop seeds, a gardener creates a staggered population where rosettes and flowering spikes are present simultaneously. The biennial plants that flowered will die, but the new rosettes will be ready to bloom the following year, perpetuating the cycle.
Another effective method is staggered planting, which involves sowing seeds or planting young rosettes in successive years. For example, sowing a batch in Year One and another in Year Two guarantees that a portion of the plants will be in their second, flowering year every season.
Deadheading
Deadheading, the removal of spent flowers, can sometimes encourage a biennial plant to put out a few secondary, smaller blooms. However, if the goal is to maintain a continuous naturalized patch, a few seed stalks must be left intact to ensure the next generation of rosettes is established.
Safety Considerations and Toxicity
All parts of the foxglove plant are poisonous if ingested, including the leaves, flowers, seeds, and even the water in which cut flowers have been placed. This toxicity is due to the presence of potent compounds known as cardiac glycosides, such as digitoxin and digoxin. These substances can directly affect the rhythm and force of heart contractions, which is why derivatives from the plant are used in modern medicine to treat certain heart conditions.
Accidental ingestion can lead to severe poisoning, with symptoms that include nausea, vomiting, stomach pain, headache, and visual disturbances. More dangerously, ingestion can cause cardiac irregularities, including a slow or irregular heartbeat, which can be life-threatening. Gardeners should always wear gloves when handling foxglove, especially when pruning or harvesting seeds, to avoid skin irritation. Clear warnings should be established for children and pets to prevent accidental consumption.