Foxglove plants (Digitalis) are highly valued for their striking vertical presence and unique, tubular blossoms. These imposing spires of flowers, which can reach heights of up to six feet, introduce a dramatic element to landscapes. The pendulous, bell-shaped blooms typically feature intricate spotting inside the throat, attracting pollinators like bumblebees and hummingbirds. Understanding the bloom period and the plant’s growth pattern is necessary for successfully incorporating this ornamental into a garden space.
The Primary Bloom Schedule
Foxglove’s main flowering display typically begins in late spring and continues into early summer, generally spanning from late May through July. The tall flower spikes offer several weeks of color before the individual flowers fade. As the blooms mature, they open sequentially, starting from the bottom of the spike and progressing upward toward the tip. This staggered opening allows the overall floral show to last longer on a single stalk. The length of the display can vary based on local climate, with cooler regions often experiencing a slightly extended flowering period.
Understanding the Foxglove Life Cycle
The bloom schedule is directly tied to the life cycle of the most common variety, Digitalis purpurea, which is classified as a biennial. In its first year, the plant establishes itself by forming a low-growing, basal rosette of woolly leaves. This vegetative stage focuses on developing a robust root system and storing energy, and no flower stalk is produced. The plant must undergo a period of cold temperatures, known as vernalization, to trigger the flowering process.
The second year, the plant “bolts,” sending up the characteristic tall flower spike. After the flowers bloom and the plant sets seed, the biennial variety completes its life cycle and dies. However, some types are true perennials, such as Digitalis grandiflora or the hybrid Digitalis x mertonensis, which will bloom annually for several years. Additionally, certain cultivars have been bred to bloom reliably in their first year from seed, essentially behaving as annuals.
Extending the Display and Encouraging Rebloom
Gardeners can influence the duration of the foxglove display through deadheading, which involves removing the spent flower spikes. Cutting down the main spike once it has finished blooming prevents the plant from putting all its energy into seed production. This action can redirect the plant’s resources to produce smaller, secondary flower spikes that emerge from the base or side shoots. These secondary blooms, while not as dramatic as the primary spire, can extend the overall color in the garden by a few weeks into mid-to-late summer.
Timing this process is important because if the gardener wishes to maintain a continuous presence of the biennial type, some flower spikes must be left to mature. Allowing the last one or two spikes to set seed ensures that the plant can self-sow, dropping seeds that will grow new basal rosettes for the following year’s bloom. This cycle of self-seeding allows Digitalis purpurea to appear to be a perennial in a garden setting, even though the original plant dies after its second year. Deadheading also helps manage the plant’s aggressive self-seeding habit in areas where its spread is unwanted.
Important Safety Considerations
Despite its ornamental appeal, all parts of the foxglove plant are highly toxic if ingested by humans or pets. The plant contains potent compounds known as cardiac glycosides, with the most notable being digoxin and digitoxin. These chemicals are the origin of a powerful heart medication, but in uncontrolled doses, they profoundly affect the heart’s function.
Ingestion can lead to serious cardiac symptoms, including various arrhythmias, heart block, and an irregular or slow pulse. Other signs of poisoning may include nausea, vomiting, confusion, and visual disturbances. Because of this severe toxicity, it is important to exercise care when handling the plant, and wearing gloves is recommended. If accidental ingestion occurs, immediate medical attention is necessary, and contacting a poison control center is the first step.