From the perspective of the plant, the foxglove (Digitalis purpurea) is a biennial or short-lived perennial. Its primary biological imperative is to flower, set seed, and reproduce. The towering spire of bell-shaped blooms is an evolutionary adaptation to attract its primary pollinators, bees. The speckled "landing pads" inside the throats guide insects deep into the flower to access nectar, ensuring effective pollen transfer. When you cut a flower spike for an arrangement, you are ultimately diverting a significant portion of the plant's reproductive energy away from seed production. For a biennial species, this is a critical intervention, as the plant will die after flowering, making this its one chance to propagate.
To ensure the cut stems have the best chance of longevity, the plant's flowering stage is paramount. Harvesting should occur when the flowering spike has at least one-third to one-half of its florets open. The lower flowers will be fully open, with the middle ones swelling and the upper buds still closed but showing color. Cutting at this stage is ideal because the plant has allocated enough resources to the open flowers while the buds are still mature enough to continue developing using the stem's stored energy and water. Harvesting too early, when the spike is all tight buds, risks them never opening in the vase. Cutting too late, when most florets are spent, gives you a very short display as the plant's energy is already depleted.
The most critical consideration from the plant's own point of view is its potent chemical defense system. Foxgloves produce cardiac glycosides, such as digitoxin and digoxin, in all parts of the plant—leaves, stems, flowers, and seeds. These compounds are highly toxic to humans, pets, and livestock if ingested. This is the plant's primary mechanism for deterring herbivores. For the florist, this means handling the cut stems with care. Always wear gloves when cutting and arranging to prevent the sap from contacting your skin, which can cause irritation for some individuals. More importantly, it is absolutely vital to keep foxgloves out of reach of children and pets and to never allow any part of the plant to come into contact with food or drink. The sap can also leach into the vase water, so be cautious when disposing of it.
Once cut, the foxglove stem's needs are simple: hydration and a clean environment. Recut the stems at a 45-degree angle underwater or immediately before placing them in water to prevent an air embolism from blocking the vascular tissue (xylem), which would hinder water uptake. The plant's vascular system is its lifeline. Use a clean vase and fresh water, potentially with a floral preservative. The preservative provides sugars (energy the plant would normally get from photosynthesis), acidifiers to stabilize the water's pH, and biocides to prevent the growth of bacteria and fungi that would clog the stem and accelerate decay. Place the arrangement in a cool location away from direct sunlight and ripening fruit, which emits ethylene gas that accelerates aging in cut flowers.
