Calla lilies, known scientifically as Zantedeschia, are highly prized in floral arrangements for their sleek, architectural forms and vibrant colors. The distinctive funnel-shaped bloom, called a spathe, lends an air of modern elegance to any setting. Successfully transitioning these beautiful flowers from the garden to a vase requires specific harvesting and care techniques to ensure their longevity.
Identifying the Best Time to Harvest
The stage of maturity when a calla lily is harvested directly dictates its vase life. The optimal time to cut is when the spathe, the large colored leaf, is fully unfurled or has just begun to open. Harvesting at this stage ensures the bloom will continue to mature slowly rather than wilting prematurely. Wait until the central structure, known as the spadix (the yellow spike within the spathe), is visible but not fully exposed. Cutting the flower when the plant is fully hydrated also maximizes post-harvest success, making the early morning or late afternoon the best time for harvesting.
Making the Initial Cut
Once the ideal bloom stage is identified, the cutting method must prioritize clean entry and maximum water absorption. Use a very sharp, clean cutting instrument, such as a floral knife or bypass shears, to make the initial cut; dull tools crush the stem cells and prevent efficient water uptake. The cut should be made swiftly at a 45-degree angle close to the base of the plant, near the soil line. This angle increases the surface area for better hydration and reduces the likelihood of the stem base resting flush against the bottom of the vase, which could block water flow.
Immediate Post-Harvest Conditioning
The moment the stem is severed, immediately place it into a container of water, as the cut surface begins to seal rapidly. Calla lilies contain a thick, milky sap that leaks from the cut end and can quickly clog the vascular tissues responsible for drawing water up the stem. To counteract this, the stems require a process known as “hardening” or a deep drink. Place the freshly cut lilies into a tall vessel filled with cool, clean water for two to four hours in a cool, dark location, allowing them to fully saturate. During this conditioning phase, use a commercial flower food mixed into the water; this provides a biocide to inhibit bacterial growth and a carbohydrate source for energy, which is essential for extending the time the flowers remain fresh.
Extending Calla Lily Vase Life
Once the calla lilies are conditioned and arranged, continuous maintenance is necessary to maximize their elegance. The water in the vase should be completely changed every two days, and the container thoroughly cleaned to remove any bacterial film. Each time the water is changed, the bottom one-half inch of the stem should be removed using a fresh, angled cut. This action eliminates any material that has started to clog the water-conducting tissues and allows the stem to continue drawing up fresh water and nutrients efficiently. Position the vase away from direct sunlight, heat sources, or drafts, and avoid placing the arrangement near ripening fruits, which release ethylene gas, a plant hormone that signals flowers to prematurely age and wilt.