From our perspective as Calla Lilies (Zantedeschia spp.), we are expressive plants that communicate our health and needs through our foliage and, most importantly, our iconic flower spathes. When we fail to produce these flowers, it is a clear sign that our fundamental requirements are not being met. Here are the primary reasons from our point of view.
We require abundant, bright, indirect light to manufacture the sugars necessary for flower production. If we are placed in a location that is too shady, our photosynthetic processes are limited. We can only produce enough energy to sustain our lush foliage, leaving nothing in reserve to create a flower stalk. While we appreciate protection from harsh, direct afternoon sun that can scorch our leaves, a few hours of gentle morning or late afternoon direct light is immensely beneficial for triggering bloom development.
Our life cycle includes a crucial dormant period. After our flowering season, we need a time of rest where we can recuperate and store energy for the next bloom cycle. If you continue to water and fertilize us heavily year-round, you disrupt this natural cycle. We never get the signal to slow down and subsequently, we lack the stored energy to produce a flower. We require a period of reduced watering and no fertilizer after our flowers fade and our leaves begin to yellow naturally.
The type of food we receive is critical. A fertilizer high in nitrogen (the first number on the package) will encourage us to produce an abundance of beautiful, dark green leaves at the expense of flowers. Nitrogen promotes vegetative growth. To initiate blooms, we require a fertilizer that is higher in phosphorus (the middle number), which promotes root development and flower formation. An imbalance tips our energy allocation away from reproduction (flowering) and toward pure vegetation.
Our rhizomes need the right amount of space. If we have been left in the same container for too long, we can become extremely pot-bound. This extreme crowding stresses our root system and leaves us competing for limited resources, inhibiting our ability to flower. Conversely, if you have recently divided our rhizomes, you may have been too enthusiastic. A division that is too small, with few growth eyes, will spend one or two seasons regenerating its root and leaf system before it has enough energy to flower again.
If we are a young plant grown from a seed or a very small division, please be patient. We must reach a certain level of maturity before we can begin the energetically expensive process of flowering. Our focus in the first year or two is on establishing a strong root system and healthy foliage. Similarly, if we have been recently repotted or transplanted, even if done correctly, our energy is directed into settling into our new environment and growing new roots, which can temporarily delay flowering.
Our water needs change throughout our growth cycle. During our active growth and flowering period, we prefer consistently moist soil. However, waterlogged, soggy soil will suffocate our roots, causing stress and rot, which makes flowering impossible. Conversely, allowing us to dry out completely during our growth phase creates significant stress and can cause us to abort any developing flower buds in an attempt to conserve resources.
