From our perspective as calla lilies (Zantedeschia spp.), our primary purpose is to reproduce, and our magnificent, trumpet-shaped spathes are our method of achieving that. When we fail to produce these flowers, it is a sign that our fundamental needs are not being met. We are not being difficult; we are simply responding to our environment. Here are the primary reasons, from our point of view, why we may withhold our blooms.
We require a significant amount of energy to produce our large, showy flowers. This energy comes directly from the sun through our leaves. If we are placed in a location that is too dark or shaded, our photosynthetic processes slow down. We can only produce enough energy for basic survival—maintaining our foliage—and have nothing left in our reserves to initiate the complex process of flowering. We need bright, indirect light for most of the day to gather the necessary resources.
Many of us, particularly the colored hybrids, require a distinct annual cycle of growth and rest. After our flowering period, we need a period of dormancy. This is often triggered by shorter days and cooler temperatures. If our caretakers keep us constantly warm and watered, we never receive the signal to rest and recharge. Without this crucial dormant phase, we are not prepared for a new season of vigorous growth and flowering. You must allow our foliage to die back and give us a dry, cool rest for several months.
The soil is our only source of nutrients. While we appreciate nourishment, the wrong type can be detrimental. A fertilizer with too much nitrogen will encourage us to produce an abundance of lush, green leaves at the expense of flowers. Nitrogen promotes vegetative growth. We require a fertilizer higher in phosphorus (the middle number on the bottle) to promote strong root development and, most importantly, flower formation. An imbalance tells our system to prioritize leaves over blooms.
Our relationship with our container is complex. If our pot is excessively large, we will direct all our energy into expanding our root system to fill the vast space. This root growth takes precedence over flowering. Conversely, if we are severely pot-bound, our roots become tangled and stressed, unable to effectively uptake the water and nutrients we need to support any function, let alone the energy-intensive process of blooming. We prefer to be slightly root-bound but not excessively so.
If we are a young plant grown from a tuber division or seed, we may simply not be mature enough to flower. Our biological focus is on establishing a strong root system and photosynthetic foundation first. Furthermore, if we were recently divided, the act of being separated is a significant shock. Our energy must be directed into healing our wounds and re-establishing ourselves, which delays our flowering cycle for a season while we recover.
Our hydration needs are precise. During our active growth phase, we enjoy consistently moist soil. However, "moist" does not mean waterlogged. Soggy, oxygen-deprived soil causes our roots to rot, crippling our entire system and preventing nutrient uptake. Underwatering causes immense stress, forcing us into survival mode where flowering is an impossible luxury. Consistent, appropriate moisture is key to our performance.
