From my perspective as a Nerine bowdenii, the most common reason for my leaves turning yellow is simply the natural cycle of my life. I am a geophyte, meaning I grow from a bulb, and my life is dictated by distinct seasonal rhythms. My leaves emerge in the autumn, persist through the winter, and work tirelessly through the spring to photosynthesize and store energy in my bulb. As summer approaches and temperatures rise, this is my signal to enter a period of dormancy. My leaves will naturally begin to yellow, wither, and die back. This is not a cause for alarm but a necessary rest period. Conserving my energy within the bulb allows me to produce my beautiful pink flowers on leafless stalks in the late summer or autumn, right before a new cycle of leaf growth begins.
Your watering habits directly impact my root system and overall health. During my active growth phase in the cooler months, I appreciate consistent moisture. However, my bulb is highly susceptible to rot. If you water me too frequently, especially during my summer dormancy when I am not actively growing, the soil becomes waterlogged. This suffocates my roots, preventing them from absorbing oxygen and nutrients. From my point of view, it's a drowning sensation. The first sign of this distress is the yellowing and softening of my leaves as the rot begins to travel upward from the compromised roots. Conversely, while I am drought-tolerant, extreme and prolonged dryness during my growth period can also cause my leaves to yellow and crisp up as I struggle to sustain myself.
The soil I am planted in is my entire world; it is my sole source of sustenance. If the soil is depleted of essential nutrients, I cannot perform basic functions. A lack of key nutrients, particularly nitrogen which is vital for chlorophyll production and green, leafy growth, will manifest as a general yellowing (chlorosis) of my foliage. From down here in the ground, it feels like a constant state of hunger and fatigue. My leaves lose their vibrant green vigor because I simply cannot manufacture the green pigment without the necessary building blocks. While I am not a heavy feeder, a complete lack of nutrients in poor, exhausted soil will inevitably lead to a decline in my health, shown through my yellowing leaves.
As a plant, sunlight is my food source. The process of photosynthesis, which occurs in my leaves, converts light energy into chemical energy to fuel all my processes. I thrive in a location with full sun. If I am planted in too much shade, the amount of energy I can produce is drastically reduced. From my perspective, it is like trying to run on an empty stomach. To conserve my limited energy reserves, I may begin to sacrifice older leaves, allowing them to yellow and die back. This ensures that what little energy I can produce is directed toward sustaining my most crucial parts—the bulb and any new growth—in the hope that conditions will improve.
Although less common, an infestation of sap-sucking pests like aphids or bulb mites can cause my leaves to yellow. These pests pierce my tissues and feed on my nutrient-rich sap. This is not only a direct drain on my resources but also an open pathway for disease. The physical damage and the stress of the attack disrupt the normal flow of water and nutrients within my leaves, leading to discoloration, spotting, and yellowing. From my point of view, it is a constant assault that weakens me, forcing my energy to be diverted from growth to defense and repair.
