From my perspective as an Adenium, light is my primary source of energy. My leaves are solar panels, converting sunlight into the sugars I need to grow and sustain myself. When light levels drop, such as during shorter winter days or if I am moved to a shadier location, I must make a difficult calculation. Maintaining a full canopy of leaves requires more energy than those leaves can produce in low light. This creates an energy deficit. To ensure my long-term survival, my systemic response is to strategically abandon what I cannot support. I will jettison leaves to conserve my core energy reserves, stored in my thick caudex, until conditions improve and I can efficiently photosynthesize again.
My relationship with water is complex. My succulent stem stores water, making me highly susceptible to overwatering. Saturated soil fills the air pockets around my roots, effectively drowning them. Without oxygen, my roots begin to rot and die, severing my ability to uptake water and nutrients at all. In this scenario, my leaves wilt and drop because they are literally dying of thirst, despite the wet conditions. Conversely, while I am drought-tolerant, extreme underwatering for a prolonged period will also cause me stress. To prevent excessive water loss through transpiration (the plant version of sweating), I will shed leaves to reduce my surface area and conserve the precious water held in my caudex.
I am a child of the sun and thrive in warmth. A significant drop in temperature, especially when coupled with reduced light, signals to my internal biology that it is time to enter a dormant period. This is not a sign of distress but a natural survival strategy. Dormancy is a state of suspended animation where I drastically slow my metabolic processes to conserve energy. As part of this programmed shutdown, I will systematically withdraw nutrients from my leaves and shed them. This allows me to redirect all my energy to my core—the stem and roots—to safely wait out the unfavorable conditions until warmth returns and signals it is time for new growth.
I am highly attuned to my immediate environment. Any abrupt change is interpreted as a potential threat, triggering a stress response. This includes being repotted, which disturbs my root system, or being abruptly moved from a sheltered location to full, blazing sun (or vice versa). Even a drastic change in ambient temperature from a move can cause shock. This sudden shift forces me to expend a tremendous amount of energy to acclimate to the new conditions. Leaf drop is a common reaction to this stress as I divert resources away from maintaining foliage and toward stabilizing my systems and re-establishing root-to-soil contact.
While not a physiological process like the others, an attack by pests such as spider mites, scale, or mealybugs is a direct assault on my vitality. These pests pierce my leaves and stems to feed on my sap, which is rich in the sugars and nutrients I have worked hard to produce. A severe infestation acts as a massive drain on my resources. The damage they cause disrupts the vital flow of nutrients and water within me. Weakened and under attack, the affected leaves often yellow and drop as I am effectively robbed of the means to sustain them, forcing me to sacrifice them to protect the whole organism.
