From our perspective beneath the soil, the difference between too much and too little water is a matter of life and death. When overwatered, the soil becomes a waterlogged prison. The vital air pockets that normally hold oxygen are flooded, and our roots begin to suffocate and rot. This rot, often starting as a soft, brown mush, prevents us from absorbing any water or nutrients at all, ironically leaving us desperately thirsty despite the soggy conditions. Conversely, underwatering creates a desert-like environment. The soil pulls away from the container's edges, and our delicate root hairs, the primary organs for water uptake, desiccate and die. Without these microscopic structures, we cannot drink even when water is finally provided, leading to a systemic shutdown.
The condition of our stems tells a clear story of water distress. Under the constant strain of overwatering, our tissues become unnaturally soft, weak, and floppy. The cellular structure is compromised, making us unable to support the weight of our own vibrant bracts and leaves. We may develop a foul, musty odor at the base, a sure sign of advanced stem rot. In stark contrast, the stems of an underwatered bougainvillea become hard, woody, and exceptionally brittle. We conserve every last drop of moisture, sacrificing flexibility. A gentle bend might cause us to snap audibly, a direct result of having no water to hydrate our cell walls and maintain pliability.
Our leaves are the most honest communicators of our discomfort. Overwatering forces us to exhibit a very specific kind of distress: generalized chlorosis. This means our older leaves turn a uniform, pale yellow or even light green before dropping off. They often feel soft and limp to the touch. Simultaneously, new growth may emerge but remain small and stunted. Underwatering, however, prompts a dramatic and conservative response. Our leaves wilt severely, becoming dry, crispy, and brittle. They will curl inward at the edges to reduce surface area and minimize water loss. The color shifts to a dull, dusty green or brown before we are forced to sacrifice them entirely in a desperate attempt to survive. The leaf drop from underwatering is typically rapid and severe.
Our ultimate goal is to produce stunning displays of colorful bracts to attract pollinators. Both extremes of water management prevent this spectacular show. Overwatering encourages us to focus all our energy on weak, vegetative growth at the expense of flowering. You will see an abundance of new, often pale green shoots with large gaps between leaves (etiolation), but few to no flower buds. The stress of root rot completely halts our reproductive process. Underwatering is just as effective at stopping the show. The immense stress of drought causes us to abort flower buds prematurely or to simply not produce any at all. We enter pure survival mode, and reproduction is a luxury we cannot afford when our very hydraulic system is on the verge of collapse.
