From my perspective as a plant, the red or purple pigmentation you see is not a part of my natural, everyday wardrobe. It is a sign that I am producing an abundance of pigments called anthocyanins. Think of these as my internal sunscreen. My green chlorophyll is fantastic for capturing light energy, but too much of a good thing, especially intense direct sunlight, can be damaging. The anthocyanin pigments help to absorb excess light energy, particularly in the blue-green spectrum, and dissipate it as heat. This protects my delicate photosynthetic machinery from being overwhelmed and damaged by light stress, a condition known as photo-inhibition. It is a protective response, not unlike you humans developing a tan.
The shift in color is my direct response to environmental stressors that trigger the increased production of these anthocyanins. The most common stressor is light. As a tropical epiphyte (a plant that grows on trees), I am adapted to bright but filtered light beneath the forest canopy. If I am suddenly placed in a location with direct, harsh sunlight—like a south-facing window—the light intensity becomes too great. My system goes into overdrive producing the protective red/purple pigments to shield my tissues. This is the most frequent reason for my change in appearance.
Other environmental factors can also contribute to this stressed state. Inadequate moisture, particularly when combined with bright light, can prompt this reaction. While I am drought-tolerant and prefer to dry out between waterings, extreme or prolonged drought forces me into survival mode, and the reddening can be a sign of this significant stress. Furthermore, a lack of available phosphorus in the soil can manifest as red or purple discoloration. Phosphorus is a vital nutrient for energy transfer within my cells. If it is deficient, my metabolic processes are disrupted, which can inhibit my ability to produce and utilize energy properly, leading to the accumulation of anthocyanins and the subsequent color change.
Temperature plays a significant role as well. I thrive in consistent, moderate temperatures. Exposure to cool temperatures, especially below 50°F (10°C), can slow down my metabolic functions. This slowdown affects how I process sugars and nutrients, which can lead to a buildup of anthocyanins in my tissues, resulting in a reddish-purple hue. While a slight cool period can actually help initiate bud formation for flowering, a sudden cold draft from a window or an outdoor chill can be more stress than I bargained for.
My red or purple leaves are, therefore, a clear visual signal that my growing conditions are not ideal and are causing me stress. It is my way of communicating that an adjustment is needed. To help me return to a healthy green, you should assess my environment. Move me away from direct, harsh sunlight to a spot with bright, indirect light. Ensure you are watering me thoroughly when my soil is dry to the touch, but never letting me sit in water. Consider a fertilizer formulated for cacti and succulents to address any potential nutrient deficiencies, particularly phosphorus. Finally, protect me from cold drafts and extreme temperature swings. With these adjustments, I can reduce my production of protective anthocyanins and return to my lush, green self.
