The Peace Lily, Spathiphyllum, is a popular houseplant recognized for its glossy, dark green foliage and distinctive white, sail-like blooms. What most people call the flower is actually a modified leaf structure called a spathe, which wraps around the central flower spike, or spadix. When these pristine white spathes turn green, it is usually a common response to either the plant’s natural biological processes or specific environmental conditions.
The Natural Maturation Process of the Peace Lily Spathe
The greening of a Peace Lily’s spathe is often simply a sign of its natural life cycle nearing completion. The spathe’s primary function is to protect the tiny, true flowers located on the central spadix and to attract pollinators in its native tropical environment. As the spathe ages, usually after two to three weeks, the plant begins to reabsorb nutrients and repurpose the structure.
This process involves the spathe initiating the production of chlorophyll, the pigment responsible for the green color in leaves. The spathe, being a leaf-like bract, essentially converts back to a photosynthetic organ, allowing the plant to recover energy from the bloom.
Once the spathe has fully turned green, it will not revert to its original white color, signifying that the bloom has finished its reproductive purpose. The green spathe will eventually dry out and turn brown, indicating it is time for removal.
Excessive Light Exposure as the Primary Cause
While maturation is one reason for greening, an accelerated color change across multiple spathes often points to light intensity issues. Peace Lilies are native to the shaded forest floor, thriving in filtered or low-light conditions. When the plant receives excessive light, the spathe reacts by stimulating the production of chlorophyll within its tissue.
Since the spathe is fundamentally a leaf, the plant perceives the abundance of light as an opportunity to increase its overall photosynthetic capacity. This biological mechanism results in the spathe turning green prematurely to contribute to the plant’s food production. The intensity of the light, rather than the duration, is the most common trigger for this reaction.
To correct this issue, the Peace Lily should be immediately relocated to a less exposed position. Optimal placement involves medium, indirect light, such as a few feet away from a south- or west-facing window, or near an east-facing window where morning light is gentler. The light should be bright enough to support healthy leaf growth but diffused enough to prevent the spathes from being overstimulated. Adjusting the plant’s position effectively reverses the environmental stressor and encourages future blooms to remain white for a longer period.
Nutritional Imbalances and Maintenance Solutions
The composition and amount of fertilizer applied to the soil can also influence the color of the Peace Lily’s spathes. Over-fertilizing the plant, particularly with formulas high in nitrogen, can lead to a nutritional imbalance that promotes lush vegetative growth. Nitrogen is a primary component of chlorophyll, and an excess of this nutrient can stimulate the plant to produce more green tissue, including in the spathes.
Peace Lilies require a minimal feeding schedule, often thriving with a balanced, water-soluble houseplant fertilizer diluted to half-strength, applied every six to eight weeks during the active growing season. If a Peace Lily is consistently overfed, it will often prioritize the production of green leaves and green spathes over the desired white blooms. Reducing the fertilizer concentration and frequency is the appropriate management solution for this issue.
When a spathe has fully turned green, or once it begins to brown, physical intervention through pruning is recommended. This maintenance practice, known as deadheading, is performed by following the flower stalk down to the base of the plant where it emerges from the foliage. Using clean, sharp shears, the entire stalk should be cut off as close to the soil line as possible. Removing the spent bloom redirects the plant’s energy away from maintaining the deteriorating tissue and encourages the plant to produce new, white flower stalks.