The Anthurium, commonly known as the Flamingo Flower, is celebrated for its glossy, dark-green foliage and vibrant, heart-shaped spathes. Owners often encounter leaves turning brown, which is a symptom indicating environmental or cultural stress. Understanding the specific nature and location of the browning is the first step toward diagnosing the underlying issue. This analysis identifies the primary causes of foliage damage to help restore the plant’s health.
Incorrect Moisture Levels and Nutrient Buildup
Inconsistent watering practices are the most frequent cause of brown Anthurium leaves, affecting the root system and nutrient absorption. Overwatering is characterized by dark, soft, or mushy brown patches, often with surrounding yellow tissue. Saturated soil starves the roots of oxygen, leading to anaerobic conditions and fungal root rot. Damaged roots, which may appear black and slimy, cannot transport water efficiently, causing foliage damage.
Conversely, underwatering indicates tissue desiccation. Lack of moisture causes leaf cells to collapse, resulting in crispy, dry brown edges or tips. The leaves may lose their sheen and droop before browning. Water the plant thoroughly only when the top inch of soil feels dry to the touch.
Brown leaf margins and tips can also signal fertilizer burn from a buildup of mineral salts. When applied too frequently or concentrated, these salts draw water out of the roots, causing osmotic stress and dehydration. This chemical overload results in dry, brittle brown borders, sometimes with a white crust of crystallized salts on the soil surface. To correct this, flush the soil thoroughly with a large volume of clean water to leach the excess salts out of the potting medium.
Light, Temperature, and Humidity Stress
Environmental atmospheric factors also cause Anthurium leaves to brown. Direct, intense sunlight leads to leaf scorch or sunburn. This damage appears as bleached, dry, and irregular brown patches centralized where light intensity was highest. Excessive solar radiation destroys the plant’s chlorophyll, resulting in necrotic brown spots that feel crispy. Relocate the plant to a spot providing bright, indirect light, such as behind a sheer curtain, to prevent further tissue destruction.
Temperature fluctuations and extremes can also result in rapid browning of the foliage. Exposure to cold drafts or uninsulated windows causes cold damage. This stress often results in dark, mushy, or blackened-brown areas on the leaves, giving them a water-soaked appearance. Anthuriums thrive in stable temperatures between 65°F and 80°F, making them sensitive to sudden drops. Heat stress can also cause browning, sometimes appearing similar to sunburn or dehydration if the air is too hot and dry.
These tropical plants require high atmospheric moisture, with optimal humidity levels ranging from 60–80%. Low humidity environments, often created by indoor heating or air conditioning, cause excessive transpiration. The lack of moisture results in dry, brittle brown tips and edges as the plant struggles to retain water. Placing the pot on a pebble tray filled with water or using a room humidifier helps restore the necessary moisture balance and prevents desiccation.
Insect Infestation and Pathogen Activity
Biological threats cause Anthurium leaf browning and require intervention. Common houseplant pests like spider mites, scale, and mealybugs feed by piercing the leaf tissue and sucking out the internal sap. This feeding causes localized damage appearing as tiny yellow or brown stippling spots, which merge into larger necrotic areas. Pests are often identified by fine webbing (spider mites) or sticky residues called honeydew (scale and mealybugs), typically found on the undersides of the leaves.
Pathogens, including fungal and bacterial infections, also cause leaf browning by creating distinct spots. Fungal diseases like Anthracnose or bacterial blight manifest as small, circular, dark brown spots, sometimes surrounded by a yellow halo. These infections thrive in overly wet conditions and poor air circulation. Root rot, a fungal issue caused by overwatering, results in the mushy brown symptoms discussed previously. Water the plant at the soil level and isolate the affected plant. Treatment involves prompt removal of infected leaves using sterilized tools and applying an appropriate fungicide or bactericide to stop the spread and protect new growth.