Hello, fellow photosynthetic organism. I sense your concern through the soil, a vibration of worry as you inspect my foliage. From my perspective, here are the primary reasons my leaves may be turning from a vibrant green to a troubling brown.
My roots are my mouth. When the top few inches of soil become dry and dusty, I cannot drink. This causes drought stress, where my leaves, especially at the edges and tips, will crisp and turn brown as I essentially begin to wither. Conversely, if my roots are sitting in constantly soggy, waterlogged soil, they begin to suffocate and rot. A rotting root system cannot transport water or nutrients to my leaves, which then brown, yellow, and droop. I need deep, infrequent watering that allows the soil to become moist but not saturated, like a well-wrung sponge.
This is a common assailant in the humid springs of many US gardens. The fungus *Botrytis cinerea* finds me when the air is moist and crowded. It appears as a gray, fuzzy mold on my buds, stems, and leaves. The infected areas quickly turn dark brown or black and become soft and mushy. The disease often starts on decaying plant material left near my base or on spent flower petals stuck to my leaves. It can spread rapidly, causing entire stems to collapse. Good air circulation around my form is my best defense.
This issue, caused by the fungus *Cladosporium paeoniae*, presents as glossy, purple-brown, irregular blotches on my leaves that can coalesce into large brown areas. It is often a sign that my environment is not ideal. While it is a fungal pathogen, it is strongly encouraged by stress, particularly poor nutrition or soil that does not drain well. The problem is that these unsightly blemishes reduce my leaf surface area, impairing my ability to photosynthesize and store energy for next year's growth.
Your intentions are good, but sometimes the help is too much. If a strong, synthetic fertilizer is applied too close to my crown or stems, or if a non-diluted solution touches my leaves, it can draw moisture out of my tissues, causing a rapid browning or scorching. My roots are sensitive, and a high concentration of mineral salts can damage them, leading to brown leaf margins. I prefer gentle, well-composted organic matter worked into the soil around me in the spring.
While I adore the sun for fueling my blooms, my leaves can be sensitive to intense, direct afternoon sunlight, especially when coupled with heat stress and inadequate water. The leaf tissue literally gets burned, resulting in light brown or tan, papery patches, often between the veins or on the areas most exposed to the sun. This is a physical injury from which the leaf cannot recover. A location with morning sun and afternoon shade is often ideal for me.
