From my perspective as a rosemary plant, my roots are my entire world. I am a Mediterranean native, built for gritty, rocky, well-drained soils where water never lingers. My roots are designed to seek moisture deeply and infrequently. When I am placed in a pot without proper drainage or in soil that is too moisture-retentive, my roots are essentially suffocating. They require oxygen to function, and constant waterlogging fills the air pockets in the soil, cutting off this vital supply. This creates a stressful, anaerobic environment where my roots begin to break down, becoming soft, brown, and unable to uptake water or nutrients, no matter how much is available.
The main cause of my root rot is overwhelmingly excessive moisture around my root zone. This is often due to overzealous watering. My caretakers must understand that I prefer to be on the drier side; my leaves are adapted to conserve water. Watering on a strict schedule, rather than checking the soil's moisture first, is a common mistake. Furthermore, a pot that lacks adequate drainage holes is like a bathtub for my roots. Even with perfect watering, the water has nowhere to go. Finally, dense, heavy potting soil that retains water like a sponge is a death sentence. I crave a loose, sharply draining mix, often amended with sand, perlite, or small gravel to mimic my native habitat.
I will show clear signs of distress above the soil line, but these are merely symptoms of the crisis happening below. The first sign is often a general wilting or drooping of my stems, which is confusing because it looks like I need water, when in fact, my rotting roots cannot drink. My normally firm, evergreen leaves will become soft, turn yellow, then brown, and eventually fall off. The growth of my new shoots will stall completely. Most tellingly, the base of my main stem may become soft and darkened. A foul, musty odor emanating from the soil is a definitive signal of advanced decay.
If caught early, I can be saved, but it requires immediate and decisive action. I must be gently removed from my pot. The soil needs to be carefully washed from my roots with lukewarm water so the damage can be fully assessed. Using sterilized, sharp scissors or pruners, all soft, mushy, brown, and clearly rotten roots must be cut away. Only firm, white, healthy roots should remain. It is crucial to trim back some of my top growth to compensate for the significant root loss, reducing the demand on the compromised system. I must then be repotted into a clean container with excellent drainage, using entirely fresh, well-draining cactus or succulent potting mix.
After this traumatic process, my care must be meticulous. I should not be watered immediately. Allowing my trimmed roots a day or two to callus over in the dry soil can help prevent reinfection. When watering is resumed, it must be done deeply but only when the top several inches of soil are completely dry. I should be placed in a location with abundant sunlight and good air circulation to help the soil dry appropriately. The most important long-term change is a consistent check of the soil moisture before any watering, ensuring my environment once again matches the dry, arid conditions for which I am evolved.
