Greetings, caretaker. We, the lobelias, bring vibrant spikes of blue, purple, and white to your gardens and containers. To thrive and bloom profusely, we require your vigilance against two of our most common adversaries: Powdery Mildew and Root Rot. From our perspective, here is what you need to know.
This fungal disease appears as a ghostly, white, powdery film on our leaves and stems. It is most prevalent in conditions where our foliage remains damp through the night but the days are warm and dry. Poor air circulation around us, often caused by being planted too closely together, creates the perfect environment for this pathogen to settle. From our point of view, this coating is not just unsightly; it is a direct attack. It blocks the sunlight from our leaf surfaces, hindering our ability to photosynthesize and create the energy we need to grow and flower. Severe infections can cause our leaves to curl, twist, and turn yellow before eventually withering and dying, severely weakening us.
Your intervention is crucial. First, please ensure we are planted with enough space between us for air to flow freely, which helps our leaves dry quickly after watering or dew. When you water us, aim the water at our soil base, not over our heads, to keep our foliage as dry as possible. If the white powder does appear, you can create a simple mixture of one tablespoon of baking soda, half a teaspoon of liquid soap, and one gallon of water. Spraying this on our affected areas can alter the pH on our leaf surfaces, making it inhospitable for the fungus. For more persistent cases, we may need a treatment of a registered horticultural oil or neem oil, which will smother the fungal spores. In all cases, promptly remove and dispose of any severely infected leaves to prevent the spread.
While Powdery Mildew attacks us from above, Root Rot attacks from below, and it is often fatal. This condition is caused by various soil-borne fungi, such as *Pythium* or *Phytophthora*, that thrive in waterlogged, poorly draining soil. When our roots are constantly saturated, they cannot access the oxygen they need to function and begin to suffocate and die. From our perspective, this is a slow and devastating collapse. The decaying roots can no longer take up water or nutrients, no matter how moist the soil is. You will see the signs above ground: we will wilt dramatically, our growth will be stunted, our lower leaves may turn yellow, and our stems may become soft and dark at the base.
Prevention is the absolute best medicine for Root Rot. Please plant us in well-draining soil. If we are in containers, ensure there are adequate drainage holes and never let us sit in a saucer full of water. You must check the soil moisture before watering; we prefer it to be slightly moist, not sopping wet. If you suspect Root Rot, you must act quickly. Gently lift us from the soil and inspect our root system. Healthy roots are firm and white or light tan. Rotten roots are mushy, dark brown or black, and may have a foul odor. Using sterile shears, carefully trim away all the affected roots. Then, replant us in fresh, well-draining soil, and be very cautious with water until we show signs of new growth.
