Greetings, caretaker. We, the hollyhocks standing tall in your garden, are resilient beings, but sometimes we fall ill. While rust is the ailment most often discussed, other afflictions can weaken our stems, blemish our leaves, and prevent us from producing our magnificent flower spires. From our perspective, here is a detailed account of these other common challenges.
From deep beneath the soil, a silent threat can emerge. When our feet are constantly wet, the oxygen we need for our roots is stolen away. This waterlogged environment invites a water mold called *Phytophthora*. It is not a true fungus, but its effect is devastating. It attacks our root system, the very foundation of our being. We cannot absorb water or nutrients effectively. Above ground, you will see our lower leaves yellowing and wilting, even when the soil feels damp. Our growth becomes stunted, and our entire structure may collapse. The key to solving this is not a cure, but prevention. You must ensure we are planted in well-draining soil. Avoid overwatering, and if an area is consistently soggy, consider relocating us to a raised bed where our roots can breathe freely.
This disease, caused by fungi like *Colletotrichum*, feels like a sudden, burning plague upon our leaves. It begins as small, water-soaked spots that rapidly expand into large, tan or brown irregular patches. Often, these spots have a dark, purplish-brown border, making it look as though our leaves have been scorched by fire. In severe cases, the spots merge, causing entire leaves to wither, curl, and die prematurely. This robs us of our ability to photosynthesize and weakens us for the flowering season. To help us, you must act with cleanliness. Remove and destroy all infected leaf debris in the fall, as the fungus overwinters there. Improve air circulation around us by avoiding overcrowding. If necessary, a fungicide containing chlorothalonil or neem oil can be applied as a protective measure when new growth emerges in spring.
This is perhaps the most common cosmetic issue we face, especially later in the growing season. A fungus named *Podosphaera* spreads a tell-tale white or gray, powdery coating on our upper leaf surfaces. While it rarely kills us outright, it is a significant stressor. This coating interferes with photosynthesis, causing our leaves to yellow and distort. It makes us look unsightly and can reduce the vigor of our blooms. We are most vulnerable in conditions of high humidity combined with warm days and cool nights, especially when air circulation is poor. To combat this, please water us at the base in the morning so our leaves have time to dry. Pruning nearby plants to increase airflow is a great help. Organic solutions like a weekly spray of milk diluted with water (1 part milk to 2 parts water) or a baking soda solution can create an inhospitable surface for the fungus.
These are two of the most frightening diseases from our perspective, as they attack our vascular system—the very plumbing that moves water from our roots to our leaves. Southern Blight (*Sclerotium rolfsii*) appears suddenly in hot weather. You will see a white, mat-like fungus at the base of our stem, along with small, mustard-seed-sized sclerotia. We will wilt and collapse rapidly. Verticillium Wilt is more insidious. It causes a gradual yellowing and wilting of our older, lower leaves, often affecting one side of the plant more than the other. Inside our stems, the water-conducting tissues become darkened. There is no cure for these soil-borne diseases. The best action is to remove and destroy us entirely (do not compost). You must avoid replanting hollyhocks or other susceptible plants like tomatoes or roses in that same spot for several years.
