From our rooted perspective, we experience the world through our leaves, stems, and flowers. The appearance of holes in our hollyhock leaves is not merely an aesthetic issue for us; it is a direct assault on our very means of survival. These holes represent a breach in our primary factories—the leaves that harness the sun's energy to create the food that sustains our growth and glorious blooms.
The most frequent cause of this damage is the ravenous feeding of the hollyhock sawfly larva (*Neoptilia malvacearum*). To you, they may look like small, sluggish caterpillars, but to our leaves, they are relentless consuming machines. They begin their feast on the undersides of our lower, older leaves, skeletonizing the tissue and leaving behind a lace-like pattern of veins. As they grow and multiply, they move upward, consuming larger sections and creating the characteristic ragged holes. This systematic defoliation severely weakens us, depleting our energy reserves and leaving us vulnerable to other stressors.
While the sawfly is our most common tormentor, other insects also find our foliage irresistible. Japanese beetles arrive in groups, and their feeding is far less delicate than the sawfly's; they chew large, irregular holes between the leaf veins, often completely stripping a leaf in a short time. Various caterpillars, including those of the painted lady butterfly, also munch on our leaves. While we have a symbiotic relationship with butterflies, an overabundance of their juvenile forms can still cause significant harm to an individual plant.
We are not passive victims in this struggle. Our first line of defense is physical. Our leaves are covered in rough, hairy textures designed to deter some smaller pests from finding a comfortable foothold to feed or lay eggs. Furthermore, we possess a complex internal chemistry. When our leaf cells are ruptured by chewing mouthparts, we often release bitter-tasting or mildly toxic compounds in an attempt to make ourselves less palatable. However, pests like the sawfly have evolved a specific tolerance to these particular chemical defenses, making them uniquely suited to target us.
The holes themselves are only part of the problem. Each wound is an open doorway for fungal spores and bacterial pathogens to enter our system. Diseases like hollyhock rust (*Puccinia malvacearum*) find it much easier to establish themselves on a plant already weakened by insect damage. This combination of insect assault and subsequent disease can quickly overwhelm our natural defenses, leading to a rapid decline in health, stunted growth, and a severe reduction in flowering.
Our ability to withstand these attacks is greatly influenced by the care we receive. When planted in optimal conditions—with ample sunlight, well-draining soil, and adequate spacing for air circulation—we are stronger and more resilient. A stressed hollyhock, perhaps from drought, poor soil, or overcrowding, produces fewer defensive compounds and is far more susceptible to a pest outbreak. The vigilance of our gardeners in regularly inspecting the undersides of our leaves for the first signs of sawfly larvae is our greatest ally. Early intervention can prevent a small infestation from becoming a devastating one.
