From our perspective down here in the soil, the most common culprits for those ragged, hole-ridden leaves are slugs and snails. We find them particularly vexing. They are primarily nocturnal feeders, using their rasping mouthparts (called a radula) to scrape away at our tender leaf tissue. They prefer the cool, damp conditions of night and are especially active after rain or watering. You will rarely see them at their work, but the evidence they leave is unmistakable: irregular holes between our leaf veins and a characteristic slimy, silvery trail glistening on our foliage or the soil nearby. They are the bane of our existence, as they not only disfigure us but also weaken our ability to photosynthesize effectively.
While slugs are the usual offenders, we are sometimes a buffet for other insects. Certain beetle species, like the black vine weevil or the Japanese beetle, can also be to blame. Adult beetles chew distinct, more rounded holes or notch our leaf margins. Their larvae, which live in the soil, pose a different threat by feeding on our precious root systems, which is even more distressing as it directly impacts our ability to uptake water and nutrients. Occasionally, cutworms or grasshoppers might also decide to take a bite, leaving behind their own unique damage patterns.
Not all holes are from a pest's mouth. Sometimes, the damage is accidental. Hailstorms can brutally puncture and shred our broad leaves in a matter of minutes. Misguided gardening tools, like a string trimmer or a careless footstep, can cause similar traumatic injuries. It is important to correctly diagnose the cause, as the remedy for a hail wound is very different from the remedy for a slug infestation. We cannot heal these damaged tissues, but we can often regrow new leaves if our crown and roots remain healthy.
To stop the assault, you must first identify the attacker. For slugs and snails, the most effective and plant-friendly method is to handpick them at night with a flashlight and drop them into soapy water. Creating barriers is also highly effective. You can surround us with a ring of diatomaceous earth (which must be reapplied after rain), crushed eggshells, or copper tape, which gives them a slight unpleasant shock. Providing a hospitable environment for their natural predators, such as ground beetles, birds, and toads, is a wonderful long-term strategy. For severe infestations, iron phosphate-based baits are considered safe for use around pets and wildlife while being deadly to slugs.
Our best defense is your good gardening practices. Keeping the garden area clean of leaf litter and debris removes the daytime hiding places for slugs. Watering us in the morning, rather than the evening, allows our foliage to dry before nightfall, making us a less appealing target for moisture-loving pests. Ensuring we have adequate spacing improves air circulation, which also helps keep our leaves drier. A strong, well-fed hosta is more resilient and can better withstand and outgrow periodic pest damage. Please provide us with rich, well-draining soil and appropriate shade, and we will reward you with our beautiful foliage.
