Holes In Your Hostas? Slugs Are Probably the Culprit
You've got several options for keeping these slimy critters from munching on your plants.
As reliable garden workhorses that come back year after year, hostas fill shady spaces with their lush foliage that come in all sorts of sizes, textures, and hues of green. Many varieties also have pretty flowers that pollinators appreciate. But one morning you may walk into your garden and find holes riddling the beautiful leaves of your otherwise thriving plants. Unless there was a hailstorm the day before, the top three suspects for making those holes are slugs, slugs, and slugs. But don’t despair! There are several ways you can stop slugs in their slimy tracks and keep them away from your hostas all summer long.
Garden Pests That Eat Hostas
Before you declare war on slugs, be sure they’re what's making holes in your hostas. Besides hail, cutworms could also be the culprits; their signature is chewing the soft parts of the leaves and avoiding the veins. Slugs will munch anywhere on the leaves, right through the veins. Deer and rabbits will eat hostas, too, but they don't leave holes behind. Instead, you'll likely see just bare stems with maybe a ragged piece of leaf left behind.
How to Get Rid of Slugs
Slugs like damp places where they can slide around easily. Rake away any dead leaves near your hostas and add some rough mulch, like bark, around your plants. You can also sprinkle diatomaceous earth around your hostas. Slugs don't like the feeling of the tiny but sharp crystals in this nontoxic powder. Ground up eggshells can have the same effect. If you only have a small area to protect, you could try circling it with copper tape at ground level. The slime on the slug’s foot creates a chemical reaction with copper that gives it an electrical shock.
If you aren't too squeamish, you can go hunting for slugs at night when they are most active. Use a flashlight so the beam will glint off their slimy trails, which you can follow to find the slugs making the tracks. Then either drown them in a container of soapy water or feed them to any backyard chickens you know (chickens love slugs).
You can also set up a slug hotel in the garden by leaving out a smooth piece of cardboard or small wooden board on the ground in a damp, shady spot. Give the slugs a day or two to check in before turning over the cardboard or board and evicting your unwelcome guests.
And then there’s the poison route, but you'll need to make sure you don’t use anything that might also harm birds, pets, and children. Happily, iron oxide is toxic only to slugs and snails. Scatter a slug bait with iron oxide, like Sluggo, around each hosta. Check back every two weeks, and after big rains, and replace the bait if it’s gone.
It may take several of these tactics to finally stop slugs from chewing on your hostas. You'll know that your efforts are working when you start seeing new, hole-free leaves growing and replacing the damaged ones.