Although hostas (Hosta spp.) are typically reliable and easy-to-care-for plants throughout the garden in U.S. Department of Agriculture plant hardiness zones 3 through 9, they are not immune to problems. If you want to prevent holes in their foliage and possible defoliation, keep a few things in mind when growing and caring for these plants. Although slugs are the likely culprits when it comes to chewed foliage, they are not a hosta's only hole-causing nemesis.
Monitor the ground around the hostas and on the leaves to look for slime trails. If you spot some, the slugs who left them are likely to chew holes through the foliage, so choose one of several ways to keep slugs under control. For example, place wooden boards around the hosta garden, and in the morning, look underneath for slugs. Wear gloves, toss the slugs into a bucket of soapy water, place the boards back, and repeat the next morning. You can also dig a hole and place a soup can in it so that the rim is at ground level. Fill the can with 2 inches of beer, and slugs located within a few feet will fall in overnight. Replenish the beer every day until few to no slugs are trapped. For the best control, set several traps around the entire garden.
Check the weather report daily, because hail and frost can cause holes in hosta leaves. Grow hostas in a protected area, such as under a roof overhang. Although cold weather eventually causes the hostas to die back to the ground for the winter, you can protect hostas in the event of a late spring frost or an early fall frost when they should still be growing and thriving. Cover plants with baskets, boxes or buckets, or set up stakes and drape a sheet to the ground. Do not touch the leaves with such covers. Remove the protection in the morning, and repeat in the evening, if necessary.
Grow hostas away from trees with lots of falling matter, such as maple seeds and walnuts. Hosta foliage is easily susceptible to damage, and holes could result.
Remove debris under and around the hostas to discourage other insects, such as earwigs and cutworms, that can chew holes in hosta leaves. Water the plants in the morning, so that the top of the soil can dry out before nightfall. Consistently wet conditions often attract insects.
Things You Will Need
- Wooden boards
- Soapy water
- Baskets, boxes or buckets
- University of Illinois Extension: Hosta and Holes in Leaves
- Melinda Myers: Holes in Hosta Leaves
- Missouri Botanical Garden: Hosta Problems
- University of California Agriculture and Natural Resources: Snails and Slugs
- Fine Gardening: Genus Hosta (Plantain Lily)
- University of Minnesota Extension: Hosta -- Holes in Leaves or Leaves Chewed Off
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