Leaf Browning, Scorch, on Hostas and Other Shade Plants
Brown leaf edges are common on hostas and other shade lovers when the temperatures rise or the sun is too intense.
Brown leaf edges, known as scorch, occur when the plant loses more water than is available or faster than the plant is able to absorb. Reduce the risk of this problem by growing shade lovers like hostas in shady areas free of hot mid-day and afternoon sun.
Add organic matter to the soil to improve the water-holding ability of fast draining sandy soils. Water the plants thoroughly and often enough to keep the soil slightly moist.
Mulch the soil with shredded leaves, evergreen needles or other organic matter to keep the soil cool and evenly moist. Yes, I know, this also creates the perfect environment for slugs. If a slug problem develops, capture these slimy pests with beer in a shallow can.
A bit more information: If slugs are a problem considering planting more slug-resistant hostas. These tend to have thicker leaves like the 2014 Hosta of the Year, Abiqua Drinking Gourd.