Foliar nematodes can also be a problem. Buy new plants in late summer or fall so you can check for infestation. Do not purchase plants that show browning in between leaf veins. Hosta anthracnose can cause large whitish spots with brown edges to form on leaves and stalks. Remove the damaged leaves.
Some cultivars are sun-tolerant, but all do best if they receive shade in the afternoon.
Hostas prefer well-drained soil with plenty of organic matter. Hostas need plenty of moisture during the growing season to support the growth of their large, soft leaves. They will need an inch or more of water per week if not supplied by rains. If the weather is very hot or the plants are in sun or subject to root competition from trees and shrubs, they will need more water. Avoid excessive fertilizer rates.