I have two hostas, one is a medium shade of green, the other is called "watermelon" with dark green on the outside of the leaves and a little lighter on the inside. The "watermelon" hosta is starting to look like the ends of the leaves are burned. Am I giving them too much sunlight (about 6 hours of morning light)? Could this be leaf rot? Any solutions?
Hostas are variable in how much sun they can take. Sun + heat + dry soil is very problematic. Some will exhibit leaf scorch with 6 hours of sun. "Morning sun", to me, means up to 11am and that's it. There is one other possibility, hosta virus X or HVX. I've included a link that gives description and pictures of this disease. I don't believe you are describing HVX but check it out. http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/viruses/hosta-virus-x.aspx