More water will make for larger hosta leaves, but you may also want to divide your hosta plants. You can do this in the fall or spring, and the thick roots can be cut up with an axe or power tool as, in most cases, a shovel will not penetrate the centre of the hosta clump. Replant the younger side sections cut from the old plant and discard the old center or heart of the original plant. Dividing up old plants will allow you to amend and improve the soil with compost and organic matter before replanting. You must provide extra water the first summer after dividing your plants as the new roots are established. Fertilize in spring when you see new leaves beginning to sprout. A slow-release plant food like Osmocote will encourage much larger plants as it contains all the micronutrients plus major nutrients that your hosta plants need. Keep growing, Marianne Binetti