Q.Why are some of my hostas so small
Why are some of my hostas so small; they seem stunted? In a bed of 8-10 hostas, which were once all the same big size, now 3-4 of them are small and one actually died last year and I had to replace it. No sign of bugs or chewing of the leaves, just small plants. They are mostly shaded. Maybe an hour or so of sun.
Hostas are quite hardy once they are established. Is your soil well draining? Plants need to be moist but not wet. Crown rot could be the culprit on the hosta you lost.
Here is an excellent article with an overview of growing requirements.
https://www.gardeningknowhow.com/ornamental/foliage/hosta/growing-hosta-plants.htm