When is the best time to plant? Do hostas need to be divided?
Spring is the best time to plant, and no, they don't "need" to be divided but it's a great cost-effective way to get more -- and the parent plant will continue to grow.
These articles may help you:
You can plant Hosta at any time you can work the soil, but Spring is the ideal time.
Hosta can be divided if they become crowded or you want to increase the number of plants that you have.
Some varieties never need to be divided.