I recently purchased my mom a Victory (species) Hosta (so it was free for her), and it got me to wondering if I can propagate a Hosta by a root cutting like rhubarb, and comfrey for when it comes time to dig the plant in the spring (to have a few more).
A standard way to multiply a mature hosta is by "division" just like most herbaceous perennials. Dig it up, chop up the root ball into several pieces with a spade, and replant them as separate plants.
Cutting the root ball with a spade or a knife will cause less damage than trying to pull it apart "carefully."
In practice "mature" means the plant has grown so big that a dead region with no growing stems is forming in the middle.
Trying to do this with a small young plant would be more risky.
The old leaves may die when you do this (in fact some people suggest cutting off all the old leaves when you split the root ball) but new leaves should soon grow from the roots.