Question
Can I thin out my hostas right now in the heat of summer?  They are getting so big

Answer
Hi Joyce,
Thanx for your question.  I would wait until fall to separate my hostas unless it is an absolute necessity.  The heat of summer will put undue stress on them and make it hard for them to recover to be healthy enough to survive winter particularly if you have cold winters.  Hostas are pretty tought and I've moved them in the summer with no ill-effects.  If I could wait, I would.  I hope this helps.
Tom