Question
Can i split ornamental grasses - and when is the best time to do so

Answer
Hi Peter,
Thanx for your question.  You most certainly may split/separate ornamental grasses.  The best time to do it is in the fall as the plant begins to go into dormancy but you can really do it at any time.  Preferably in the evening when the sun is beating down on the plant.  Be sure to heavily hydrate the plant upon replanting and side dress with well-composted manure.  Continue to hydrate the plant regularly (at least once or twice a week) if no regular rain.  I hope this helps.
Tom