Clematis heracleifolia division time.
I was given a small C.heracleifolia with lovely blue flowers last year, and this year it has grown to a very large size. I would like to divide it but am unable to find information as to the best time to do this, either spring or autumn. It is still blooming. I am in Canada Zone 5B. Any advice is appreciated. I have also posted this in the Clematis forum, but any advice from Canadian gardeners is appreciated.
Thank you all in advance