In the middle of the growing season it is not advisable to divide a Canna. I would wait until the fall if you are digging it up for next year or next spring before the new growth starts.

The sprouts you are seeing are all part of the original rhizome. Cannas expand during there growing season they do not send runners out like EE's. As for you Pine tree question I do not see why they would not do well near Pine trees as long as they are not under them. Cannas like full sun and lots of water and fertilizer.

Thanks for the response.

So it will be okay to split them from the original rhizome in the fall?

Do you dig your Cannas in the fall and store them?

Yes, if you are in a freeze zone like NY. I am in the south so mine stay in the ground all year. When I want to devide them I dig them up and put them in water and devide them that way. You can see the rhizomes better when all the dirt is off them. Put them in a box with air holes and store in a cool place for winter.
Sky~~

I actually divide mine in the Spring. Mine overwinter in the raised beds I have. I put approx. 3 inches of mulch over them after the first frost and they have done fine for the last 3 years.