Becca welcome to canna gardening. Seems like you got very lucky and inherited a nice canna garden. The plants you describe are probably Musofolia or Omega. The two largest canna variety. I have found that canna, especially those, are not particularly happy with super hot weather. I think when the temps goes above 95f or so, they stop growing and may even get a little distressed. But don't worry about that, just give them water periodically. Every couple of days a good watering should do it. Adjust that as you see fit. As for taking care of them in winter... When the temp drops below freezing the canna leaves will all die. Just cut them to the ground and toss the dead stuff. Under ground they have dense rhyzome bulbs that will regrow in the spring. Since you have so much canna in the ground now, I think it's safe to say that they over-winter well in your location. Lastly, if you really enjoy canna gardening you might look at diversifying your beds a bit. In the spring, dig out some tall plant rhyzomes, before they start to leaf, and find someone who wants to trade short to medium sized canna for your tall canna. Throw some shorter, different color canna, like red canna, in the front of your tall ones and you'll have a small tropical wonderland right there in your yard. Good luck!

Sorry about that. It is the Scot in me ( or as my wife says "the scotch in" me). LOL Wee means small. Cut off the small roots. If they are really huge, the larger ones CAN be cut after cleaning. IF you cut, the wound should be dusted with some sort of bulb and tuber dust ( a fungicide), as well as the rest of the rhizome. Personally, I like to keep the stock together, and divide in the spring, as I mentioned because I can more readily see which are viable sprouts. Store them in a dark, dry place about 55 degrees F. They don't like to be cold or they rot (I found that out the hard way), and they don't like to be hot or they sprout. The rest period is necessary though. By the way, the trimming of the roots, I usually do in the fall as it is easier to clean. However, many folks dig it up, and "park" the clump in the cool, dry spot until spring, and then do the trimming. Either time works well, but trimming in the fall allows for less space being used, if space is at a premium. It is definitely at a premium in my wee house, as I need space for my dahlia, and my 20 + brugmansia trees.

Yes it is leaf spot. The leaf spot spores are in the soil. This disease spreads by water splashing from the soil and the water with the spores splash onto the leaves. Then it spreads to other leaves again from water carrying the spores from leaf to leaf. Pick off the worst leaves--all of them if you can but you don't want to denude a plant. Spread a fairly thick layer of mulch around the plant so the infected soil can't splash. When you water don't wet the plant. Treat with an fungicide for leaf spot. Garlic water and baking soda sprays might help. Be prepared to fight this disease until the soil is sterilized either by solarizing it with plastic or until you have a prolonged hot dry spell. Don't plant suseptible plants in the same place next year

Mine overwinter in the ground. If I had them in pots I'd sink them into the ground. I think how well cannas do in the ground in OK in the winter correlates with how well the soil drains. Mine that were in unimproved clay died in a cold, wet winter although they had tolerated the same temperatures in drier winters. The ones that I have in the band of sandy soil which drains well survive the winters just fine. So do the ones in a raised bed of heavily-improved clay at the entrance to the veggie garden. The in-ground ones get mulched by pecan leaves that fall from the nearby tree, but other than that I don't mulch them in the clayey area.