I'd leave them like that for the winter. In the spring, cut them apart. Cutting them now would hasten their losing moisture. Cannas are really tough, so you shouldn't have to worry.

I plant my Cannas out for the summer, dig them after frost has killed top growth, let the tubers dry in a freeze-free place for a few days. Then brush (not rinse) off the soil, trim back tops, and store in plastic bags of un-moistened peat moss which I keep in cool cellar. Check on them every month or so, cutting back any rot. Wouldn't trim any roots unless they show signs of rot (unlikely, unless stored too damp.)

I find the tubers increase by 3-4 times each summer. If you have above-freezing space for the pots, yours should be OK with good drainage, but may need re-potting as they begin to grow in spring. Not sure how they know when to sprout without light, temp clues, but they do.

Exactly what Solana said :)

But i put mine in peachbaskets full of peat moss & store in basement ( in the DARK) you're supposedly not supposed to let them get light.

You can start growing them insdie in march if you like- to get an early start.

However- beware that if you trim back /divide the tubers- it does affect the blooms! This was the first year that I divided mine and I had a poor show. then I read in a magazine when someone asked why their cannas and dahlias didnt do well that summer- and they said if you divide it- they will do that. so keep it in mind. :) I had the same problem with my cannas and usually each summer I have such a great show. Oh well.. next year ( famous last words)

Just got in from digging mine up actually!

Friend

The smaller blooms are only a temporary setback.

The same thing happens with irises (only they often don't bloom at all the first year after they've been divided.)

If you don't separate crowded cannas/irises/crinums, the competition for nutrients & water will result in smaller plants & smaller, sparser blooms.

If I were storing those cannas in the photo, I'd leave them alone now & separate them in early spring.

Best luck!

Yes, perhaps mine will do better next year. Eventually you do need to dived them- they get too big... but here in the colder climates I read that dividing them does cost you the blooms! But hey- every few years you gotta do it right?
We don't have the mass speading problem you probably have in texas this far north though. I can imagine you woudl have to divide them regularly. I have seen what they do in Virginia at my brotgher's house :)
( I wish i had that problem. ha)
And i did have that problem with my irises. after the first year of no blooms though. the next year was fabulous.. I hope the cannas do the same.
( I do have some irises elsewhere that have been 2 years no with no blooms though... weird.. 3rd year for charm?) ha

Bearded irises are the only ones I know about, & I think the main reason they fail to bloom is deep planting.

The top of the iris rhizome, the part nearest the base of the leaves, should be slightly exposed above ground.

If you can't see part of the rhizome, the iris will be stressed, & it may get iris borers or iris rot.

Also, be careful about what's piled up around it:

Although they need winter protection where you are, some mulches just add to the rot problem.

I'm just too far south to know what mulches are good & what ones are evil, but...

You might post on the Iris Forum;
there're many helpful, knowledgeable people on that forum.

Since I live in the north & have to dig cannas to overwinter indoors anyway, I don't so much divide them as control the size of my clumps. I store them 'whole' overwinter, then, when potting up in the spring to start growing indoors, choose the healthiest, largest rhizomes. Plant 2 or 3 closely in 8" pots (about 4 weeks before last frost for set-out 5-6 weeks later), tease apart a bit when I plant out in well-amended soil, and get great blooms the same year.

Any remaining decent-sized, firm pieces with an eye get potted up separately to use in mixed containers as a foliage accent, and yes, they don't always bloom 1st year.

Except for the year dear SO decided that bag of peat moss in the cellar (in which I'd store the cannas) could spend the winter in unheated shed, I've always had extras to share.

Unless you're dividing primarily to get more plants, my advice is to replant the same or slightly larger size clump which bloomed for you the year before (when you planted it, not when you dug it).

sylviatexas- i will check those other irsises I have. perhaps they went in too deep. they are in a neglected garden and perhaps they deserve a better spot. :)