I started my canna pretorias this week indoors and some of my other canna bulbs are sprouting now, so I will be planting them soon in pots, or waiting to starting them outside. I usually start them outside in early april and by then they are pushing out there first leaves. Typically I get my first flowers at the end of june or early july and the most flowers occur in late july to mid august. And they LOVE lots of water (rain water in especially) when its hot so that usually makes it bloom a little earlier.

Good luck!

Cannas are hardy to zone 7 and above - if you plant them in the ground and mulch them, they will spread for you.

Ive tried overwintering them many times they alwys rot by spring

Me too, I think it has to do with the clay soil, but if mulched well and kept dry, they should make it. I wouldn't risk them all though and since they are easily dug up, I dont mind to.
good luck!

are you sure your zone 7?
staten island is listed as 6 under this link

Here is a link that might be useful: zone finder

Staten island is a zone 7 and has not approached 0F in many years (I think the last time they were below 5F was in the early 2000's). I just dont think the USDA zone map acknowledges that small of an area or its microclimate. I have seen many zone 7 plants like camellias, crape myrtles, and southern magnolias thrive in the NYC area with no protection, some very old, and they would do poorly in a zone 6. I think of cannas as more zone 8 plants but the winter moisture usually rots them north of that.

Yeah I think they may need to re-do those zone maps.
Our lowest temps were in the high teens this year and zone 5b/6a on the zone map is about -10 to -20
and we actually got more snow fall this year than average so not sure what's going on with our climate these days!

accoding to the arbor day foundation my zipcode 10312 is zone 7. Our winter lows are ussualy between 5-15. this winter we only had 14

Here is a link that might be useful: http://www.arborday.org/treeinfo/zonelookup.cfm

We are definitely due for a new, more accurate, USDA map.

I have always found that Canna does better when it's kept in growth all year round and not allowed to go dormant. I also grew it in England that way btw.That is the way it grows here and you can see it in almost every other garden, nearly always in flower. I guess you would need a heated greenhouse for this, however, in your parts. Though you could, as I did, keep it a sunny room inside the house. Watch out for those durn spider mites, however.

Cannas need sun and heat, and sprout pretty quickly once the rhizomes are planted so unless you have a sunny spot for them I wouldn't recommend starting them indoors any more than two or three weeks prior to putting them outdoors--in my area, early May.

I'm in a solid zone 7a, maybe even 7b, and cannas have NEVER been hardy for me, although I know plenty of people in my area who claim they overwinter pretty regularly. After losing a couple of choice cannas this way I now dig up at least a few rhizomes in the fall and store them indoors. I store the rhizomes bone-dry in a cool room over the winter; I've never had trouble with either rot or premature sprouting. Some cannas have thin, ropey rhizomes and aren't as reliable this way, but it works quite well for the ones with the big fat rhizomes.