| What a great Valentine idea! I guess it's possible that they froze, but canna rhizomes are pretty hardy; mine stay in the ground year-round, & they've survived 9-degree nights that I know of. can't help on the toxicity question, but...
cannas are in every grandmother's garden around here, everybody I know grew up with them, & we're all still here! Lots of plants, like oleanders are "poison" if ingested, so, uh, don't eat 'em. Hope your wife liked the cannas! | 
