I've seen dried rose petals in bulk in the spice section at Mississippi Market. Beautiful colors.
But they don't look like fresh whole petals. More like dried fragments. I can look again next time I'm there in the next few days.
The colors are pretty. I've used them as decorations on valentines day cakes and cupcakes to good effect.
I'm looking for edible violets and I've been told to check at the farmer's market, but of course edible flowers are out of season this time of year and probably extra hard to find.
Maybe check with a caterer or someone who makes wedding cakes? They seem to be the main consumers...
Oh, this is a tough one - especially in January!
My only thought is to call one of the big co-ops in the Twin Cities - like the Wedge - and talk to the produce manager to see if he/she has any suggestions. They carry edible dried lavender, so they might have a source for other edible flowers. Now that I think of it, I've occasionally seen edible flowers in the fresh herbs section - pansies, nasturtiums, and the like - but only in mid-summer. (I think they were packaged by Dehn's Garden, who do a lot of fresh herbs.)
This time of year, perhaps you'll need to find a South American source? I found an interesting article on Huffington Post about how Ecuador is gearing up for a boom in edible roses - google "edible roses on the rise" and you'll find it, too. But it doesn't help with any specifics on buying the durned things!