most folks eat the flowers before they're opened. at that stage, they can be harvested and dried for storage. I don't think they're as tasty once they bloom. I believe the roots are about the same all the time, but I'm not sure about that. roots have the stronger flavor which might be an acquired taste.
hobbssamuelj wrote: What would outcompete common day lillies? There are literally hundreds in a gerden bed next to my driveway. I think this would be a perfect place for raspberries.
It dawned on me that there is no need and both might be able to co-exist happily. The raspberries will have to have vines trained onto 2 wires, the lilies can grow underneath the wires thus keeping your soil. Dividing the lilies every few years is part of having perennials like these. Perhaps you can sell them on something like Craigslist or give to your neighbors, etc.
Btw, fill the flowers with goat cheese, batter the whole thing up, and lightly deep fry for a yummy treat. Oh wait, was thinking squash blossoms.
In the designers manual, Mollison has a picture of canna lilly as part of a grass barrier, coupled with comfrey and lemon grass. Looks like he puts the comfrey at the far edge against the grass, but I can't tell from the picture whether the lilly is in the middle or the lemon grass.
Not sure how your garden is set up but maybe consider transplanting them at the edge of your garden?