If I could, I'd plant en entire mountain full of the kinds of flowers and grasses butterflies love. An entire country. As it is, I have a good number of bushes and flowers they enjoy, and they are drawn to them time and again, first as caterpillars (which is why I leave them and the ladybug larvae patches of stinging nettles, all-they-can-eat dandelions and the like) and finally, starting in this season, as butterflies. Many of the butterflies also greatly covet the cherries, but they leave the irises to me and the bees. 
As for bees, I hope to collect some honey this year, not from the wild bees, but from a couple of colonies my apiarist neighbor has kindly placed in the orchard and the garden. Signs look promising so far, and at least some of that honey will be derived from these irises, a number of which come from Cayeux.
Based in the Loiret, highly reputable Cayeux (the -x is silent) has been in business for four generations--over 100 years. In my garden, their irises--any iris--are extremely easy flowers to grow and ever so generous, requiring only a just-in-time sprinkle of organic (iron-based) anti-slug pellets to keep the strappy leaves from becoming uglified lace.
These flowers make visiting so inviting, how can a pollinator insect possibly resist?
They look like Frank Gehry's notion of a faerie dance hall.
Even before they open, there are intimations of something spectacular; the only down side to these flowers is that you can't eat them. 
You can, however, eat primroses, lavender, red poppies, roses, daylilies, marigold, nasturtium, violets, pansies, lilac, elderflowers, borage, and a whole host of flowers from common herbs, like sage, mint, and perhaps most commonly, chive. Only requirement: ensuring the blossoms you choose haven't been exposed to pesticides or other things you wouldn't want in your body. (The now week-old chicks can confirm the edibility of flowers...) 
For roses and other larger flowers, remember to remove the bitter white bit at the base of the petal. Don't expect too much taste from flowers, they're mostly there for color and charm. 
The herbal flowers usually taste a like more delicate version of the herb's leaves, with the exception of chive flowers, which are so powerful whole that they can taste like a raw onion. I learned this the hard way. Each chive blossom needs to be separated into lots of little flowerlets before being sprinkled into an omelet for delicious effect (none of the chives made it past the winter freeze, so I have no photos to share). I add a sprig of lavender to my lemonade, and it makes its way into a host of desserts, like ice cream. Violets and lilac are lovely atop cakes when sugared (and they keep for a good while, too.) Lilacs are another one of the flowers that does have a lot of flavor.
The herbal flowers usually taste a like more delicate version of the herb's leaves, with the exception of chive flowers, which are so powerful whole that they can taste like a raw onion. I learned this the hard way. Each chive blossom needs to be separated into lots of little flowerlets before being sprinkled into an omelet for delicious effect (none of the chives made it past the winter freeze, so I have no photos to share). I add a sprig of lavender to my lemonade, and it makes its way into a host of desserts, like ice cream. Violets and lilac are lovely atop cakes when sugared (and they keep for a good while, too.) Lilacs are another one of the flowers that does have a lot of flavor. In the photo above, a salad is simply dressed with balsamic vinegar and olive oil in the bowl given to me by my favorite butcher, a Moroccan, when I left Amsterdam. Scattered across the greens is an overly generous amount of blue borage, pale purple sage, red poppy, one purple sweet pea and a bit of yellow zinnia. I would have added primroses from the field, but it was getting late...and it was time to eat.
