We scattered edible white borage flowers over this summer salad--you can use any variety of pretty blooms you like: lavender, elderberry, chive or squash blossoms, chamomile, and violets.
Whisk together lemon zest and juice, thyme, syrup, mustard, salt, and pepper in a large bowl. Let stand 15 minutes. Whisk in oil. Add butter beans, peas, tarragon, and shallot; toss to coat. Place in a large serving bowl. Sprinkle with flowers, if desired.