For the dressing: Put all the ingredients into a small bowl or jam jar. Whisk with a fork until the dressing has emulsified.
For the salad: Wash and dry the lettuce and salad leaves. If large, tear into bite-size bits. Put in a deep salad bowl and add the herb sprigs and edible flowers. Toss, cover, and chill in a refrigerator until needed. Just before serving toss the salad in just enough dressing to make the leaves glisten, save the remainder of the dressing for another day.