As beautiful as they are to our eyes, some horticulturally “improved” varieties of garden flowers just aren’t as attractive to bees, butterflies, and other insects. Doubled petals, in particular, may block access to nectaries or pollen.
Several studies have shown that the explosion of petals that may delight gardeners can actually reduce the attractiveness of that flower to pollinators. This may be a result of lower nectar production as the plant puts its energy into making petals or it may be simply that the insects can’t get to the nectar or pollen.
If you think a beautiful flower is one with a bee or butterfly on it, choose the simpler single blossoms as you make your plant selections.