In planning the backyard, a great flower choice for a Perennial is the Evening Pink Primrose, genus name is Oenothera and some time referred to as "Twlight". I believe at the time when my friend and I were shopping for her flower garden, we grabbed this flower because it was named TWLIGHT. Of course all you Stephanie Meyer fans know why. This flower looks stunning in a flower garden. It comes back every year. If your in the middle of planting flowers for your house then go out to your local Nursery or home improvement store and find this!