My husband just put a planter box under an Oak tree in my back yard. It is mostly shaded except for a few hours in the late afternoon when it gets some sunlight mostly on the west side. I want flowers as (colorful as possible) that are relatively easy to care for and if possible will attract butterflies. I do not in any way have a "green thumb," so any and all help would be appreciated. Like I said, I have no clue what flowers like sun or shade. I am asking for what type (names please) of flowers I should ask for at the store.