I have a 6 potted milkweeds, and one in the ground which gets full all day sun. The one in the ground by far grows the smallest leaves, the rest get varying times of shade and sun and have double sized leaves as the potted one. One of my potted plants is completely under a shaded arbor and the leaves on this one are a very dark green and about four times the size of the leaves on the others in the shade/sun areas. I had given seeds to my Dad who planted them in a completely shady spot and I noticed how really large his leaves were. Anyone else notice this?