These are 15 plants in roughly a 2 foot diameter plot. I planted them tightly to create a bush type of effect. The blossoms have just started opening in the last few days. They should get twice as tall, while continuing to bloom, through the end of the growing season. This is my favorite milkweed for the monarch butterflies to lay their eggs on. I think the slender green leaves, although sparse, look nicer than others I have planted. Also, it is non-invasive; the plants and seeds do not survive the cold temps of winter here.