Added Jun 15 2018
For anyone interested in helping restore Monarchs by planting milkweed; not all milkweed offers full life-cycle Monarch support (not all gardeners/naturalists know the distinction). All types of milkweed will attract pollinators/butterflies.
But only Common Milkweed (Asclepias syriaca) supports the full Monarch lifecycle; as the necessary food source for caterpillars of the Monarch butterfly that feast on its leaves.
Never saw the visitor to our garden, but we found its caterpillars! (pic)