I'm not 100% sure, but to me it looks like common milkweed. Asclepius syriaca. Monarchs do like them a lot, drinking the sweet nectar and laying their eggs on them. There are a few other milkweeds that look similar, but I'm going with the common milkweed.

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Probably right. I would guess the same. Thanks. How and when do monarchs use them in MI. Any particular time of the year?

Abrahamx, I'm about as far north as you are. The Monarchs that make their way up here are second or third generation, so I don't usually see any in spring. They usually appear in mid to late July. They lay eggs, and the adults from those eggs fly north to Canada. The offspring of those northernmost Monarchs are the ones that migrate to Mexico. The North American Monarch population has dwindled severely over the last couple decades, making sightings a very rare thing, at least in my area. 50 years ago, I remember that almost every common milkweed I walked to, had at least one Monarch caterpillar. Today I can pass miles and miles of milkweeds without ever seeing one cat. 50 years ago the numbers of all butterfly species was abundant and the Zebra Swallowtails, Fritillaries,and Mourning Cloaks were in the area, but today those species are never seen. Paw Paw is rarely grown by people this far north, which may be one of the reasons why Zebras are't seen.

It's a perennial so it comes back every year. It will grow this year, flower and produce seeds. Those seeds may self-sow and you may get a larger patch of milkweed (or you can save seed and plant more). I love the pink flowers.