It's dark now, but I can shoot another photo tomorrow. Meanwhile, here's another, just zoomed in and cropped:

Got milk?

Linnea, I'm pretty sure its a milkweed species. There are 140 different native milkweeds. Most people think of common milkweed, Asclepius syriaca as the stereotypical milkweed because thats the one they see the most. Some of the other milkweeds look totally different compared with common milkweed. Your plant is another milkweed species. If you rip a leaf you should see white, milky sap. Your plant isn't swamp milkweed, (A. incarnata) either. I can't give you an exact i.d., but you have something like Asclepius ovalifolia or Asclepius speciosa, or Asclepius sullivantii. They are not as common as the common milkweed, and are highly valued by milkweed gardeners. Your photo is good, no need to take another. I wouldn't pull them. I have a few common milkweeds that were volunteers, and I just noticed several Monarch butterfly caterpillars on them. A female Monarch may soon fly through your yard, and lay eggs on your beautiful milkweeds. Oh, and by the way, don't freak out if you see the leaves chewed. I thought earwigs were eating my milkweeds, but it was Monarch caterpillars which is what I was hoping for anyways.

Thanks, Jay! By strange coincidence, I was given some common milkweed seeds by a fellow gardener this spring. I had not gotten around to planting them. And here I have a volunteer of another variety!

Are they perennials or annuals? It's actually blocking a few flowers, I was thinking of moving it. If it's a perennial, I might move it in fall, once it gets some attention (hopefully) from a monarch and caterpillars are raised.

I normally see quite a few butterflies in my yard, but only once - too far away to judge - one that could have been a monarch.

> thinking of moving it

Established tap root plants often do poorly after transplantation;
definitely is so for Asclepias(still conjecture until you
produce the evidence).

Your milkweed plants look very healthy. They might flower and make seed. Wait till fall to move. I'm still trying to i.d. what type of milkweed you have. The way each set of leaves is 90% off axis from the previous set of leaves should be a clue. It's also very cool looking.

Linnea, I've been looking at different milkweeds, and the closest match I can find is Prairie Milkweed, Asclepius sullivantii. This species has pink flowers very similar to common milkweed.

I forgot to break a leaf today, to see if it oozes anything milky, but so far, no flower buds yet.

It passed the milky sap test, but still, no flowers!

I'm starting to think your plant is a dogbane, Apocynum. They are closely related to milkweeds, and they also have the milky sap. Sorry if I was in error, the 2 genera are often hard to tell apart. Dogbanes can bloom all the way into September. I included a couple photos of dogbanes, Apocynum, that resemble your plant.

Linnea, after looking at the photos, what do you think?

Maybe I can tell when it flowers? I assume monarchs do not lay on dogbane? I have seen no monarchs in the yard. Few butterflies at all this year.

The flowers would be white if it's dogbane. Monarchs don't lay their eggs on them, but Hummingbird Clearwing Moths do.

I have had few butterflies, but have seen hummingbird moths several times, in the garden on the opposite side of the house. Thanks!