Look very healthy! But this must be a strain of milkweed that is unique to your area or maybe this strain is different than northern strain milkweed? Yours looks like it has a woody stem and thin, flat more veined leaves.
Our milkweed has a soft green fragile stem that oozes milky fluid if bruised. The leaves are wider and thicker. I should find and try to post a picture. see attached but our milkweed in the fields and ditches look different than these pictures too. Maybe they color up more in the fall.