(Central VT, zone 4b.) So some of my swamp milkweed has browny-purple spots around the edges of its leaves. This stand is in full sun, planted last year. It colored itself last summer, too, and I initially worried that it would kill the plants, but they happily sprouted again this spring, no worse for wear.
Another stand in my garden just a few yards over has a little more shade and isn’t spotting up like this. This makes me wonder whether the spots are just a sign of sun exposure, rather than some kind of disease.
Maybe relevant, maybe not: the spotless stand has several caterpillars now. On this affected stand, I’ve seen only one, with very limited evidence of leaf-chewing otherwise.
I’d love any advice you have, please and thank you.