Monarch butterflies flitter on both sides of the Rockies, and that mountainous divide is where things got interesting in the wake of last week’s “Tropical Milkweed” article. Immediately after Carolina Starin’s piece warning of parasites in the tropical variety (A. curassavica) appeared, Ward Johnson, of Minneapolis’s Save Our Monarchs, posted a comment offering eastern milkweed seed (A. incarnata). An exchange about natives, native-to-where, and tropical milkweed followed between Johnson and Bob Danziger, a composer in Carmel whose Brandenburg 300 Project — dedicated to Bach’s concertos — supports the Pacific Grove Museum of Natural History’s California milkweed (A. fascicularis) program. It’s free, it prevents parasites, it feeds pollinators, and you can get some here: pgmuseum.org/free-seed-distributions.