It carries a parasite of Monarch Butterflies referred to as Ophryocystis elektroscirrha, or OE, which might result in defects within the wings of Monarchs. Since it doesn’t die again and might bloom late, the plant itself might also confuse Monarchs by signaling a breeding time when it’s time to migrate. https://modernbookmarks.com/story18202014/the-ultimate-guide-to-are-milkweeds-perennials-or-annuals