Also known as Swamp milkweed, this North American native bears bright pink-and-red, vanilla-scented flowers in June and July. Surprisingly adaptable, this 5-foot-tall perennial is the preferred forage source for the larvae of Monarch butterflies and can grow in wet to well-drained soil. Perennial. Hardy to zone 4.

Images and description courtesy of Seed Savers Exchange/ seedsavers.org