Yin yang huo
What it is: This Chinese herb translates to “horny goat weed,” and is frequently the main ingredient in those sketchy behind-the-counter boner pills at bodegas. The plant itself is deciduous and found throughout Asia and in parts of the Mediterranean. Appropriately, its leaves are heart-shaped, and its four-petaled flowers can be white, pink, red, or yellow. Yin yang huo also goes by the name(s): barrenwort, bishop's hat, fairy wings, horny goat weed, rowdy lamb herb, and randy beef grass. Pick your favorite.
How it works: Yin yang huo contains icariin, a kind of PDE5 inhibitor that coaxes blood flow into smooth muscle. Sildenafil, the active ingredient of Viagra, is also a PDE5 inhibitor, and works precisely the same way as horny goat weed, it's just a whole lot more potent. As it happens, the original purpose of Viagra’s clinical trials were to test its viability as a heart medication by increasing cardiovascular blood flow. Presumably, someone was brave enough to stand up and confess that the medication seemed to have another effect.
How to grow it: Horny goat weed prefers a cool climate and shade, and grows anywhere from 6in to a foot (the plant, not you). Its roots demand richness, so add a few inches of peat moss or compost on top of the soil. Keep it moist, and trim away any leaves that crumple during the colder months.