Milkweed. Even if you let a few grow in the garden it does help. It is very easy to weed out or just dead head the flowers.
Milkweed is a common folk remedy used for removing warts. Milkweed sap is applied directly to the wart several times daily until the wart falls off. Dandelions sap is often used in the same manner.
Milkweed is beneficial to nearby plants, repelling some pests, especially wire-warms.
Milkweed also contains cardiac glycoside poisons which inhibit animal cells from maintaining a proper K+, Ca+ concentration gradient. As a result many natives of South America and Africa used arrows poisoned with these glycosides to fight and hunt more effectively. Milkweed is toxic and may cause death when animals consume 1/10 its body weight in any part of the plant. Milkweed also causes mild dermatitis in some who come in contact with it.
Milkweed sap is also externally used as a natural remedy for Poison Ivy.
why you should grow it
Being the sole food source of Monarch Butter-fly larva, the plant is often used in Butter-fly Gardening