Balsam (Impatiens balsamia)

Annual
Much loved by cottage gardeners, this plant thrives in part-shade or sun, and sports double rose-like flowers in white, pink, red, salmon or violet all up the stem, at the leaf axils. Mature seed pods will explode when touched or gently squeezed – fun for kids and adults, too!
To grow: best to start indoors and transplant outdoors when all danger of frost has passed. Space about a foot apart. Needs rich, well-drained soil to do best. Self-seeds conservatively; grows to 2.5'