Plants with dark foliage are highly dramatic. Their flowers stand out like no others due to the backdrop of their tenebrous leaves. Although plants are sometimes selected and bred for darker foliage solely for ornamental purposes, there are distinct physiological advantages to plants that have it.In nature, plants with extremely dark foliage are nearly always shade dwellers. Even plants with dark red or purple undersides — indoor plants such as Calatheas and Marantas come to mind — thrive in environments with limited light.  Dark foliage absorbs every bit of light that reaches it, as opposed to green-leaved plants that absorb...