Black Ace turtlehead is a perennial that gets its name from its dark leaves. The white flowers, which appear from July through October, are said to resemble a turtle with its mouth open but are more reminiscent of snapdragons. It grows 3-4 feet and prefers wet soil in part shade where it will attract butterflies. Native to North America, it is a host plant for the Baltimore Checkerspot butterfly. Cut it back in the spring to reduce the height or it may flop and need support. It is an ideal plant for the rain garden where it will spread slowly by rhizomes.