Hoya AH 'Black Magic' is an eye-catching Hoya famous for its bewitching, dark foliage. Its most fascinating trait is that its striking, near-black leaves are actually a natural stress response known as "sun-stressing." When exposed to bright, indirect light, the plant produces extra anthocyanin (a protective purple pigment) to defend itself from UV rays, turning the Hoya leaves an incredibly deep, dramatic shade.