It is a large shrubby cactus growing to 4–5 m tall, with candelabra-like branching on mature plants. The individual stems are 6–10 cm diameter, with five (occasionally six) ribs, with areoles spaced 1.5–3 cm apart. The flowers are creamy white, 2–2.5 cm diameter. The fruit is an edible dark purple berry 1–2 cm diameter, superficially resembling Vaccinium myrtillus (Bilberry or Whortleberry) fruit; both the scientific and English names derive from this resemblance.
It is a popular species in cultivation, where young plants commonly remain unbranched for many years. The fruit edible, and sold for consumption in Mexico.
The cactus is fast growing, and is often used as grafting stock because of this. It can reach heights of up to 1.2 metres, although commonly only growing to around 10" (about 26 cm).