Myrtillocactus geometrizans is a large shrubby cactus growing to 4–5 m tall, with candelabra-like branching on mature plants - hence it's name ""Blue Candle Cactus".
It's a beautiful plant that's perfect for cacti collectors and beginner-plant-parents. This guy is related to the super-popular Boobie Cactus. It's areoles just aren't as big, giving it a smoother, less boobie appearance.
(Areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants.)
Water more in the summer months, making sure the soil is dry to touch before giving it a drink. Leave dry in the winter months.