Blue Candle Crested Cactus | Myrtillocactus Geometrizans , Rare Cactus in 4'', 6'', 8'' potAppearance: The blue candle cactus has a columnar shape, with a thick stem that can reach up to 12 inches (30 cm) in diameter. The stem is blue green in color and has deep, prominent ribs running vertically along its surface. These ribs give the cactus a unique geometric pattern. The stem is covered in small, sharp spines that can be up to 1 inch (2. 5 cm) long. Growth: The blue candle cactus can grow up to 30 feet (9 meters) tall in its natural