Pilosocereus pachycladus (Blue Torch) Cactus Seeds (100 Seeds). Pilosocereus pachycladus  is one of the most spectacular, columnar, tree-like cacti. It can grow up 33 feet tall (10m) or more. The base develops a distinctive trunk with dozens of erected glaucous (bluish-silver) branches. The stems are turquoise or light blue-green. The spines are translucent with a yellow hue. This is one of the bluest of the columnar cacti.