Native to northeastern Brazil, Pilosocereus pachycladus is a stunningly beautiful columnar which can grow to 30 feet tall in the wild. Hopefully not in a pot! The contrast between the sky blue bloom on the stems and the golden spines is striking. They have white blooms with reddish outer segments and reddish purple fruit.
     I think this my favorite columnar cacti. This is my first one, bought last spring from Bachs Cactus Nursery here in Tucson. I don't know if it's the large pot I put it in or if they simply grow like crazy. But as you can see it's tripled in size to almost 18 inches in one season. I'm looking forward to what it will do this year. I also came across a potfull of smaller ones at Home Depot, split them up and put a couple in the ground. They survived their first winter just fine. Below is some older pics of the beauty above.

The same plant just potted a year ago

After about a month

Mid summer