The Toothpick Cactus grows to a height of between 15 to 25 feet and is often a jumble of arms in every direction. However, it produces the most exquisite white blooms. Contrary to most cactus, it blooms most of the year. The fullest display is in the spring but I've seen blooms well into the winter months.
If you look closely in this photo, you can see a bloom near the very top and center and another one straight down near the middle of the photo. There are several more visible in that jumble of thorns.