Pachycereus pringlei (Mexican Giant Cardon) Cactus Seeds (100 Seeds). The Giant Cardon is the tallest cactus species in the world, with a maximum recorded height of 19.2 m (63 ft), with a stout trunk up to 1 m (3.3 ft) in diameter bearing several erect branches. Similarly to the related Saguaro, it is a slow-growing plant, with a lifespan measured in hundreds of years.