A leaning Saguaro cactus study from Barcelona botanical gardens. The Saguaro cactus can grow up to 12 meters tall and is one of the more 'tree like' cacti. The Saguaro cacti are a common sight in Mexico and the Arizona dessert. They play a vital role in the health of the desert by replenishing the fertility of the soil when the cactus eventually decomposes. Gouache painting on A4 watercolour paper, 300 gsm.