Trichocereus pachanoi or San Pedro is an upright columnar cactus native to Ecuador and Peru. In nature, the cactus will reach up to 20 feet (6 m) tall with a spread of about 6 feet (2 m). Stems are photosynthetic, light to dark green, and may be glaucous when young. Plants have 6-8 well rounded ribs with highly variable spines. Some stems have essentially no spines, but others have as many as 3-7 yellow to brown spines, 0.75 inches (2 cm) long, on each podarium. The first cutting that we received did not have spines, but after several years of growing it, one of the branches broke off; once rooted, it started producing spines. Plants are very easy to grow and are hardy in the landscape down to 15°F (-9°C).
Blooming: The cactus blooms in early July in the greenhouse with nocturnal white flowers that are very fragrant. Flowers are up to 9 inches (22.5 cm) long. They are very showy.
Culture: Trichocereus pachanoi need full sun to light shade, with a rich, well drained soil mix. In the greenhouse, we use a soil mix consisting of 2 parts peat moss to 2 parts loam to 2 parts sand with small gravel added to ensure good drainage. We water the plants well and allow them to dry before watering again. This species seems to do better with a little more water than most cacti. During the growing season, we fertilize them monthly with a balanced fertilizer. During Oklahoma's hot summers, the cactus are subject to sun burning, so we grow them under 25% shade all year long. During the winter month, the plants are kept in the cool room and nighttime temperature are kept at 48°F (9°C).
Propagation: Trichocereus pachanoi are propagated by cutting or from seed when available.
Trichocereus pachanoi was featured as Plant of the Week March 16-21, 2007.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.