Oxalis rubra or Windowbox Wood Sorrel, a native of Brazil, is the most common Oxalis in cultivation. It has a thick, woody crown and a tuber that will reach up to 12 inches (~30 cm) in containers. It is a great plant for the windowsill garden and is very showy when in flower.
Blooming Time: From June - September, the plant is adorned with pink- to lilac-colored flowers with darker veins. The cymes have any where from 8 to 12, 3/4-inch (~2 cm) flowers.
Culture: Oxalis rubra is easy to culture requiring warm temperatures with full sun to about 25% shade. One of the most common reasons for not flowering is not enough light. In the greenhouse, we use a soil mix consisting of 2 parts peat moss to 2 parts loam to 1 part sand or perlite. The soil should be kept moist at all times for optimum growth and flowering. They should be fertilized on a weekly basis during the growing and flowering season. Even though they are evergreen, water should be restricted during the winter months so that the tuber do not rot. Tubers should be stored at 40° F (~4° C) and replanted in the spring.
Propagation: Oxalis rubra is propagated by division in spring.
Oxalis rubra was featured as Plant of the Week June 21-27, 2002.
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.