Oxalis herrerae, a distinct species within the large Oxalis genus, offers unique ornamental appeal for plant enthusiasts. Unlike many of its common relatives, this plant presents an unusual form with attractive foliage and delicate flowers. Its distinctive characteristics make it a captivating addition to various plant collections.
Understanding Oxalis herrerae
Oxalis herrerae is a perennial shrub with a unique appearance, growing up to 3 feet tall and wide with proper care. It features stout, succulent stems and light green trifoliate leaves. A particularly interesting detail is the swollen, succulent petiole, which can turn a greenish-pink hue, leading to its common names like Oxalis teneriensis or Oxalis coralleoides.
This plant produces acid yellow, 1-inch flowers that emerge at the top of the branches. Blooming occurs throughout the year, most prolifically in spring and summer. Native to Peru and Ecuador, it thrives on dry, rocky, stony slopes at altitudes of 2,200 to 3,200 meters.
Cultivating Oxalis herrerae
Successful cultivation involves understanding its specific environmental preferences. This plant thrives in bright, indirect sunlight, though it can tolerate some direct morning sun. If placed outdoors, it should be in a shaded area to prevent scorching. Indoors, a south-facing window with filtered light or an east/west-facing window is often suitable.
The plant prefers well-draining soil, similar to what succulents require. A good soil mix can consist of less than 30% organic matter, such as a 2:1 blend of cactus/succulent potting soil and pumice, perlite, or lava rock. While it can adapt to various soil conditions, avoiding saturated soil is important to prevent root rot.
Watering requires allowing the top inch or two of soil to dry out completely between waterings. It tolerates drier conditions; drooping or wrinkling leaves indicate a need for water. During the growing season (spring and summer), water more frequently; reduce significantly in cooler months or dormancy.
It prefers stable room temperatures, ideally 60°F to 75°F (15°C to 24°C). While it tolerates brief periods outside this range, prolonged exposure to extremes causes stress. It appreciates moderate humidity, maintainable with a humidifier or pebble tray in dry indoor environments.
During its active growing season (spring and summer), fertilize once a month with a balanced liquid fertilizer, such as an NPK 10-10-10 formula. Reduce or cease fertilization during its dormant period (fall and winter). Nitrogen-rich fertilizers help maintain lush foliage.
Propagation and Dormancy
Propagate through stem cuttings. Allow cuttings to sit for a few hours before placing them in fast-draining soil. Unlike many Oxalis species, this plant does not typically form bulbs.
It can enter a dormant phase, especially if exposed to dry circumstances or cooler temperatures. During dormancy, the plant may lose its leaves, revealing its succulent stems. If dormant, reduce watering significantly, keeping the soil barely moist until new growth appears.
Common Issues and Solutions
It is generally resilient, but issues can arise from improper care or pests. Yellowing leaves often indicate overwatering or nutrient deficiency. Consistently wet soil with yellowing leaves suggests overwatering, which can lead to root rot. Allowing the top inch of soil to dry between waterings and ensuring proper drainage prevents this.
Pests like aphids, spider mites, and mealybugs can affect it. These pests feed on plant sap, causing yellowing leaves and stunted growth. Regular inspection and prompt treatment with insecticidal soap or neem oil manage infestations. Improving air circulation also deters fungal issues like powdery mildew, which appears as a white coating on leaves and thrives in warm, dry conditions.