Oxalis triangularis is native to South America, particularly Brazil, where it thrives in the tropical rainforests. This environment provides it with the warm, humid conditions it favors. The plant was first scientifically described and named in the 19th century. Its common name “Shamrock” or “False Shamrock” stems from the resemblance of its leaves to the Irish shamrock, although they are not botanically related (the true shamrock is typically a species of clover, Trifolium).
Characteristics
- Foliage: The plant is known for its distinctive clover-like leaves, which are actually composed of three heart-shaped leaflets arranged in a triangular pattern. These leaves are typically a deep purple or burgundy color, though green varieties exist. The leaves exhibit nyctinasty, folding up at night or in low light, which is a fascinating trait for observers.
- Flowers: Oxalis triangularis produces small, delicate flowers that can range in color from white to light pink, often blooming on slender stalks above the foliage. The flowers are trumpet-shaped and appear in clusters.
- Growth Habit: It’s a perennial herbaceous plant with an underground rhizome or bulb-like structure from which new growth emerges. It can reach heights of about 6-12 inches (15-30 cm) when grown indoors.
- Light Response: The plant’s leaves open up in the morning to absorb sunlight and close at night, a behavior known as photonasty. This characteristic makes it quite interactive, responding visibly to changes in light conditions.
- Toxicity: All parts of Oxalis triangularis contain oxalic acid, which can be toxic to pets if ingested in large quantities, leading to symptoms like vomiting or diarrhea. For humans, while the plant is edible in small amounts (used in salads for its sour taste), excessive consumption can lead to health issues due to the oxalic acid content.
Cultivation
- Light: Prefers bright, indirect light. Direct sunlight can cause leaf burn, but too little light will result in leggy growth or the plant not opening its leaves fully.
- Temperature: Thrives in temperatures between 60-75°F (15-24°C). It can tolerate slightly cooler conditions at night but is sensitive to frost.
- Humidity: Enjoys moderate to high humidity, which is often achieved by misting or using a pebble tray with water under the pot or placing the plant in naturally humid areas like bathrooms or kitchens.
- Soil: Requires well-draining soil. A mix of potting soil with perlite or sand helps prevent root rot. The plant prefers slightly acidic to neutral pH.
- Watering: Water thoroughly when the top inch of soil feels dry, but avoid overwatering. During its dormancy period, reduce watering significantly.
- Fertilization: Feed with a balanced, water-soluble fertilizer once a month during the growing season (spring and summer). Avoid fertilizing during dormancy.
- Dormancy: Oxalis triangularis has a natural dormancy period where it might shed its leaves. This can occur after flowering or in response to stress like extreme temperatures or inadequate light. During dormancy, watering should be minimized until new growth appears.
- Pests and Diseases: Generally resistant but watch for aphids, spider mites, or fungal issues if overwatered. Good air circulation and not letting the plant sit in water can prevent most problems.
- Propagation: Easily propagated by division of the rhizomes or bulbs during repotting. Cuttings can also work, but division is more common and reliable.
- Repotting: Repot annually or when the plant becomes root-bound, using fresh potting mix.