Oxalis triangularis

Oxalis, also known as wood sorrels, is a large genus of flowering plants in the family Oxalidaceae comprising about 570 species. The name ‘Oxalis’ is derived from the Greek word ‘oxys’, which means ‘acid’ or ‘sharp’, referring to the sharp taste of the plant’s leaves. These plants are known for their clover-like leaves and attractive flowers.

Many Oxalis species are considered weeds, especially the creeping wood sorrel (O. corniculata) and Bermuda buttercup (O. pes-caprae). Some cultivated species, especially O. tetraphylla and O. deppei, are popular as ornamental plants.

The genus name Oxalis comes from the Greek word oxys, meaning “sour” or “acid”, referring to the sour taste of the leaves. The sour taste comes from oxalic acid, which is toxic in large amounts but present in safe quantities in Oxalis species.

The basic chromosome number of the genus is 10. Some species are diploid with 2n = 20 chromosomes, while others are tetraploid with 2n = 40 chromosomes. A few species have higher ploidy levels.

Types of Oxalis:

– Common Yellow Wood Sorrel (Oxalis stricta): This is a common and widespread species with yellow flowers and clover-like leaves. It is considered a weed in some areas.
– Purple Shamrock (Oxalis triangularis): This popular houseplant has purple leaves and delicate pink or white flowers. It is known for its striking foliage.
– Cape Sorrel (Oxalis capensis): Native to South Africa, this species has small pink or white flowers and spreads rapidly, making it suitable as a ground cover.
– Irish Shamrock (Oxalis acetosella): Native to Europe, this species has three-leafed clover-like leaves and delicate white flowers.

Growing Oxalis:

– Light: Most Oxalis varieties prefer bright, indirect light. Some species, like the Purple Shamrock, can tolerate partial shade.
– Soil: Well-draining soil is essential for Oxalis plants. A mix of potting soil, peat moss, and perlite is suitable for container planting.
– Watering: Oxalis plants prefer evenly moist soil. Water them when the top inch of soil feels dry, but avoid overwatering as it can cause root rot.
– Temperature: Oxalis plants thrive in temperatures between 60°F and 75°F (15°C to 24°C). Some species can tolerate cooler temperatures.
– Indoor vs. Outdoor: Most Oxalis varieties can be grown indoors and outdoors. However, they may need protection from frost if grown outdoors in colder climates.

Care and Maintenance:

Fertilizer:

Use a balanced, water-soluble fertilizer diluted to half-strength during the growing season. Avoid over-fertilization, as it can lead to leggy growth.

Propagation:

Oxalis can be propagated by seeds, division, or bulb offsets, depending on the species. The plants are often self-seed and can spread rapidly in favorable conditions.

Pruning:

Remove dead or yellowing leaves regularly to keep the plant tidy. Some Oxalis varieties may benefit from periodic trimming to encourage bushier growth.

Pests and Diseases:

Oxalis plants are generally not prone to serious pest or disease issues. However, they can be affected by aphids, spider mites, or fungal diseases in humid conditions. Treat any infestations promptly.

Dormancy:

Some Oxalis species, such as the Purple Shamrock, go through a period of dormancy. During this time, reduce watering and place the plant in a fabulous, dark location. New growth will emerge when the dormancy period is over.

Symbolism and Uses:

– Oxalis plants are often associated with good luck, faith, and love.
– Some Oxalis species, like the Irish Shamrock, hold cultural and symbolic significance in Ireland and are associated with St. Patrick’s Day.
– The leaves of certain Oxalis species, such as the Common Yellow Wood Sorrel, have a tart, lemony flavour and can be used in salads or as a garnish.

Toxicity:

While the leaves of Oxalis are edible in small amounts, they contain oxalic acid, which can be harmful if consumed in large quantities. Oxalic acid can cause kidney stones and other health problems.

Conservation:

Many species of Oxalis are common and not threatened, but some are rare and endangered, often due to habitat loss.

In conclusion, Oxalis is a diverse and fascinating genus of plants with a wide range of uses and characteristics. Whether you’re interested in gardening, botany, or natural history, an Oxalis species will likely catch your interest.