Overview: Oxalis humilis Thunb.
Oxalis humilis Thunb., commonly known as the Cape sorrel, is a small, creeping perennial plant belonging to the Oxalidaceae family. The plant is native to South Africa, but its cultivation has spread to many parts of the world such as Europe, North America, and Asia. It has been widely used for its medicinal properties, culinary purposes, and ornamental value, making it a popular plant among gardeners.
General Appearance
The Oxalis humilis Thunb. plant is characterized by its small shrubby growth and reaching up to 5-12 cm in height. It has trifoliate leaves, with each one consisting of three leaflets that are bright green, heart-shaped, and about 1 to 2.5 cm in length. The plant produces delicate pinkish-purple flowers that are about 1.5 to 2 cm in diameter and bloom in early spring. After flowering, it produces a small, dry, capsule-shaped fruit that contains tiny seeds.
Common Names
Oxalis humilis Thunb. is commonly known by several names such as Cape sorrel, Dwarf wood sorrel, Kenya sorrel, Sourgrass, and Oxalis deppei. These names reflect the plant's origin, characteristics, and uses.
Uses
The Oxalis humilis Thunb. plant has several uses, ranging from medicinal to culinary and ornamental purposes. In traditional medicine, the Cape sorrel plant is used as an herbal remedy for stomach aches, coughs, and fever. It also has anti-inflammatory and diuretic properties. In culinary applications, the leaves and stems of the plant are used in salads, soups, stews, and sauces. It has a sour and lemony taste, which makes it a popular ingredient for various dishes. Moreover, the plant is a favorite of gardeners and horticulturists because of its excellent ornamental value. It is commonly grown as a groundcover for its attractive foliage and delicate flowers and is suited to both indoor and outdoor settings.
In conclusion, the Oxalis humilis Thunb. plant is a versatile plant with numerous benefits and wide applications and is worth considering for both its aesthetic and practical uses.Light Requirements
Oxalis humilis Thunb. requires bright, indirect sunlight for healthy growth. Partial shade may also be tolerated, but direct sunlight must be avoided as it may scorch the leaves. In general, six to eight hours of bright, indirect sunlight is optimal for the plant.
Temperature Requirements
The plant is native to South America, where it grows in moderate temperatures. Oxalis humilis Thunb. prefers a temperature range of 60-75 degrees Fahrenheit (15-24 degrees Celsius). It should be protected from temperatures below 50 degrees Fahrenheit (10 degrees Celsius) and above 85 degrees Fahrenheit (29 degrees Celsius), which may cause stress and damage to the plant.
Soil Requirements
Oxalis humilis Thunb. thrives in well-draining, slightly acidic soil with a pH range between 5.5 and 6.5. The soil should be rich in organic matter and have good moisture retention capacity. It is recommended to use a high-quality potting mix with added perlite or sand to improve drainage. The plant should be watered regularly, but care should be taken to avoid overwatering, which can lead to root rot.
Cultivation of Oxalis humilis Thunb.
Oxalis humilis Thunb. is a small, low-growing plant that typically reaches a height of 10 to 20 cm. In terms of cultivation, it prefers well-drained soils that are rich in organic matter. It can be grown in containers or directly in the ground.
The plant prefers bright and indirect sunlight, so it is advisable to place it near a window or somewhere that receives a good amount of daylight. It can tolerate partial shade and high temperatures, but it is not frost tolerant.
Watering Needs of Oxalis humilis Thunb.
The watering needs of Oxalis humilis Thunb. are moderate. It is essential to keep the soil moist but not water-logged. The frequency of watering depends on the surrounding climate, temperature, and humidity. One should be careful not to water the plant too much during the colder months, as this can cause root-rot.
It is important to avoid getting water on the leaves or stems when watering this plant, as this can lead to fungal diseases. If the air in the surrounding area is relatively dry, it may be necessary to place a bowl of water near the plant to increase humidity levels.
Fertilization of Oxalis humilis Thunb.
It is advisable to fertilize this plant once a month, preferably with a balanced fertilizer. The fertilizer should contain sufficient amounts of nitrogen, phosphorus, and potassium to promote healthy growth. Over-fertilization may cause leaf drop, so it is essential to use fertilizers in moderation.
If the plant is grown in poor soil, one may choose to fertilize more frequently. During the winter months, when the plant is dormant, it is not necessary to fertilize.
Pruning Oxalis humilis Thunb.
Pruning is not strictly necessary for this plant, but it can be helpful in promoting bushier growth and preventing the plant from becoming too leggy. Pinching back the tips of stems a few times a year can encourage the plant to produce more compact growth.
Deadheading, or removing spent blooms, can also help promote a fuller growth habit. If the plant begins to produce too many runners, it may be necessary to prune back some of the stems to prevent overcrowding.
Propagation of Oxalis humilis Thunb.
Oxalis humilis Thunb. is a plant that reproduces both sexually and asexually. Some of the propagation methods are:
Seeds propagation
The seeds are obtained from the mature fruits, which are collected when they open spontaneously. They should be stored in a dry place until planting. The seeds need light to germinate, so they must be mixed with a substrate of fine sand or vermiculite. The substrate should always be damp, but not waterlogged, and the seedbed should be kept in a shaded and protected place until germination.
Bulbs propagation
The bulbs, also called tubers, are small fleshy structures that grow at the base of the stem. They can be separated from the main plant and planted individually. The best time to do this is during the dormant period, which occurs after the aerial part of the plant has died down. The bulbs should be buried just below the substrate surface, and a layer of mulch can be added to protect them.
Cuttings propagation
Cuttings can be taken from stems that have just finished blooming. The cuttings should be about 10 cm long and inserted into a substrate of damp sand or vermiculite up to half their length. They should be kept in a shaded place and watered regularly until they form new roots and shoots.
By using one or more of these propagation methods, it is possible to propagate Oxalis humilis Thunb. and obtain new plants that will produce crops of edible tubers.
Disease and Pest Management for Oxalis humilis Thunb.
Oxalis humilis Thunb., commonly known as the "Cape sorrel," is a perennial plant that is native to South Africa. This plant is known for its edible, tangy leaves, which can be a tasty addition to salads. However, like any other plant, Oxalis humilis Thunb. is vulnerable to diseases and pests. It is crucial to manage these problems carefully to ensure the plant's health and productivity.
Common Diseases
The most common disease that affects Oxalis humilis Thunb. is powdery mildew. This fungal disease appears as a powdery coating on the plant's leaves, stems, and flowers. It can cause stunted growth, reduced yield, and even death in severe cases. Another common disease is gray mold, which causes the plant's leaves to turn gray and dry out.
To manage powdery mildew and gray mold, it is crucial to maintain good airflow around the plant. Avoid watering the leaves and instead focus on water at the base of the plant. You may also consider using fungicides that are specifically designed for powdery mildew and gray mold. Proper sanitation practices, such as removing and destroying infected plant material, can also be helpful in managing these diseases.
Common Pests
Oxalis humilis Thunb. is vulnerable to several pests, including aphids, spider mites, and snails. Aphids are small, sap-sucking insects that can damage the plant's leaves and inhibit growth. Spider mites are tiny pests that can cause significant damage to the plant's leaves, causing them to appear speckled and discolored. Snails can also be a significant problem, particularly for young Oxalis humilis Thunb. plants, as they can consume the entire plant in just a matter of days.
To manage these pests, you may consider using insecticidal soaps or oils that are designed for aphids and spider mites. Regularly inspecting the plant for signs of pests and promptly removing them can also help prevent infestations. Place snail traps or barriers around the plant to prevent snails from reaching the plant.
In conclusion, managing diseases and pests is crucial for the health and productivity of Oxalis humilis Thunb. Proper maintenance practices, such as good airflow, proper sanitation, and timely pest and disease management, can help ensure that the plant thrives and produces high-quality, edible leaves.
