Origin
Lachnaea nervosa (Thunb.) Meisn. is a species of flowering plant that belongs to the family Asteraceae. It is native to East Asia, specifically found in China, Japan, Korea, and Taiwan.
Common Names
The plant is commonly known as Shi-mian-ying in China, Sabinokishimenso in Japan, and Chimyunamul in Korea.
Uses
Lachnaea nervosa has a variety of medicinal uses. In traditional Chinese medicine, the root of the plant is used to treat rheumatism, bruises, and swelling, while the leaves are used to treat coughs and fever. In Korean folk medicine, the dried leaves are used to make tea which is believed to help with indigestion and fatigue. The plant is also used as a folk remedy in Japan for urinary tract infections.
General Appearance
Lachnaea nervosa is a perennial herb that grows up to 60 cm in height. The leaves are alternate, elliptic to ovate in shape, and measure 5-10 cm in length and 3-6 cm in width. They are velvety and hairy on both sides. The flowers are small and yellow, and they bloom from August to September. The fruit is a small achene with a long pappus that helps it to scatter by the wind.
Light Requirements
Lachnaea nervosa (Thunb.) Meisn. typically prefers shade to partial shade. Direct sunlight may cause leaf scorching, and the plant may not grow as well in areas with full sun exposure. In their natural habitat, they are often found growing under trees or in other shaded areas.
Temperature Requirements
The ideal temperature for Lachnaea nervosa (Thunb.) Meisn. is typically between 15-25°C (59-77°F). This plant can tolerate a range of temperatures, but extreme temperatures should be avoided. Temperatures below 0°C (32°F) can cause the plant to die if it is exposed for an extended period.
Soil Requirements
This plant can grow in a variety of soils, but it prefers well-drained soils that are rich in organic matter. Soil acidity should be around pH 5-7.5, and the soil should not be waterlogged. Lachnaea nervosa (Thunb.) Meisn. can tolerate moderately fertile soils, but excessive fertilization should be avoided as it can lead to excessive growth and weak stems.
Cultivation Methods
For successful cultivation of Lachnaea nervosa, it's recommended to plant it in well-drained soil with good organic matter content. The plant grows well in partial shade, but it can tolerate full shade or full sun as well. The ideal temperature range for its growth is between 15°C-30°C. Propagation is possible through seeds or cuttings.
Watering Needs
Lachnaea nervosa requires moderate watering, and the soil should be kept slightly moist but not wet. Overwatering causes root rot, whereas underwatering may lead to wilting of the plant. Depending on the weather conditions and soil type, watering frequency may vary, and it's best to check the soil moisture level before watering.
Fertilization
The plant requires regular fertilization during its growth period, which is from spring until autumn. Using a balanced, slow-release fertilizer with equal amounts of nitrogen, phosphorus, and potassium provides the plant with the necessary nutrients. The frequency of feeding can be adjusted based on the plant's growth and overall health, but a general schedule of once per month is sufficient.
Pruning
To maintain the plant's shape and promote growth, pruning can be done in early spring or late autumn. Dead or damaged branches and leaves should be removed regularly, and excessive growth should be cut back to maintain an attractive shape. If left unpruned, the plant may become leggy and weak, which can be detrimental to its overall health.
Propagation of Lachnaea nervosa (Thunb.) Meisn.
Lachnaea nervosa (Thunb.) Meisn. can be propagated through two methods, namely seed propagation and vegetative propagation.
Seed propagation
To propagate Lachnaea nervosa (Thunb.) Meisn. through seeds, collect ripe fruits from the plant during autumn. These fruits should contain seeds that can be sown immediately after collection or cold-stratified for a few weeks to break their dormancy. These seeds can be sown in sandy soil at a depth of 1-2 cm and must be watered regularly until the seeds germinate. The seedlings can be transplanted into individual pots or directly into the ground after they grow to a size of 6-8 cm.
Vegetative propagation
Lachnaea nervosa (Thunb.) Meisn. can be propagated vegetatively through stem cuttings or division during the active growth period. Choose healthy stems with at least two nodes and remove the leaves from the lower nodes. Dip the cut end of the stem into rooting hormone powder and plant it in a well-draining potting mix. Keep the pot in partial shade and maintain the soil moisture until root growth is observed. After 4-6 weeks, the rooted cuttings can be transplanted into individual pots or directly into the ground.
Alternatively, the plant can be divided during spring or autumn by removing the root ball from the soil and separating it into smaller sections. Each section should contain a healthy clump of leaves and roots, and can be replanted immediately into a well-draining soil mix with regular watering until new growth is observed.
Disease Management
Lachnaea nervosa is generally a hardy plant and is not commonly affected by diseases. However, there are some diseases that can affect its growth and development. One of the most common diseases is leaf spot, caused by the fungus Cercospora lachnaeae. This disease causes small brown spots on the leaves which can merge to form larger necrotic areas leading to premature defoliation. To manage this, it is recommended to remove the infected leaves and spray with a fungicide approved for use on the plant.
Another disease that can affect Lachnaea nervosa is powdery mildew caused by Erysiphe cichoracearum. This disease causes white powdery spots on the leaves, which can lead to leaf curling and distortion. To manage this disease, it is recommended to improve air circulation around the plant and reduce humidity as powdery mildew thrives under moist and humid conditions. Fungicides can also be applied to manage this disease, and infected leaves should also be removed and destroyed.
Pest Management
There are also some pests that can affect Lachnaea nervosa, though they are not usually a significant problem. One of the most common pests that can affect this plant is aphids. Aphids suck the sap from the leaves and stems, leading to yellowing, stunted growth, and distorted leaves. To manage this pest, it is recommended to spray the plant with a mixture of soap and water or an insecticide approved for use on the plant.
The other common pest that can affect Lachnaea nervosa is spider mites. These pests are tiny and difficult to detect, and they feed on the underside of leaves causing yellow spots on the leaves. A heavy infestation can lead to leaf drop and stunted growth. To manage this pest, it is recommended to increase air circulation around the plant and to spray the plant with a miticide approved for use on the plant.
