Swertia lassenica St. John
Swertia lassenica St. John, also known as Lassen swertia, is a flowering plant species that belongs to the gentian family (Gentianaceae). It is native to the Sierra Nevada and Cascade Range, specifically to the Lassen Volcanic National Park in California, USA.
Common Names
The plant is commonly known as Lassen swertia, Lassen Mountain swertia, Lassen Centaury, or Lassen gentian.
Appearance
Swertia lassenica St. John typically grows up to 30 cm tall and features a basal rosette of leaves and green stems with narrow leaves that are arranged opposite or in whorls. The plant produces greenish-yellow flowers that bloom from July to September. The flowers have five petals fused at the base and a green calyx with five lobes. The plant's roots are thick and fleshy, and it grows in moist areas such as meadows and streambanks.
Uses
The plant is used by the Maidu tribe for various medicinal purposes, including the treatment of colds, headaches, and stomach aches. It is also used as a digestive aid, and poultices made from the leaves and roots have been used to heal wounds and burns. The plant's roots are also harvested and consumed as a food source by the Maidu people.
Swertia lassenica St. John is also a popular ornamental plant for rock gardens and meadows restoration projects due to its attractive flowers and its ability to attract pollinators like bees and butterflies.
Light Requirements
Swertia lassenica St. John is a plant that prefers partial shade to full sun exposure. It thrives in an environment with bright, indirect sunlight and should not be exposed to direct sunlight for prolonged periods.
Temperature Requirements
This plant grows well in cooler environments and prefers temperatures between 5°C and 23°C. It can tolerate lower temperatures of up to -5°C, but very high temperatures may cause the plant to wilt and even die.
Soil Requirements
The Swertia lassenica St. John plant requires well-drained soils that are rich in organic matter. It grows best in slightly acidic to neutral soils with a pH range between 5.5 and 7.0. This plant is tolerant of many soil types but does not like clay soils that retain too much water as it may cause root rot and poor growth.
Water Requirements
Swertia lassenica St. John requires moderate watering without letting the soil become too dry or waterlogged. Water the plant when the soil surface is dry to the touch. Be sure to allow the soil to drain well to prevent the roots from rotting.
Fertilizer Requirements
Fertilize the Swertia lassenica St. John plant regularly with a balanced fertilizer with a ratio of N-P-K of 10-10-10 or 20-20-20. Apply the fertilizer once every month, during the growing season of spring and summer. Avoid over-fertilizing the plant as this may damage the plant by burning the roots.
Cultivation methods
Swertia lassenica St. John can grow in areas with partial to full sun exposure, making it a versatile choice for planting. The plant prefers well-drained soil and can be propagated by seeds or cuttings. When planting, ensure that the soil is rich in organic matter, and space the seedlings or cuttings 6 to 10 inches apart depending on the desired density of the planting.
Watering needs
Swertia lassenica St. John requires regular watering, especially during its growing season. However, avoid overwatering, which can lead to root rot and other fungal infections. Instead, water the soil around the plant's base, ensuring that the soil remains moist but not waterlogged. Monitor the soil moisture regularly and adjust the frequency and amount of watering based on weather conditions and the plant's needs.
Fertilization
Swertia lassenica St. John benefits from periodic fertilization to encourage healthy growth and flowering. Use a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium, such as a 10-10-10 or 12-12-12 fertilizer. Apply the fertilizer every four to six weeks during the growing season, following the instructions on the package regarding dosage and application method. Avoid over-fertilization, which can burn the plant's roots and foliage.
Pruning
Swertia lassenica St. John does not require extensive pruning but can benefit from periodic removal of dead or yellowing leaves and branches. Use clean, sharp pruning shears to make clean cuts and avoid damaging the plant's healthy foliage and stems. Avoid pruning the plant during its flowering season, as this can reduce the number of blooms and impact the plant's overall appearance.
Propagation of Swertia lassenica St. John
Swertia lassenica St. John is a lovely, low-growing plant that is endemic to North America. The plant produces attractive, bright yellow-green leaves and small, star-shaped flowers that bloom in summer. If you're interested in growing Swertia lassenica St. John in your garden, you can propagate it by seed or by division.
Propagation by Seed
If you want to propagate Swertia lassenica St. John by seed, the best time to sow the seeds is in late winter or early spring. You can start the seeds indoors in seed trays or sow them directly in the garden bed. The seeds are quite small, so you should cover them lightly with soil. Water regularly, keeping the soil moist but not soggy, until the seedlings emerge. Once they do, transplant them to their permanent place in the garden.
Propagation by Division
If you already have a mature Swertia lassenica St. John plant, you can propagate it by division. The best time to divide the plant is in early spring or late summer. To divide the plant, carefully lift it from the ground and gently separate the roots into two or more portions. Replant each portion in a new area of the garden, making sure to water regularly until the plant becomes established.
Disease Management
Swertia lassenica St. John is prone to fungal diseases, such as rust and powdery mildew. In order to prevent rust, it is important to avoid watering the leaves of the plant, as moisture can lead to the growth and spread of the fungus. Powdery mildew can be prevented by avoiding high humidity levels, and by providing proper air circulation through regular pruning and spacing of plants.
If a fungal disease is already present, it may be treated with a fungicide. However, it is important to read and follow the instructions provided with the specific product, as different fungicides may have different application rates and methods, and some may be harmful to the plant or the environment.
Pest Management
Swertia lassenica St. John is typically resistant to most pests. However, aphids and spider mites may occasionally infest the plant. These pests can be controlled by spraying the plant with a strong stream of water, or by applying an insecticidal soap or oil. It is important to avoid using broad-spectrum insecticides, as these may harm beneficial insects such as bees and butterflies.
In addition, it is recommended to prune and discard any infected or damaged plant parts, as they may attract pests or harbor diseases.
