Origin
Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn is a plant species that belongs to the legume family. It is native to North America, specifically in the western part of the continent including the states of Montana, Utah, Colorado, Wyoming, and New Mexico.
Common Names
The plant is commonly known as Divaricate Thermopsis, Rocky Mountain Thermopsis, and Mountain Golden Banner. It can also be referred to as Devil’s shoestring, though this name is typically used for a similar species, Thermopsis rhombifolia.
Uses
Thermopsis montana Nutt. var. divaricarpa is primarily used for ornamental purposes due to its attractive yellow flowers. It is also known to have medicinal properties. Native American tribes have used it to treat various ailments such as respiratory problems, stomach aches, and fever. The plant also contains a toxic alkaloid, cytisine, which has potential as a smoking cessation agent.
General Appearance
The plant typically grows up to 3 feet tall and has a bushy and spreading habit. The leaves are pinnate, 2-5 inches long, and composed of several leaflets. It produces bright yellow flowers that bloom in late spring and early summer. The flowers are arranged in dense clusters and are followed by legume-like seed pods. The plant prefers full sun and well-drained soils, and can be found growing in meadows, grasslands, and open woods in its native range.
Light Requirements:
Thermopsis montana Nutt. var. divaricarpa grows well under full sun or partial shade. However, it thrives best under full sunlight exposure in areas where the intensity of the sun is not too high.
Temperature Requirements:
The plant is tolerant of a wide range of temperatures. It grows naturally in the mountainous regions of Western North America, where the temperature typically varies from cool to cold. During the growing season, it prefers a temperature range of between 15°C and 23°C (59°F to 73°F). It can tolerate light frost in the fall and spring, but the roots require protection during the winter.
Soil Requirements:
The plant prefers well-drained soils that are slightly acidic to neutral. It can tolerate a wide variety of soils, including loams, clays, and sandy soils. However, they can grow best in well-draining soils that are rich in organic matter. The ideal soil pH range for Thermopsis montana Nutt. var. divaricarpa is between 6.0 and 7.2.
Cultivation Methods
Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn is a hardy perennial that thrives in well-drained soil and full sun. It can tolerate a wide range of soil types, including sand, loam, and clay. The plant prefers a neutral to slightly acidic soil, with a pH between 6.6 and 7.5. It is essential to plant the seeds in the early spring, at least two weeks before the last expected frost, and keep the soil moist until germination. The plant will grow up to two feet tall and one and a half feet wide, so make sure to space the plants at least two feet apart.
Watering Needs
Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn prefers to grow in moist soil, but overwatering can lead to root rot. It is essential to water the plant deeply once a week, especially during dry spells, and let the soil dry out slightly between watering. If the leaves start to wilt or turn yellow, it may be a sign of underwatering. On the other hand, if the leaves start to droop and turn brown, it might be a sign that you are overwatering the plant.
Fertilization
Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn does not require a lot of fertilizer, but it can benefit from a balanced fertilizer application in the spring. Use a slow-release fertilizer with an N-P-K ratio of 10-10-10 or 12-12-12 and apply it according to the label directions. Avoid applying fertilizer near the base of the stem, as it can burn the roots and cause damage to the plant.
Pruning
Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn does not require much pruning, but it can benefit from deadheading to promote continuous blooming. Use clean, sharp pruning shears and cut the spent flowers just below the base. Deadheading can also prevent the plant from self-seeding and spreading too aggressively. If you need to control the plant's size or shape, you can also trim the stems back by up to one-third of their total length after blooming. Avoid pruning the plant in the fall, as this can stimulate new growth that may be damaged by frost.
Propagation of Thermopsis montana Nutt. var. divaricarpa
There are several methods for propagating Thermopsis montana Nutt. var. divaricarpa, including seed propagation, division, and cuttings.
Seed Propagation
Seed propagation is the most common method for multiplying Thermopsis montana Nutt. var. divaricarpa. Seeds can be sown directly in the ground in the fall or spring, or indoors in pots during the winter. The seeds should be sown about 1/4 inch deep and spaced about 6 to 8 inches apart. Germination can take up to three weeks, depending on the conditions. Once the seedlings have emerged, they should be thinned to one every 12 inches.
Division
Division is another method for propagating Thermopsis montana Nutt. var. divaricarpa. This is typically done in the spring or fall when the plant is dormant. The plant's roots should be carefully dug up and divided into smaller sections, each with a healthy stem and root system. The sections can be replanted in their new location and watered well.
Cuttings
Cuttings can also be taken for propagation of Thermopsis montana Nutt. var. divaricarpa. This is typically done in the early summer when the plant is actively growing. Cuttings should be taken from the softer, newer growth and should include a node or two. The cuttings should be about 4 to 6 inches in length. The cuttings can be planted directly in the ground or in pots. It is important to keep the soil moist until roots have formed.
Disease and Pest Management for Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn
Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn is generally a hardy plant but can be affected by certain pests and diseases. It is essential to take preventive measures to ensure the good health of the plant.
Common Diseases and Their Management
Fungal Leaf Spots: The plant may get affected by fungal pathogens, causing leaf spots. The ideal conditions for the growth of pathogens are high humidity and warm temperatures. The affected leaves show dark-colored spots and yellowing, leading to defoliation. To prevent the occurrence of the disease, it is essential to maintain proper spacing between the plants and avoid overhead irrigation. The affected plant parts must be pruned, and the debris should not be left in the field. A weekly spray of fungicides like copper-based products can also help in controlling the disease.
Root Rot: This disease is caused by soil-borne pathogens that attack the roots of the plant. The typical symptoms include wilting, yellowing, and ultimately death. To prevent the occurrence of the disease, one must ensure that the soil has proper drainage and aeration, and the plant is not overwatered. The use of well-drained soil mixed with organic matter can also help in controlling the disease. Fungicides can be applied for treating the affected plants, but prevention is still the best approach.
Common Pests and Their Management
Aphids: Aphids suck the sap from the new shoots of the plant, causing stunted growth and yellowing of leaves. They also excrete honeydew which leads to the growth of sooty mold on the plant. Natural predators like ladybugs and lacewings can help in controlling the aphid population. Regular hose spraying with a mild detergent solution can also help in reducing the infestation. In severe cases, application of insecticides may be required.
Thrips: Thrips cause distorted and browned leaves that curl around the edges. They are found in clusters on the leaves and stems. The application of neem oil and insecticidal soap can help in controlling the infestation. Regular pruning of the affected plant parts and cleaning of debris can also prevent the infestation.
Cutworms: Cutworms feed on the young seedlings and cut the stem below the soil level, leading to death. Wrapping the stem with aluminum foil or plastic collars can prevent the cutworms' entry. Bacillus thuringiensis-based insecticides can also help in controlling the population.
In conclusion, taking preventive measures and practicing integrated pest management (IPM) can help in maintaining the good health of the Thermopsis montana Nutt. var. divaricarpa (A. Nels.) Dorn plant.
