Description
Astragalus pectinatus (Hook.) Dougl. ex G. Don var. platyphyllus M.E. Jones, also known as the big leaf milkvetch, is a perennial herbaceous plant that belongs to the Fabaceae family. It is a highly variable plant, exhibiting substantial morphological and genetic diversity across its range.
Origin
Astragalus pectinatus var. platyphyllus is native to the western United States. Its distribution stretches from California to Wyoming and Colorado, and it can be found growing at elevations ranging from 500 to 3,000 meters.
Common Names
In addition to big leaf milkvetch, Astragalus pectinatus var. platyphyllus is also commonly referred to as the mountain rattleweed, mountain milkvetch, and bigleaf astragalus.
Uses
This plant is valued for its ability to fix nitrogen in the soil, which means it enriches the soil and enhances its fertility. It is also an important component in the diets of grazing livestock and wildlife, providing a valuable source of nutrition. Native American tribes have a long history of using Astragalus pectinatus var. platyphyllus for various medicinal purposes, including treating respiratory problems, reducing inflammation, and improving overall health.
General Appearance
Astragalus pectinatus var. platyphyllus is a perennial herbaceous plant that can grow up to 1 meter in height. It has a broad, fleshy taproot that can reach up to 3 meters in length. The plant has large compound leaves that are pinnately divided into 9 to 21 leaflets and can grow up to 30 cm in length. Its inflorescence consists of dense clusters of pink to purple flowers that bloom from May to August. The fruit is a fuzzy pod that splits open when mature, releasing the seeds within.
Light Requirements
Astragalus pectinatus var. platyphyllus, commonly known as the western prairie clover, requires full sun to grow. It thrives in areas with direct sunlight exposure for at least six hours a day. In areas with intense heat, it can tolerate partial shade during the hottest part of the day. Lack of sunlight can cause leggy growth as well as a decreased amount of flowers.
Temperature Requirements
Astragalus pectinatus var. platyphyllus is a hardy plant that can withstand a wide range of temperature conditions. It typically grows in areas that experience cold winters and hot summers. Generally, it can tolerate temperatures between -25°C and 35°C. However, extreme temperature fluctuations can stress the plant and damage its growth.
Soil Requirements
The western prairie clover prefers well-drained, sandy-loam soils with a pH range of 5.0 to 8.0. It can grow in less fertile soils, but the soil should not be too heavy or compacted. Adequate drainage is vital as it helps prevent root rot. The plant can also tolerate alkaline or slightly saline soils to some extent. It is sensitive to waterlogging and does not perform well in soils with poor drainage.
Cultivation
Astragalus pectinatus var. platyphyllus M.E. Jones is a hardy plant that can tolerate a wide range of temperatures. It grows well in well-draining soil with a pH range of 6.0 to 8.0. It prefers a sunny location with a moderate breeze to prevent fungal disease.
Propagation is usually done from seed or cuttings. Seeds should be sown in spring or early summer, while cuttings should be taken in the early months of spring or autumn. Cuttings should be kept moist until roots form.
Watering Needs
Astragalus pectinatus var. platyphyllus M.E. Jones is drought-tolerant and does not require frequent watering. However, it needs to be watered regularly during its initial growth period. Once established, it requires water only when the soil feels dry to the touch.
Deep watering ensures water reaches the roots. Watering in the morning or evening is ideal because it minimizes evaporation.
Fertilization
Astragalus pectinatus var. platyphyllus M.E. Jones does not require high amounts of fertilizers. Applying balanced fertilizer once a year in early spring before new growth initiates is sufficient.
It is crucial to avoid nitrogen-rich fertilizers as they promote foliage growth but hamper flower and seed production.
Pruning
Astragalus pectinatus var. platyphyllus M.E. Jones does not require pruning, but it can benefit from it. Pruning is usually done in spring when the plant begins to grow actively.
It is recommended to remove dead, damaged, or diseased branches or stems as they hinder healthy growth. Additionally, pruning can promote denser foliage and an attractive shape.
It is crucial to use sterilized pruning tools to prevent the spread of disease.
Propagation of Astragalus pectinatus (Hook.) Dougl. ex G. Don var. platyphyllus M.E. Jones
Astragalus pectinatus (Hook.) Dougl. ex G. Don var. platyphyllus M.E. Jones is a perennial plant that is commonly propagated through both seed and vegetative methods.
Seed Propagation
Seed propagation is the most common method of propagating Astragalus pectinatus (Hook.) Dougl. ex G. Don var. platyphyllus M.E. Jones. Seeds should be collected from the plant in the fall. The seeds should then be dried and stored in a cool, dry place until they are ready to be planted. Seeds can be planted in the spring, after the danger of frost has passed.
To prepare for planting, the seeds should be stratified by storing them in moist sand or vermiculite in the refrigerator for several weeks. Once stratified, the seeds can be planted in a well-draining soil mix. The seeds should be lightly covered with soil and kept moist until they germinate.
Vegetative Propagation
Astragalus pectinatus (Hook.) Dougl. ex G. Don var. platyphyllus M.E. Jones can also be propagated through vegetative methods, such as cuttings or division.
Cuttings should be taken in the spring, from new growth that has not yet hardened. The cuttings should be approximately 6 inches long and should be planted in a well-draining soil mix. The cuttings should be kept moist and out of direct sunlight until they root.
Division can be done in the spring or fall, by digging up the mature plant and dividing the root system. Each division should have several viable shoots and a healthy root system. The divisions can then be planted in a well-draining soil mix.
Disease Management
Astragalus pectinatus var. platyphyllus is generally a hardy plant, but it is still susceptible to some diseases.
One common disease that affects this plant is root rot, which can be caused by various soil-borne fungi. To manage root rot, it is important to ensure that the soil is well-draining and that the plant is not overwatered. If root rot is already present, affected plants should be removed and destroyed to prevent the spread of the disease.
Another disease that may affect Astragalus pectinatus var. platyphyllus is powdery mildew, which is caused by a fungal infection. This disease can be managed by removing infected parts of the plant and treating the remaining plant with a fungicidal spray. It is also important to provide good air circulation around the plant to prevent future infections.
Pest Management
Astragalus pectinatus var. platyphyllus may also be targeted by certain insect pests.
One common pest is the spider mite, which can cause significant damage by feeding on the plant's leaves. To manage spider mites, insecticidal soaps or oils can be used to suffocate and kill the pests. Additionally, introducing predatory mites (such as Phytoseiulus persimilis) can help to control spider mite populations.
Another pest that may affect this plant is the aphid, which also feeds on the leaves and can cause stunted growth. Aphids can be managed by introducing natural predators, such as ladybugs, or by using insecticidal sprays.
Overall, managing diseases and pests for Astragalus pectinatus var. platyphyllus involves careful monitoring and timely interventions to prevent the spread of damage. By taking proactive measures, it is possible to maintain healthy plants and prevent the loss of yield.
