Origin
Astragalus bisulcatus (Hook.) A.Gray, also known as two-grooved milkvetch, is a perennial plant species native to North America, specifically the western United States and parts of Canada. It can be found in dry meadows, rocky slopes, and open woodlands at elevations ranging from 2,500 to 9,000 feet.
Common Names
Aside from two-grooved milkvetch, Astragalus bisulcatus is also commonly referred to as twin-grooved milkvetch, two-groove milkvetch, and double-keeled milkvetch.
Uses
Astragalus bisulcatus has a variety of uses, both medicinal and non-medicinal. Historically, Native Americans have used this plant as a source of food and medicine. The entire plant is edible, and can be cooked like a vegetable or used as a seasoning, while the roots were used in traditional medicine for a variety of ailments, such as wounds and coughs.
Modern research has also shown that Astragalus bisulcatus may have potential therapeutic benefits due to its high flavonoid content, specifically in the areas of cancer treatment and immune system regulation.
This plant is also significant in ecological restoration efforts, as it has the ability to fix nitrogen in the soil, helping to improve soil quality and support other plant species.
General Appearance
Astragalus bisulcatus is a herbaceous perennial plant that grows up to two feet tall. It has a deep, extensive taproot and multiple stems that can be either erect or spreading. The leaves are pinnately compound, with 9-19 leaflets that are oblong to elliptic in shape. The plant produces numerous small, white to light purple flowers that are arranged in long, narrow clusters. The fruit is a hairy, pod-like structure that contains seeds.
Light Requirements
Astragalus bisulcatus is a sun-loving plant that thrives in full sunlight. It requires at least 6 hours of direct sunlight per day to grow well. It can also tolerate partial shade, but the plant becomes leggy if it doesn't receive enough sunlight. It is recommended to plant it in a location that receives full sun exposure for best growth results.
Temperature Requirements
Astragalus bisulcatus is a hardy perennial plant that can tolerate a wide range of temperatures. It is adapted to arid environments and can tolerate both extreme heat and cold temperatures. The ideal temperature range for this plant is between 60°F and 95°F. In areas where temperatures drop below 50°F, it is recommended to grow the plant in a greenhouse or indoors during the winter months. It can tolerate drought conditions but does better with occasional watering.
Soil Requirements
Astragalus bisulcatus prefers loose, well-draining soil that is slightly acidic to neutral with a pH range of 6.0 to 7.5. The plant can tolerate poor soil quality but thrives in fertile, well-draining soils. The soil should be rich in organic matter to improve water-holding capacity and soil texture. The plant can tolerate soil salinity up to a certain level, making it an excellent option for dry, arid environments with high salinity levels. It is important to avoid planting the plant in soils with poor drainage to prevent root rot and other diseases.
Cultivation Methods
Astragalus bisulcatus (Hook.) A.Gray is a plant that is easy to cultivate and can thrive in a variety of soil types. It prefers well-drained soils that are slightly alkaline with a pH of 7.5 to 8.5. The plant should be grown in a sunny location, but it can tolerate partial shade as well. The best time to plant is during the spring in a location with moderate temperatures.
Watering Needs
The Astragalus bisulcatus (Hook.) A.Gray plant requires regular watering, especially during its growing season. The plant should be watered deeply but infrequently to prevent the soil from becoming waterlogged. It is important to avoid getting water on the leaves, as the plant is susceptible to fungal diseases. The frequency of watering should be decreased during the fall and winter.
Fertilization
Astragalus bisulcatus (Hook.) A.Gray should be fertilized twice a year, once in the spring and once in the fall. The best fertilizer to use is a balanced 10-10-10 fertilizer. The fertilizer should be applied according to the instructions on the package. Over-fertilization should be avoided, as too much fertilizer can burn the roots and damage the plant.
Pruning
Pruning Astragalus bisulcatus (Hook.) A.Gray is not necessary, as the plant has a natural shape and will grow well without pruning. However, if necessary, pruning can be done to remove dead or damaged branches or to shape the plant. The best time to prune is during the fall or winter when the plant is dormant. Pruning during the growing season should be avoided, as this can damage the plant and reduce its growth.
Propagation of Astragalus bisulcatus
Astragalus bisulcatus (Hook.) A.Gray can be propagated through sexual and asexual means.
Sexual propagation
Seeds are the most common way to propagate Astragalus bisulcatus sexually. The plants are monoecious, meaning they contain both male and female reproductive organs. The flowers of Astragalus bisulcatus are hermaphroditic, meaning they contain both male and female reproductive parts in the same flower.
After fertilization occurs, the seedpods will turn brown and dry out. The seedpods should be collected before they burst open to release the seeds. Once collected, the seeds should be sown in well-draining soil in a sunny location.
Asexual propagation
Astragalus bisulcatus can also be propagated asexually through stem cuttings, layering or dividing the root ball.
To propagate through stem cuttings, take a 4-6 inch cutting from a healthy plant in the spring or early summer. Dip the cutting in rooting hormone and plant it in a well-draining soil mix. Keep the soil moist and in a warm, sunny location until roots develop.
Layering is another way to propagate A. bisulcatus asexually. To do this, find a low-growing branch and scrape the bark on the bottom section. Bury the scraped section in soil, keeping the top of the branch exposed. After roots develop, cut the new plant off of the parent plant and transplant to a sunny location.
Finally, A. bisulcatus can be propagated through root division. This method works best in the fall or early spring when the plant is dormant. Dig up the root ball and use a sharp knife to cut the roots into sections. Replant the sections in well-draining soil and water thoroughly.
Disease Management
Astragalus bisulcatus is susceptible to various foliage and root diseases. The common diseases affecting the plant include powdery mildew, brown spot, and root rot. Powdery mildew is common in dry and humid conditions, and it causes white dusty spots on leaves and stems, which later turn yellow and die. Brown spot, on the other hand, causes brownish/black spots on leaves and stems. It leads to the death of the infected parts if left uncontrolled. Root rot, caused by pathogens like Pythium and Phytophthora, attacks the roots and reduces the plant's ability to uptake water and nutrients, leading to wilting and death.
To manage these diseases, it is essential to practice proper crop sanitation, including the removal and destruction of all infected parts, proper crop rotation, and proper plant spacing. The application of chemical fungicides may also be necessary in severe cases, but it should be done following the recommended guidelines to minimize plant damage.
Pest Management
In addition to diseases, Astragalus bisulcatus is also susceptible to insect pests like aphids, spider mites, and cutworms. Aphids suck the sap from the leaves and stems, causing curling and distortion of the leaves. Spider mites, on the other hand, feed on the plant's sap, causing the leaves to turn yellow. Cutworms, which are larvae of nocturnal moths, feed on the plant's stems and roots, leading to wilting and death.
To manage these pests, it is essential to monitor the plants regularly and take early control measures. The use of insecticidal soap and neem oil is effective in controlling aphids and spider mites. Additionally, the application of Bacillus thuringiensis (Bt) may be necessary to manage cutworms. Cultural practices such as crop rotation, proper plant spacing, and weed control also help to minimize pest infestations.
