Origin
Astragalus nuttallianus DC. is a species of flowering plant in the family Fabaceae. It is native to the western United States, including California, Nevada, Utah, and Wyoming.
Common Names
The plant is commonly known as Nuttall's milkvetch, Nuttall's astragalus, or longspur milkvetch.
Uses
Astragalus nuttallianus DC. has traditional medicinal uses among various Native American tribes including the Gosiute, Paiute, and Shoshone. The roots of the plant were used as a traditional remedy for a variety of ailments such as upset stomach and fever.
It is also used in the restoration of degraded lands due to its ability to fix nitrogen in the soil, enhancing soil fertility and promoting new plant growth.
General Appearance
Astragalus nuttallianus DC. typically grows as a perennial herb, with a woody base and stems that can reach up to 1 meter in height. The leaves are typically pinnate and comprised of 8-20 leaflets that are lanceolate in shape.
The flowers are typically purple or lavender and bloom in the months of May through August. The fruit produced by the plant is a pod that contains seeds.
Light Requirements
Astragalus nuttallianus DC. requires full sun to grow well. It can tolerate partial shade but may not flower as much in shaded areas. It is best to plant this species in an area that receives at least 6 hours of direct sunlight per day.
Temperature Requirements
The ideal temperature range for Astragalus nuttallianus DC. is between 60-80°F (15-27°C). It can tolerate temperatures up to 90°F (32°C) but may not grow as well in extreme heat. This species is winter hardy in USDA zones 4-8 and can withstand temperatures as low as -30°F (-34°C).
Soil Requirements
Astragalus nuttallianus DC. grows well in well-draining soils that are slightly acidic to neutral (pH 6.0-7.0). It can tolerate poor soils but will not grow as vigorously as it would in rich, fertile soils. Adding organic matter such as compost or aged manure can improve soil fertility and water-holding capacity. This species prefers soils that are not waterlogged and can withstand periods of drought once established.
Cultivation Methods for Astragalus nuttallianus DC.
Astragalus nuttallianus DC. is suited to an open location that receives at least six hours of sun every day. The ground must be well-drained and enriched with humus. You can cultivate a new plant from seeds, root cuttings or plants purchased from a nursery. Spring is the best time to sow seeds in colder areas, whereas in warm climates, fall is ideal. The seeds need 30 to 60 days of cold stratification to break their dormancy.
Watering Needs for Astragalus nuttallianus DC.
The plant prefers to grow in dry soil, so it can survive periods of drought. Young plants need to be watered regularly to allow the roots to establish well in the soil. Once the plant reaches maturity, it does not need much watering. Watering is necessary only during long droughts or extended heatwaves.
Fertilization for Astragalus nuttallianus DC.
Since Astragalus nuttallianus DC. is a plant that grows in low-nutrient soil, it does not need much fertilization. It is better to fertilize once or twice a year with a balanced slow-release fertilizer in small amounts.
Pruning of Astragalus nuttallianus DC.
Pruning is not necessary for this plant as it grows naturally to its desired size. You can remove dead or diseased wood if there are any. However, excessive pruning may cause the plant to decline in vigor.
Propagation of Astragalus nuttallianus DC.
Astragalus nuttallianus DC., or Nuttall's milkvetch, is primarily propagated through seed. However, it can also be propagated through vegetative means such as cuttings or division.
Seed Propagation
The most common method of propagation for Astragalus nuttallianus is through seed. Seeds should be sown in the fall for natural stratification or they can be artificially stratified indoors. Germination can occur in 2-3 weeks. Seeds should be sown in well-draining soil and kept moist but not waterlogged.
Vegetative Propagation
Astragalus nuttallianus can also be propagated through vegetative means. Stem cuttings should be taken in the summer when the plant is actively growing. The cuttings should be dipped in rooting hormone and placed in a well-draining soil mix kept moist but not waterlogged. Roots can develop in as little as 3-4 weeks.
Division of the plant can also be done in the spring or fall. This involves digging up the plant and separating the roots into smaller sections. These sections can then be replanted in well-draining soil and should be kept moist but not waterlogged until new growth appears.
Disease Management
Astragalus nuttallianus DC., commonly known as Nuttall's milkvetch, can be affected by several diseases. One of the most common ones is powdery mildew, which is a fungal disease that produces a white or gray powdery coating on the leaves and stems of the plant. To manage this disease, it is recommended to remove and dispose of the infected plant parts and ensure proper air circulation around the plant to prevent moisture buildup. In severe cases, fungicides may be necessary.
Another disease that can affect Astragalus nuttallianus is root rot, which is caused by several fungal pathogens. Symptoms include yellowing and wilting of leaves and stunted growth. To manage this disease, avoid overwatering the plant and ensure proper drainage. In severe cases, removing and disposing of the infected plant may be necessary.
Pest Management
Astragalus nuttallianus can also be affected by several pests. One common pest is the aphid, which are small, soft-bodied insects that feed on the plant sap and can lead to distorted growth and yellowing leaves. To manage this pest, a strong stream of water can be used to wash them off the plant, and insecticidal soaps can be used to control severe infestations.
The plant can also be affected by spider mites, which are tiny insects that suck the sap from the leaves and cause them to turn yellow or brown. To manage this pest, regularly spraying the plant with water and insecticidal soap can be effective.
In conclusion, Astragalus nuttallianus can be affected by various diseases and pests, but proper management techniques such as removing infected plant parts, ensuring proper air circulation, and using insecticidal soaps can help prevent and control them.
