Description
Astragalus decumbens (Nutt. ex Torr. & Gray) Gray var. crispatus (M.E. Jones) Cronq. & Barneby is a herbaceous plant native to the western United States. It belongs to the Fabaceae family, which is known for its members' beneficial effects on soil health and fertility. The species' subspecific epithet 'crispatus' means 'sharply curled,' in reference to the plant's hairy leaves which often curl inwards.
Common names
The plant is commonly known as "sharp-leaf milkvetch" or "curled milkvetch."
Uses
Astragalus decumbens var. crispatus is a valued species in revegetation and restoration projects, particularly in areas with disturbed soil. The plant's deep roots help stabilize soil, while its presence improves soil quality by fixing nitrogen. Native American tribes also recognized its medicinal properties and used different parts of the plant to treat ailments such as heartburn and coughs.
General appearance
Astragalus decumbens var. crispatus is a low-growing perennial plant that forms mats up to 1 foot in diameter. Its stems and leaves are covered in silky white hairs, giving it a soft appearance. The leaves are pinnately compound, with 6 to 12 pairs of small leaflets. The plant blooms from May to August, producing small purple flowers that form in tight clusters at the tips of the stems. The fruit is a small pod containing seeds that are dispersed when the pod splits open.
Growth Conditions for Astragalus decumbens var. crispatus
Astragalus decumbens var. crispatus is a low-growing perennial plant that is usually found in mixed-grass prairies, oak woodlands, and slopes. The plant has a well-developed root system that helps it to adapt to a variety of soil types and growing conditions.
Light Requirements
Astragalus decumbens var. crispatus prefers full sun to partial shade. It can tolerate some shade, but prolonged periods of shade can hinder its growth and delay flowering.
Temperature
This plant prefers mild temperatures and experiences growth in the spring and summer months. It can be found in USDA hardiness zones 4 to 9, where temperatures can range from -30°F to 20°F in winter.
Soil Requirements
The plant prefers well-drained soils that are sandy, loamy, or clayey, with a pH range of 6.1 to 7.9. It can also tolerate soils that are slightly acidic or slightly alkaline. It is important to note that the plant may not tolerate soils that are consistently wet or have poor drainage.
It can grow in soils that are low in fertility and have a low organic matter content. However, adding some organic matter to the soil can improve its growth and flowering. Moderate moisture is required for growth.
Astragalus decumbens var. crispatus has a low water requirement, and well-established plants can survive prolonged periods of drought.
In summary, Astragalus decumbens var. crispatus is an adaptable plant that grows well in a variety of soil types, from sandy to loamy to clayey. It prefers full sun to partial shade and mild temperatures, and moderate levels of moisture. Properly taking care of it will help provide an attractive landscape feature.
Cultivation Methods
Astragalus decumbens (Nutt. ex Torr. & Gray) Gray var. crispatus (M.E. Jones) Cronq. & Barneby is a hardy plant that thrives in dry, sandy soils and rocky hillsides. It can grow up to 30 cm tall with a spread of about 60 cm. This plant is suitable for use in xeriscaping as it is drought tolerant and can withstand extreme temperatures.
The plant can be propagated by seed or cuttings. Seeds should be planted in the winter or early spring in well-drained soil while cuttings can be taken in spring or summer and rooted in moist sand or vermiculite.
Watering Needs
Astragalus decumbens (Nutt. ex Torr. & Gray) Gray var. crispatus (M.E. Jones) Cronq. & Barneby is a drought-tolerant plant that does not require regular watering. During the first year after planting, the plant should be watered regularly until it becomes established. Afterward, it should only be watered during extended drought periods.
Overwatering this plant can lead to root rot and other diseases. It is best to water the plant deeply but infrequently.
Fertilization
Astragalus decumbens (Nutt. ex Torr. & Gray) Gray var. crispatus (M.E. Jones) Cronq. & Barneby is a nitrogen-fixing plant that does not require much fertilizer. However, a light application of a balanced fertilizer in early spring can help promote growth and flowering.
It is essential to avoid using fertilizers that are high in nitrogen as this can lead to excessive vegetative growth at the expense of flower production.
Pruning
Astragalus decumbens (Nutt. ex Torr. & Gray) Gray var. crispatus (M.E. Jones) Cronq. & Barneby does not require regular pruning. However, to promote bushiness and control the plant's shape, pruning can be done after flowering in late spring or early summer.
It is best to remove only a third of the plant at a time to avoid stressing it. Deadheading can also be done to remove spent flowers and promote more blooms.
Propagation of Astragalus decumbens var. crispatus
Astragalus decumbens var. crispatus is propagated both through seeds and vegetative methods such as division and cuttings. The propagation method mostly depends on the purpose of propagating the plant.
Propagation through Seeds
Propagation through seeds is the most common and easy method of propagating Astragalus decumbens var. crispatus. The seeds should be sown in well-drained soil mix in early spring when the soil temperature reaches at least 15°C. The seedlings will appear in two to three weeks and should be kept in a warm and well-lit area with moderate watering. It is advisable to use fresh seeds for propagation for the best results.
Propagation through Division
Propagation through division is another method of propagating Astragalus decumbens var. crispatus. It involves removing an established plant from the ground or container and dividing it into smaller clumps. Each clump should have roots attached to them. The smaller plants should be planted in a well-drained soil mix and kept in a warm and well-lit place with moderate watering. Division is mostly done during the spring or fall when the plant is not actively growing.
Propagation through Cuttings
Propagation through cuttings is also possible for Astragalus decumbens var. crispatus. It involves taking a stem cutting from an established plant and planting it in a well-drained soil mix. The cutting should be about 5 to 7 cm in length and stripped of most of its leaves. The cutting should be planted in a well-lit and warm area and kept moist. The cuttings are usually taken in early summer for the best results.
Disease Management
One of the common diseases that affect Astragalus decumbens var. crispatus is root rot, which is caused by fungi in the soil and can lead to wilting, yellowing, and death. To manage this, avoid overwatering and ensure proper drainage. Plant in well-draining soil and avoid planting in areas prone to flooding. Consider using a fungicide if the disease is severe.
Another disease that can affect this plant is powdery mildew, a fungal infection that appears as a white powdery substance on the leaves. This disease can cause stunted growth and ultimately reduce yield. To manage this, remove infected leaves and reduce humidity by providing adequate spacing and avoiding overcrowding. Additionally, spraying with a fungicide may be necessary.
Pest Management
One of the common pests that can affect Astragalus decumbens var. crispatus is the aphid, which feeds on the plant sap and can cause deformation, stunted growth, and ultimately reduce yield. To manage this, insecticidal soap or neem oil can be used to control the infestation. Additionally, companion planting with plants that attract natural predators of aphids can be helpful.
Another pest that can affect this plant is the spider mite, which sucks plant sap and cause yellowing and leaf drop. To manage this, spraying with insecticidal soap or neem oil can be effective. Increasing humidity and providing proper air circulation can also prevent spider mite infestation. Additionally, introducing natural predators of spider mites such as ladybugs can be helpful.
