Origin
Astragalus cusickii Gray var. sterilis (Barneby) Barneby is a plant species that is native to North America, specifically to the western regions of the United States and Canada. It typically grows in dry, rocky areas such as canyons, mesas, and slopes. The plant belongs to the Fabaceae (bean family) and was first described by American botanist, Rupert C. Barneby in 1977.
Common Names
The plant has several common names including Sterile Milkvetch, Barneby's Milk-vetch, Cusick's Milk-vetch, and Cusick's Groundplum.
Uses
Like many members of the Astragalus genus, Astragalus cusickii Gray var. sterilis has a variety of medicinal uses. Native Americans traditionally used the plant to treat a variety of ailments such as fever, sore throats, and respiratory infections. The root of the plant is said to have immune-boosting properties and research has shown that it may have potential applications in cancer treatment.
The plant also has ecological value as it is an important food source for livestock and wildlife. Its taproot can fix atmospheric nitrogen, contributing to soil fertility, and its foliage provides cover and shelter for insects and other small animals.
General Appearance
Astragalus cusickii Gray var. sterilis is a herbaceous, perennial plant that typically grows up to 40 cm in height. Its stems are slender and covered in fine, silky hairs. The leaves are pinnately compound, with 8-14 leaflets that are oval-shaped and measure up to 1 cm in length. The plant produces flowers from May to July in the form of small, purple or violet, pea-like blossoms. The flowers are arranged in small clusters on the stem. The fruit is a small, smooth, round pod that contains several seeds.
Light Requirements
Astragalus cusickii Gray var. sterilis (Barneby) Barneby is an extremely resilient plant with low to moderate demands in terms of light. It can tolerate both direct and partial sunlight. However, it is essential to note that direct sunlight exposure can lead to excessive heat that can harm the plant. Therefore, it is best to keep the plant under partial sunlight for optimal growth.
Soil Requirements
The typical growth conditions for Astragalus cusickii Gray var. sterilis (Barneby) Barneby call for well-draining soil that has excellent aeration and water retention. The plant prefers a slightly alkaline to neutral soil pH of 7.0 to 8.0. The soil should also be nutrient-rich to facilitate optimal plant growth. A mixture of loam soil, sand, and gravel in equal proportions, with added compost or manure, can be ideal for the plant.
Water Requirements
Astragalus cusickii Gray var. sterilis (Barneby) Barneby has moderate water requirements. It thrives in moist soil that is not waterlogged or soggy. Overwatering can lead to stress, rotting, and death of the plant. Therefore, it is essential to keep the soil well-draining and avoid waterlogging. Regular watering, mainly during the growth season, can support the plant's optimal growth.
Temperature Requirements
Astragalus cusickii Gray var. sterilis (Barneby) Barneby thrives in a variety of temperature conditions. The plant prefers a warm and dry environment. Temperatures between 15°C and 30°C are suitable for optimal growth. Therefore, the plant can thrive in areas with hot summers and cold, dry winters. However, extreme cold or hot temperatures can cause damage to this plant. Therefore, it is essential to keep the plant in a greenhouse or indoors in extreme weather conditions.
Cultivation
Astragalus cusickii Gray var. sterilis (Barneby) Barneby, is an evergreen perennial shrub that requires low to medium maintenance. It is native to North America's mountainous regions and prefers well-draining soil and full sun exposure for at least six hours a day. The plant can be propagated through seed, root cuttings, or new shoots. It is essential to maintain a warm soil temperature of 60-70°F (15-21°C) to promote seed germination.
Watering Needs
Astragalus cusickii Gray var. sterilis (Barneby) Barneby requires moderate watering during the summer season. It is essential to keep the soil moist, but not waterlogged. Overwatering can lead to root rot, affecting the plant's health significantly. Stick to watering the plant once a week during average temperatures and twice a week during hot weather conditions. It would be best to use a watering can over a hose since it allows for better control over the amount of water you use.
Fertilization
Astragalus cusickii Gray var. sterilis (Barneby) Barneby is a moderate feeder and requires fertilization to boost its growth and flower production. Feed the shrub using a general-purpose fertilizer in the spring and summer seasons. You can use a slow-release fertilizer to minimize the shock of overfeeding. Be careful not to over-fertilize since it can lead to excessive foliage growth, limiting the number of blossoms produced.
Pruning
Pruning is essential to maintain the overall health and shape of Astragalus cusickii Gray var. sterilis (Barneby) Barneby. You can prune the plant in late winter or early spring before it starts actively growing. Pruning involves removing dead and broken branches, crossing limbs, weak branches, and any diseased foliage. It would be best to use sharp pruning shears to avoid injuring the plant. You can cut the shrub back by one-third of its current size to encourage bushier growth.
Propagation of Astragalus cusickii Gray var. sterilis (Barneby) Barneby
Astragalus cusickii Gray var. sterilis (Barneby) Barneby, also known as Sterile Milkvetch, can be propagated through various methods such as seed propagation and vegetative propagation.
Seed Propagation
The seeds of Astragalus cusickii Gray var. sterilis can be collected from mature plants during late summer. These seeds can be sown immediately into well-draining soil or can be stored in cool and dry conditions until the next spring. Before sowing, the seeds need to be scarified to improve germination rates.
The best way to scarify the seeds is through mechanical means such as rubbing on sandpaper or using a file or knife to make a small nick on the seed coat. The seeds are then sown into trays or pots filled with a well-draining potting mix. The seeds need to be lightly covered with soil and kept moist until they germinate, which can take up to several weeks.
Vegetative Propagation
Vegetative propagation is the process of using parts of the parent plant, such as stem cuttings, to produce new offspring. Astragalus cusickii Gray var. sterilis can be propagated through stem cuttings taken during spring or early summer. The stem cuttings should be taken from older plants, and only healthy and disease-free cuttings should be used.
The cuttings should be approximately 3-4 inches long, and cut just below a node or bud. Remove all the leaves from the lower half of the cutting, leaving only a few leaves at the top. The stem cuttings can be planted into a container filled with a well-draining soil mix. The cuttings should be kept in a cool, shaded area and kept moist until new roots start to develop, which can take several weeks.
Disease and Pest Management for Astragalus cusickii Gray var. sterilis (Barneby) Barneby
As with any plant, Astragalus cusickii Gray var. sterilis (Barneby) Barneby is susceptible to a variety of diseases and pests. It's important to monitor your plants regularly for signs of infestation or disease so that you can catch any problems early and prevent them from spreading. Here are some common diseases and pests that may affect this plant:
Diseases
1. Root Rot: Root rot is a fungal disease that affects the roots of the plant, causing them to become mushy and decayed. To prevent root rot, make sure the soil is well-draining and that the plant is not over-watered.
2. Anthracnose: Anthracnose is a fungal disease that causes brown or black spots on the leaves of the plant. To prevent anthracnose, make sure the plant has good air circulation and avoid getting the leaves wet when you water.
Pests
1. Aphids: Aphids are small, soft-bodied insects that suck sap from the leaves of the plant, causing them to yellow and curl. To control aphids, you can use insecticidal soap or a strong blast of water to wash them off the plant.
2. Spider Mites: Spider mites are tiny pests that can be difficult to see with the naked eye. They feed on the plant's sap, causing yellow spots on the leaves. To control spider mites, you can use insecticidal soap or neem oil.
3. Whiteflies: Whiteflies are small, white insects that suck sap from the leaves of the plant. They can be controlled with insecticidal soap or neem oil.
It's important to remember that prevention is key when it comes to disease and pest management. Keep your plants healthy by watering them properly, providing good air circulation, and removing any diseased or infested plant material promptly. If you do need to use pesticides, make sure to follow the instructions carefully and use them only as a last resort.
