Origin
Poa cusickii Vasey ssp. purpurascens (Vasey) Soreng is a native plant in North America, found in the western United States and Canada. It is known to grow in savannas, meadows, and open forests in various terrains, from lowlands to high mountains.
Common Names
Poa cusickii Vasey ssp. purpurascens is also commonly known as Cusick's bluegrass, mountain bluegrass, and purple mountain grass.
Uses
From its tough, wiry roots to its pale green leaves, Poa cusickii Vasey ssp. purpurascens is an important plant in many natural ecosystems, playing a vital role in soil stabilization and erosion control. Its seeds also serve as food for various herbivores like elk and deer. Moreover, it is a vital part of the landscape, providing aesthetic beauty to meadows and mountains where it is widely found.
General Appearance
Poa cusickii Vasey ssp. purpurascens is a perennial grass that grows from dense mats of fine, tough, wiry roots. It can grow up to 30 inches in height, with thin, pale green leaves that usually range from 1 to 10 inches long. The flower heads are open and spreading, and usually have a purplish tint. The seeds develop on stems that rise above the leaves and can be up to 6 inches tall. As a plant well-adapted to harsh conditions like rocky soil, drought, and cold temperatures, Poa cusickii Vasey ssp. purpurascens is an impressive sight to behold in the wild.
Light Conditions
Poa cusickii Vasey ssp. purpurascens prefer full sun to partial shade. It can tolerate a moderate amount of shade, but the growth rate and flowering will decrease if the plant does not receive enough sunlight.
Temperature
The ideal temperature range for Poa cusickii Vasey ssp. purpurascens growth is between 50 to 70 degrees Fahrenheit. It can tolerate extreme temperatures of up to 90 degrees Fahrenheit during the summer and temperatures as low as -15 degrees Fahrenheit during the winter. However, sustained exposure to these high or low temperatures can cause stress and damage the plant.
Soil Requirements
These grasses thrive in well-draining and nutrient-rich soils. The ideal soil pH should be between 6.5 to 7.5. This plant species can also tolerate slightly acidic to mildly alkaline soils. However, the plant should not be planted in waterlogged or compacted soils as this can affect root growth and lead to the development of various diseases.
Cultivation
Poa cusickii Vasey ssp. purpurascens (Vasey) Soreng grows well in full or partial sun and prefers moist, well-draining soil. It can tolerate occasional flooding, making it a good choice for streamside plantings.
The best time to plant Poa cusickii is in the early spring or fall. Plant in clumps or as a ground cover, spacing plants about 2-3 feet apart. Be sure to amend the soil with organic matter before planting to improve drainage.
Poa cusickii is a cool-season grass that grows best in areas with temperatures between 60-75 degrees Fahrenheit. It is cold tolerant and can survive in USDA zones 5-9.
Watering Needs
Poa cusickii has moderate water needs and likes to be kept moist but not waterlogged. Water deeply but infrequently, allowing the soil to dry out slightly between waterings. During periods of drought, you may need to water more frequently.
If planting near a water source, Poa cusickii can tolerate occasional flooding, but prolonged standing water can be detrimental to the health of the plant.
Fertilization
Poa cusickii is not typically a heavy feeder and does not require frequent fertilization. However, if the soil is poor, you can fertilize once a year in the early spring with an all-purpose fertilizer. Be sure to follow the fertilizer manufacturer's instructions for application rates and timing.
Too much nitrogen can cause the grass to grow too quickly and become susceptible to diseases and pests, so be careful not to over-fertilize.
Pruning
Poa cusickii requires minimal pruning but can benefit from a light trimming in the late winter or early spring. This will help to remove any dead or damaged foliage and encourage new growth. Be sure to only cut back about one-third of the plant's height.
For a more formal appearance or to prevent self-seeding, you can prune Poa cusickii after it flowers in the summer. Cut back the flower heads before they mature and set seed.
Propagation of Poa cusickii Vasey ssp. purpurascens (Vasey) Soreng
Poa cusickii Vasey ssp. purpurascens (Vasey) Soreng, commonly known as Cusick's bluegrass or purple mountain bluegrass, is a native grass species found in North America. Propagating this plant can be achieved through seeds or division of clumps.
Propagation by seeds
The seeds of Poa cusickii can be collected from the mature plant when they turn brown and start to fall off the plant. Collect the seeds by shaking the seed heads upside down into a container. The seeds can be stored in a dry container until ready for use.
Poa cusickii seeds can be sown directly into the soil, preferably in the fall or early winter. However, they can also be started indoors in late winter or early spring and transplanted when the weather permits. The planting area should be cleared of any debris, and the soil should be loosened with a rake or fork before planting.
The seeds should be sown thinly and covered with a thin layer of soil (about 1/4 inch deep) and gently pressed down. They should be kept moist until they germinate, which can take anywhere from 1-3 weeks.
Propagation by division of clumps
The division of clumps is another method of propagating Poa cusickii. This is done by digging up an established clump and dividing it into smaller sections. Each section should have a few roots and good top growth.
The divided sections should be replanted in a well-prepared area with good soil drainage. The planting depth should be the same as the previous depth, and the soil should be firmed around the plant to avoid any air pockets.
The best time for dividing clumps is in the early spring when the plant is just emerging from its dormant state. This allows the plant time to establish itself before the summer heat arrives.
Disease Management
Poa cusickii Vasey ssp. purpurascens (Vasey) Soreng may be vulnerable to diseases such as Pythium root rot, leaf rust, and dollar spot. Pythium root rot may result in wilting and yellowing of leaves, as well as root rot. Leaf rust may cause the leaves to appear spotty and reddish, while dollar spot may result in the formation of small, circular spots on the leaves, which can eventually turn brown and merge together.
To manage Pythium root rot, it is essential to provide excellent drainage and avoid overwatering. In cases where the disease has already taken hold, applying fungicides such as mefenoxam and metalaxyl can help control the spread of the fungus. For leaf rust and dollar spot, fungicides like propiconazole and azoxystrobin applied according to the manufacturer's directions may be helpful in managing the disease.
Pest Management
Common pests that may trouble Poa cusickii Vasey ssp. purpurascens (Vasey) Soreng include aphids, armyworms, and cutworms. Aphids can suck out sap from the leaves of the plant, causing them to curl and distort. The armyworms and cutworms usually feed on the leaves, clipping or chewing them, which can result in significant damage to the plant.
To control aphids, it may be helpful to introduce natural predators such as ladybugs and lacewings into the environment. Applying insecticides such as neem oil can also help control their spread. To control armyworms and cutworms, it is best to use insecticides such as chlorantraniliprole or spinosad. It is vital to read the instructions on the insecticide label to apply the product correctly.
