Origin
Polystichum braunii ssp. purshii, commonly known as Pursh's Holly Fern, is native to North America. It is found in Alaska, Canada, and the contiguous United States, including the Pacific Northwest and the Appalachian Mountains.
Common Names
Besides its scientific name, this fern is known by other common names such as Brauns' holly fern, Braun's Hollyfern, Pursh's hollyfern, and Western-ear hollyfern.
General Appearance
Polystichum braunii ssp. purshii is a small to medium-sized evergreen fern that grows in a clumping habit. Its fronds, which can range from 30 to 70 cm in length, are pinnate with glossy, dark green leaflets that are erect and leathery to the touch. The leaflets are pinnatifid, meaning that they are divided into lobes but not fully separate. The fronds emerge from a thick rhizome, which is covered in brown scales and serves as a storage organ.
The sori (spore-bearing structures) of Polystichum braunii ssp. purshii are located on the under surface of the leaflets. They are covered by kidney-shaped indusia that are light to dark brown. The spores mature in mid-summer to early autumn.
Uses
Polystichum braunii ssp. purshii is not commonly used for commercial purposes. However, it is highly valued by gardeners and landscapers for its beauty and hardiness. It is used in rock gardens, woodland gardens, and as a groundcover in shaded areas. It prefers well-drained, moist soil and partial to full shade. It is an excellent choice for adding texture and depth to shady areas.
Light Requirements
Polystichum braunii ssp. purshii requires partial to full shade to thrive. Excessive exposure to sunlight can cause the leaves to scorch and dry out.
Temperature Preferences
This plant typically grows well in cool environments with average temperatures ranging from 55°F to 75°F (12°C to 24°C). Polystichum braunii ssp. purshii can tolerate occasional freezes but is not suited for extremely hot or dry conditions.
Soil Requirements
The Polystichum braunii ssp. purshii prefers moist, well-drained soil and will not thrive in dry or waterlogged conditions. This plant is adapted to acidic to slightly neutral soils, requiring a pH range between 5.0 and 7.0 for optimal growth. It can also tolerate a range of soil textures, including loam, clay, and sand.
Cultivation method
Polystichum braunii ssp. purshii grows best in partially shaded areas, making it suitable for undergrowth plantings. It prefers a well-draining soil with a slightly acidic pH level. It is ideal for USDA zones 5-9 and can grow up to a height of 2-3 feet.
Watering needs
Polystichum braunii ssp. purshii requires regular watering during its growing season, especially during hot and dry weather. It is best to water it at the soil level, and avoid overwatering as it can cause root rot. Once established, it can withstand short periods of drought, but it is still important to keep it hydrated throughout the growing season.
Fertilization
Polystichum braunii ssp. purshii is not a heavy feeder, but regular fertilization can help enhance its growth and health. Fertilize once a year, in the spring or fall, with a slow-release, balanced fertilizer. Do not over-fertilize, as it can lead to salt build-up in the soil, damaging the plant.
Pruning
Polystichum braunii ssp. purshii may require pruning to maintain its shape and size. It is best to prune it in early spring before the new growth appears. Remove any damaged, diseased, or dead fronds, and trim back any overcrowded growth from the center of the plant. Try to avoid pruning more than one-third of the plant, as it can weaken it.
Propagation Methods for Polystichum braunii (Spenner) Fée ssp. purshii (Fern.) Calder & Taylor
There are several ways to propagate Polystichum braunii (Spenner) Fée ssp. purshii (Fern.) Calder & Taylor, including spores and division.
Propagation by Spores
Propagation by spores is a slow but effective method of producing new plants. The spores are produced by the underside of mature fronds and are typically released in late summer or early fall. To propagate by spores, you will need to collect the spores and sow them in a suitable growing medium.
To collect the spores, choose a healthy frond and cut it from the parent plant. Place the frond in a large paper bag and let it dry for a few weeks. After the frond is dry, gently shake the bag to release the spores. Sow the spores in a mixture of peat moss and sand and keep them moist and warm. It may take up to two years for the spores to germinate, so be patient.
Propagation by Division
Propagation by division is a faster method of producing new plants. It is best to divide Polystichum braunii (Spenner) Fée ssp. purshii (Fern.) Calder & Taylor in the spring when new growth is just beginning. To divide the plant, dig it up and carefully separate the crowns using a sharp knife or pruning shears. Each division should have several healthy fronds and a good root system.
After dividing, plant each section in a suitable location with well-draining soil and partial shade. Keep the soil moist and protect the new plants from extreme heat and cold until they become established.
Disease Management
Polystichum braunii ssp. purshii, commonly known as Pursh's shield fern, may be affected by several diseases. One of the most common diseases is leaf blight or leaf spots caused by fungal pathogens such as Botrytis cinerea and Alternaria spp. This disease causes the foliage to turn brown, wilt, and eventually die. It can be managed by removing infected leaves and maintaining good air circulation to prevent the buildup of moisture that facilitates fungal growth. The use of fungicides may also help to control the spread of the disease.
Another common disease is root rot, which is caused by fungal pathogens such as Phytophthora and Pythium spp. The disease is often characterized by stunted growth, yellowing leaves, and wilting. Control measures include avoiding over-watering and ensuring that the soil has good drainage. The application of fungicides may also help to manage the spread of the disease.
Pest Management
Pests that may attack Polystichum braunii ssp. purshii include scale insects, mealybugs, and spider mites. Scale insects can be identified by the presence of small, hard, and domed-shaped shells on the undersides of leaves and on stems. Mealybugs are characterized by their white, cotton-like appearance, which can be found in leaf axils and other protected areas on plants. Spider mites can be identified by the presence of fine webbing on the plant.
Control measures for these pests include the use of insecticidal soap, neem oil, and horticultural oil. These products should be applied according to instructions on the label. It is also important to regularly inspect the plant for signs of pest infestations and to isolate infected plants to prevent the spread of pests to other plants.
