Thelypteris ×invisa (Sw.) Proctor (pro sp.)
Thelypteris ×invisa (Sw.) Proctor (pro sp.), also known as the ghost fern, is a hybrid fern that is believed to be a cross between Thelypteris noveboracensis and Thelypteris palustris. The plant was first discovered in the United States in the early 1900s growing in wetlands and moist forested areas.
Common Names
In addition to being known as the ghost fern, Thelypteris ×invisa is also commonly referred to as the invisible fern and the lax water fern. These names likely stem from the plant's ability to blend in with its surroundings while still being a beautiful addition to any garden or landscape.
Appearance
Thelypteris ×invisa has dark green, triangular-shaped fronds that grow up to 2 feet in length. The plant can reach a height of 3 feet and has a spreading, clumping habit that allows it to slowly colonize an area over time. The fronds have a delicate, lacy appearance and are held on wiry, dark-colored stems that contrast nicely with the green foliage.
Uses
Thelypteris ×invisa is an excellent choice for anyone looking to add some texture and interest to a moist or wet area in their garden or landscape. The plant is hardy and easy to care for, and can be grown in a variety of soil types. It is also a popular choice for use in rain gardens and near water features, where its spreading habit and attractive foliage make it a standout plant.
Light Requirements
Thelypteris ×invisa commonly grows in partial to full shade, making it ideal for growing under trees or in a partially shaded area. This type of fern prefers filtered light as harsh direct sunlight may cause the leaves to scorch or dry out.
Temperature Requirements
Thelypteris ×invisa requires moderate temperatures for optimal growth and develops best where the average daily temperature ranges from 60 to 75 degrees Fahrenheit. This plant is winter hardy in USDA Zones 8-11, but it may not survive harsh winter conditions if not properly protected.
Soil Requirements
The growth of Thelypteris ×invisa is not overly dependent on soil type and can grow in a variety of well-draining soil types ranging from sandy loam to heavy clay soils. However, it grows best in neutral to slightly acidic soils, with a pH of 6.5-7.0. To ensure optimal growth, the soil should be kept consistently moist, but not waterlogged.
Cultivation of Thelypteris ×invisa
Thelypteris ×invisa, commonly known as the shady maiden fern, is a hybrid of two species of ferns. Here are some tips for cultivating them successfully.
Watering Needs
The shady maiden fern likes moist soil, but it should not be overwatered. The soil should remain consistently moist but not waterlogged. The frequency of watering will depend on the location and climate you live in. Water the plant when the top layer of soil appears dry and the fronds start to droop.
Fertilization
Thelypteris ×invisa is not a heavy feeder, but it would appreciate some extra nutrients now and then. Fertilize the plant with a balanced, all-purpose fertilizer once or twice a month during the growing season (spring and summer) to encourage healthy growth. Avoid fertilizing the plant during winter when growth is slow.
Pruning
Pruning of the shady maiden fern is not necessary, but it can be done to remove any damaged or unsightly fronds. Use a clean and sharp pair of pruning shears to cut back the fronds at the base of the plant.
Thelypteris ×invisa is a beautiful plant to grow. With adequate moisture, occasional feeding, and pruning, you can enjoy a healthy and lush fern that can add life to any space.
Propagation of Thelypteris ×invisa
Thelypteris ×invisa can be propagated through spores or division.
Propagation through spores
Propagation through spores is a popular method for growing Thelypteris ×invisa. It involves collecting mature fronds, sterilizing them, and allowing them to mature until spores are produced. The spores can then be planted in a sterile substrate, such as peat moss or agar, and grown in a humid environment until they develop into young ferns.
Propagation through division
Propagation through division involves splitting the plant into smaller sections, each with its own root system. This can be done by carefully separating the plant at the root system, making sure each section has enough roots to independently support its growth. The divided sections can then be replanted in soil, and regularly watered until established.
Both propagation methods require special attention and care, and it is recommended that they are done under the guidance of experienced gardeners or horticulturists.
Disease Management
Thelypteris ×invisa is a relatively disease-resistant plant, but there are still some diseases that can affect it. Below are the common diseases and suggested ways to manage them:
Leaf Spot
Leaf spot is a common disease that affects many ferns, including Thelypteris ×invisa. It is caused by a fungal or bacterial infection and can result in brown or black spots on the leaves. The best way to manage leaf spot is to remove infected leaves and avoid overhead watering. Additionally, applying a fungicide may help control the spread of leaf spot.
Rust
Rust is a fungal disease that affects the undersides of the leaves, causing orange or brown spots. It can be managed by removing infected leaves and applying a fungicide. Additionally, avoiding overhead watering and increasing air circulation can help prevent rust.
Pest Management
Thelypteris ×invisa can also be affected by pests. Below are the common pests and suggested ways to manage them:
Spider Mites
Spider mites are tiny pests that feed on the undersides of the leaves. They can cause yellowing and wilting of the leaves. To manage spider mites, remove affected leaves and spray the plant with water to increase humidity. Additionally, a miticide may be necessary to control the infestation.
Scale Insects
Scale insects are small pests that feed on the sap of the plant, causing yellowing and wilting of the leaves. They are often found on the undersides of leaves or on stems. To manage scale insects, remove affected leaves and stems and apply a horticultural oil or insecticide. Additionally, increasing air circulation and avoiding over-fertilization can help prevent scale insects from infesting the plant.
