Overview
Dicksonia squarrosa, commonly known as the Rough Tree Fern or Wheki in Maori, is a species of large tree fern belonging to the family Dicksoniaceae. It is native to the southern hemisphere, specifically found in New Zealand, Australia, and parts of South America.
General Appearance
The Rough Tree Fern is a large plant that can grow up to 10 meters tall, with fronds up to 4 meters in length. The trunk is covered with dark brown or black scales, giving it a rough and scaly texture. The fronds are broad and felty, with a bright green color that allows the fern to stand out amongst other green foliage.
Uses
In New Zealand, the Rough Tree Fern has been used for hundreds of years by the Maori people. The young leaves of the fern were used to cover food while it was being cooked in a hangi (earth oven) or to wrap food in for storage. The trunks were also used to make shelter and bedding for travelers. In modern times, Rough Tree Ferns are popular ornamental plants for gardens and public spaces due to their unique appearance.
Additionally, the Rough Tree Fern plays an important role in the environment by providing habitat and shelter for insects, birds, and other small animals.
Light Requirements
Dicksonia squarrosa typically prefers a partially shaded area with dappled sunlight. Direct sun exposure can result in leaf scorching, while deep shade can slow down the plant's growth rate and cause stunting.
Temperature Requirements
As a native of New Zealand, Dicksonia squarrosa thrives in cooler temperatures. Ideally, the plant should be kept in an environment with a temperature range of 50-77°F (10-25°C). This makes it a great plant for gardens in temperate and subtropical regions.
Soil Requirements
The soil should be well-draining and rich in organic matter. Dicksonia squarrosa does not do well in soil that is too heavy or waterlogged. The ideal pH range for the soil is between 5.0 and 7.5. Adding mulch or compost to the soil can help retain moisture and improve its overall quality.
Cultivation
Dicksonia squarrosa is a popular fern species that can grow up to 15 meters tall and 2 meters wide. To cultivate this species, it is vital to create a conducive growing environment for it.
Start by selecting a site that receives partial to full shade. Dicksonia squarrosa thrives best in areas with high humidity, ample rainfall, and cool temperatures. For optimal growth, plant the fern in well-draining soil with a pH of 5.5 to 6.5.
It is crucial to ensure that the planting site has adequate space for the fern to grow. The roots of Dicksonia squarrosa like to spread out, and the planting hole should be two times bigger than the root ball of the plant.
Watering
Proper watering is essential for the growth and survival of Dicksonia squarrosa. The fern requires frequent watering, especially during the warm and dry season. However, you must avoid over-watering the fern as it can lead to rot and other fungal diseases.
During the growing season, the soil around the fern should be kept moist, but not saturated. Ensure that the soil remains damp but not soaked through and through. During the winter months, reduce watering to prevent waterlogging and rotting of the roots.
Fertilization
Dicksonia squarrosa doesn't require frequent fertilization. However, it would help if you fertilized the plant once every two months during the growing season. Use a slow-release or liquid fertilizer with balanced nutrients. The fertilization schedule is essential, as it ensures that the plant has enough nutrients to support healthy growth.
When applying fertilizer, follow the manufacturer's instructions carefully to avoid over-fertilizing the plant. Too much fertilizer can cause the plant to grow too quickly, resulting in weak stems and branches.
Pruning
Pruning is essential in maintaining the shape and size of Dicksonia squarrosa. Remove any old, damaged, or diseased fronds to allow new growth. Use a clean and sharp pair of garden shears to avoid damaging the healthy parts of the fern.
Pruning in spring or early summer is ideal since new growth is at its peak. Avoid pruning in fall, as it might damage the fern and increase its susceptibility to diseases.
Propagation of Dicksonia squarrosa
The propagation of Dicksonia squarrosa can be methodically achieved from spores or through division of existing plants. The plant, also known as the soft tree fern, thrives in temperate and tropical regions worldwide. This fern parent species is stirred in shaded forest areas stretching from Australia to Fiji, Indonesia, and New Zealand. Propagating Dicksonia squarrosa is an essential practice for maintaining and expanding the fern population.
Propagation by spores
Propagation by spores is a common technique for cultivating ferns, including Dicksonia squarrosa. Spores are tiny reproductive units found in the brown fronds of mature ferns. These spores develop into gametophytes that gradually generate new ferns. However, spores’ propagation process is daunting and precarious as it requires some skill, patience, and special equipment.
To propagate Dicksonia squarrosa from spores, you must start by collecting spores from mature fronds. Then, sterilize the spores to remove any contamination, such as bacteria and fungi. The sterile spores can then be scattered on a moist, nutrient-rich medium such as peat moss, placed in a humid environment, and covered. In about 6-12 months, tiny green leaf-like structures called prothalli will begin to grow. As the prothalli develop, select the healthiest and most robust ones and replant them into individual growing containers. After about a year or two of growth, the young ferns will be ready for planting outdoors.
Propagation through division
Propagation through division is a more efficient and popular propagation method for Dicksonia squarrosa. This method involves dividing existing mature plants into smaller portions which can develop into new plants. Division is an ideal propagation method for mature ferns that have grown large enough to produce multiple natural planting zones referred to as 'clumps.'
The first step in dividing Dicksonia squarrosa is to choose a sturdy fern plant that has ample planting zones. Then, uproot the fern plant cautiously, paying attention not to damage the roots. Afterwards, shake the roots lightly to remove the soil attached to them, thereby exposing the clumps. Using a sharp, sterilized knife, divide the clumps into smaller sections. Each divided part should have a sufficient amount of roots intact to secure the plant's stability and growth. The divided parts can be planted in an appropriate substrate such as fertigated soil in grow bags, water until established, and kept in a shaded area while they develop into new fern plants.
Disease and Pest Management for Dicksonia squarrosa (G. Forst.) Sw.
Dicksonia squarrosa, commonly known as the New Zealand tree fern, is a popular ornamental plant, prized for its unique appearance. However, like all plants, it is susceptible to various diseases and pests that can cause significant damage if left unchecked. Here are some common diseases and pests that can affect the plant and some ways to manage them:
Diseases
Crown rot: Crown rot is a fungal disease that affects the base of the plant's fronds, and it can cause the plant to wilt and eventually die. To prevent this disease, avoid overwatering and improve the soil drainage. If a plant does get infected, remove the affected fronds and apply a fungicide to prevent further spread.
Leaf spot: Leaf spot is a fungal disease that causes brown or black spots on the fronds. This disease thrives in damp conditions, so it is important to avoid overhead watering. If a plant does get infected, remove the affected fronds and improve the air circulation around the plant. A fungicide may also be necessary to prevent further spread.
Pests
Scale insects: Scale insects are common pests that can cause yellowing or wilting of the fronds. They are typically found on the undersides of fronds and can be difficult to spot due to their small size. To manage scale insects, use a soft-bristled brush or cotton swab dipped in rubbing alcohol to remove them from the plant. If the infestation is severe, a pesticide may be necessary.
Mealybugs: Mealybugs are another common pest that can cause yellowing or wilting of the fronds. They are typically found on the undersides of fronds or in tight spaces between fronds. To manage mealybugs, use a soft-bristled brush or cotton swab dipped in rubbing alcohol to remove them from the plant. A pesticide may be necessary if the infestation is severe.
Thrips: Thrips are tiny insects that can cause discoloration and distortion of the fronds. They are typically found on the undersides of fronds and can be difficult to spot. To manage thrips, use a pesticide that is specifically labeled for thrips.
With proper care and vigilance, most diseases and pests that affect the Dicksonia squarrosa can be managed effectively. Regular inspection of the plant, proper watering, and adequate air circulation are essential to maintaining a healthy plant.
