How to Grow and Care for Australian Tree Fern

Contrary to its name, the Australian tree fern (Cyathea cooperi) is actually more tree than fern. Characterized by lacy, feathery fronds and a scale-covered trunk, the evergreen Australian tree fern can bring an exotic touch to any garden. It's best planted in the early spring and prefers warm temperatures and partial shade year-round.

Some species of Cyathea are the tallest tree ferns. In their native habitat of Australia, a tree fern can grow up to 50 feet tall. This tropical plant is easily too tall for most indoor growing situations except for large conservatories and greenhouses. It can grow an additional foot or two each year.

The plant has naturalized itself in Hawaii, where it's regarded as invasive due to its fast growth and prolific self-propagation via its spores.

Common Name	Australian tree fern, Cooper's tree fern, lacy tree fern, scaly tree fern
Botanical Name	Cyathea cooperi
Family	Cyatheaceae
Plant Type	Evergreen fern
Mature Size	Typically 15–25 ft. tall, 10–12 ft. wide; up to 50 ft. tall in the wild
Sun Exposure	Partial sun
Soil Type	Moist, well-drained
Soil pH	Neutral, acidic
Hardiness Zones	8–11 (USDA)
Native Area	Australia

Australian Tree Fern Care

Plant Australian fern trees in well-draining soil in an area that gets plenty of sunlight. If you're growing this tree in a cooler area in a pot, move it indoors in winter. The key to growing a healthy Australian tree fern is to provide it with dappled sunlight or shade, ample humidity, and consistently moist soil.

Planting

Plant Australian tree fern in an area that gets partial or dappled sunlight, protected from midday sun. The best time to plant these trees is in early spring so that they can quickly start growing as the days get longer. To plant, dig a hole that's twice the size of the root ball, place the tree into the hole, backfill the hole with soil, and water in the tree.

Light

Although Australian tree ferns are shade-loving plants in general, they can also thrive in partial sun or dappled sun locations where they receive six hours of light a day. Keep in mind that the more direct sunlight the plant receives, the more likely it is that you'll need to increase your watering schedule.

Soil

Australian tree ferns can tolerate a variety of soil conditions including sand, loam, and clay. That being said, they will thrive best in a moist, loamy mixture that is rich but well-draining with a neutral to acidic pH level. It's also recommended that you add a layer of mulch around the tree, which will add more nutrients to the soil and act as a barrier to seal in moisture (particularly during very hot weather).

Water

Keep the soil moist at all times. Australian tree ferns are not drought-tolerant and need weekly watering. In extremely dry weather conditions, their need for moisture and humidity is extremely important. Avoid watering the crown directly because it can cause rot—instead, water the trunk and ensure the soil is consistently moist.

Temperature and Humidity

Australian tree ferns like a consistently warm and humid environment with temperatures ranging from 65 to 80 degrees Fahrenheit. Australian tree ferns do not acclimate well to rapid changes in humidity or temperature, which can result in browning fronds. In colder areas, you can grow the fern in a container, which gives you the flexibility to move it indoors for the fall and winter once temperatures drop too low.

Fertilizer

During the growing season, feed your Australian tree fern monthly with a liquid fertilizer. Larger specimens are heavier feeders and might require feeding every other week year-round. For the amount of fertilizer to use, follow the instructions on the fertilizer label.

Types of Australian Tree Ferns

About 1,000 different kinds of tree ferns are found in tropical or subtropical settings.

• 'Brentwood' is a cultivar that grows faster than most tree ferns and is larger with darker green fronds than the species.
• The New Zealand or Tasmanian tree fern is closely related, but the species is actually Dicksonia antarctica, and it tends to have a narrower crown than the Australian tree fern (but has similar requirements).

Propagating Australian Tree Fern

As ferns, Australian tree ferns reproduce naturally through spores. They do no produce seeds, and you cannot propagate them from cuttings. You can try propagating them via spores with this method:

1. Collect the spores from a mature frond onto a piece of paper.
2. In a heatproof bowl, pour boiling water over soilless potting medium to sterilize it and remove any pathogens, which can affect germination. Let the potting mix drain and cool completely before filling it into a four-inch pot.
3. Sprinkle the spores on the potting mix and cover it with a plastic dome or bag.
4. Place the pot in a location with a consistent temperature of around 68 degrees Fahrenheit and indirect light.
5. Keep it moist at all times, The spores will take 2 to 6 weeks to germinate.

Potting and Repotting Australian Tree Ferns

If you're growing your tree fern in a container, repot it annually into a larger pot (with fresh soil). Because the tree fern is susceptible to root rot, make sure the container has large drainage holes. Plastic pots don't dry out as fast as clay pots, so they are generally more suitable.

When the plant reaches the maximum size allowed by the growing space, stop repotting to slow down its growth. Eventually, it will likely outgrow both the pot and the room.

Overwintering

The Australian tree fern is a fairly hardy tree fern that can tolerate occasional low winter temperatures of 20 degrees. If possible, plant Australian tree ferns near a building to protect them from strong winds.

In addition, the roots of Australian fern grown in containers can be damaged in the winter due to their lack of insulation. Winterizing the container by wrapping it with bubble wrap gives it extra protection. Do not water the crown of the plant over winter.

Common Pests & Plant Diseases

While the Australian tree fern doesn't have any major issues with diseases or pests, it can occasionally get mites or mealybugs. The first treatment recommendation is to spray the infestation with strong streams of water; if that doesn't work, treat the plant with neem oil or an insecticide until all signs of infestation have gone.

From: thespruce