Tree ferns, known botanically as the genus Dicksonia, are subtropical and tropical species that share most of the same characteristics and cultural needs of more common fern houseplants, simply on a much larger scale. Tree ferns grow in warm, moist climates and in well-controlled indoor environments. According to Clemson University, tree ferns can reach up to 45 feet in height when there is ample room and favorable conditions.
Provide growing conditions where ambient temperatures consistently remain at 60 to 70 degrees F during daylight hours and between 50 and 60 degrees F throughout the night.
Give bright indirect light, filtered sunlight or partial daily shade throughout the year, and avoid any extended period of direct sunlight, particularly in summer.
Water your tree fern liberally to keep the soil evenly moist at all times but not sopping wet, as this can cause trunk rot. Provide high ambient humidity by frequent misting with water or by constant use of humidifiers when growing indoors, particularly when HVAC systems are used.
Feed your tree fern frequently but lightly, using a basic water-soluble, indoor plant fertilizer. Apply once a month during the main growing season from April to September. Follow the product label dosing directions, but cut the fertilizer amount in half while still using a full volume of water to dilute it. Skip fertilizing new plants or recently transplanted containerized tree ferns for an interval of six months to allow the roots to develop in the new soil.
Prune away the dead fronds only when they become brown and desiccated. Cut the frond stem off next to the trunk, being careful not to tug the frond or to cut into the trunk tissues.
Mulch around your tree ferns growing outdoors with a few inches of good quality compost each year. This will boost the organic matter in the soil and gently provide macro and micro nutrients to the fern. Keep the compost roughly 6 inches from the trunk, and extend to past the outer perimeter of the drip line by at least 12 inches.