The Kimberley queen fern (Nephrolepis obliterata) is a lush evergreen plant characterized by its large, gracefully arching, sword-shaped fronds. Overall, the plant has an upright, bushy growth habit. These ferns can be successfully grown outdoors in warm regions, as container plants that are overwintered indoors or as completely indoor houseplants. They have a fairly quick growth rate and are best planted in the spring.
The Kimberley queen fern is an indigenous Australian species. Its common name comes from the Kimberley region of Australia and the earl of Kimberley, who was the secretary of state for the British colonies in the 1800s. The preferred common name is sword fern.
|Botanical Name||Nephrolepis obliterata|
|Common Names||Kimberley queen fern, sword fern|
|Mature Size||2–3 ft. tall, 2–4 ft. wide|
|Sun Exposure||Partial, shade|
|Soil Type||Moist, well-drained|
|Soil pH||Acidic, neutral|
|Hardiness Zones||9–11 (USDA)|
Kimberley Queen Fern Care
As with most ferns, the Kimberley queen fern needs consistent humidity and moisture to thrive. This can be difficult to find in the average household environment if you're growing your plant indoors. However, the ferns do take well to container growth. Just be sure to water regularly and provide supplemental humidity as needed.
Furthermore, these plants don’t require regular pruning. However, removing any dead, damaged, or diseased fronds as they arise will help to encourage new and healthy growth.
Kimberley queen ferns thrive in partial sun to low light conditions. When grown indoors, they do well next to a bright window in indirect light. Avoid harsh, direct sun as this can burn the delicate fronds. When grown outdoors, a shaded location that receives dappled sunlight is ideal.
A rich, moist, well-draining soil mixture is ideal for Kimberley queen ferns. A standard potting mixture with added peat for additional drainage is sufficient.
As with most ferns, this plant requires sufficient moisture to thrive. The soil should never be allowed to dry out completely. But it should have good drainage, so the plant isn't waterlogged. Water deeply whenever the top 1 to 2 inches of soil dry out. Depending on the amount of heat and light that your fern is getting, you might need to water multiple times a week. Note that these ferns can be sensitive to hard water. If you have tap water with lots of salt, fluorine, or chlorine in it, you might need to switch to filtered water.
Temperature and Humidity
Kimberley queen ferns thrive in temperatures between 60 and 70 degrees Fahrenheit, and they cannot tolerate frost. When grown indoors, this means you should keep your fern away from any drafty or cold windows. When grown outdoors, ensure that you bring the fern indoors if your area is expecting frost.
This species requires abundant humidity, and the fronds will quickly turn crispy in dry environments. Adding a humidifier next to your Kimberley queen fern will keep it happy indoors, or you can place it on a pebble tray filled with water to increase the humidity around the plant.
Abundant feeding is not required, but this fern can benefit from regular fertilization. During the active growing season (the spring and summer) apply a balanced liquid fertilizer once a month to encourage healthy growth.
How to Grow Kimberley Queen Ferns From Spores
Growing Kimberley queen ferns from spores is a fascinating and easy process. Spores grow naturally on the fronds of established ferns as the plant’s way of reproducing (like seeds for other plants). Fern spores are so small that they are only visible to the naked eye when multiple spores are crowded together, which will look like small brown dots on the undersides of the fronds.
To collect and germinate spores from an existing fern plant, place a paper bag around a frond and secure it gently to the base. Adding a small stake as support for the frond and the bag will ensure that the delicate frond doesn’t break under the additional weight. After 10 to 12 days, remove the paper bag. You will find that the inside of the bag is coated in brown dust—i.e., the spores of the fern.
Shake out the spores on top of moistened sphagnum moss and propagating medium in a shallow germination tray, and cover with the tray lid. Ensure that the sphagnum moss and potting medium remain consistently moist as the spores germinate.
The first signs of spore germination will resemble a thin layer of moss on the top of the potting medium, after which you will begin to see small fronds appear. Once the fronds are visible, provide the ferns with a bit of air circulation by leaving the germination tray lid slightly open. Continue to ensure that the fronds and the potting medium remain moist. About a week after the fronds have appeared, remove the lid entirely.
Once the ferns are large enough to handle, begin transplanting them in groups of four to five into small plastic pots with a well-draining potting medium. Ensure that they remain moist as they mature. As the ferns age, you can gradually transition to a typical Kimberley queen fern watering and feeding schedule.
Potting and Repotting Kimberley Queen Ferns
When potting, ensure that the container you choose has drainage holes to prevent waterlogging the soil. Also, avoid fertilizing your fern for at least a month, so you don't burn the delicate roots.
The Kimberley queen fern does well when root bound, so it doesn’t require frequent repotting. However, once the pot is filled with roots that are popping up above the soil and out through the drainage holes, it's time to repot. Choose a container that is 2 to 3 inches larger that the one it was in.
Common Pests and Diseases
Ferns in general are not overly prone to serious issues with pests and diseases, and the Kimberley queen fern is no exception. However, when grown as a houseplant it is susceptible to the usual range of common houseplant pests, including aphids, mealybugs, spider mites, and fungus gnats. Use an insecticidal soap to treat infestations.