How to Grow Kimberly Queen Ferns

Kimberly queen fern leaves from overhead

The Spruce / Gyscha Rendy

The Kimberly queen fern (Nephrolepis obliterata) is a bold and beautiful plant native to Australia that is characterized by large, gracefully arching fronds. Hardy in USDA zones 9-11, these ferns can be successfully grown outdoors in warm regions, as container plants that are overwintered indoors, or as houseplants.

Also commonly known as the sword fern due to its upright fronds, the Kimberly queen fern is considered a clean air plant, and is great for reducing indoor air pollution and toxins within your home.

  Botanical Name   Nephrolepis obliterata
  Common Name  Kimberly queen fern, sword fern
  Plant Type  Evergreen fern
  Mature Size  3 feet tall
  Sun Exposure  Partial sun, shade
  Soil Type  Moist but well-drained
  Soil pH  Acidic (6.1-6.5)
  Bloom Time  N/A
  Flower Color  N/A
  Hardiness Zones  9-11, USA
  Native Area  Australia
  Toxicity  Non-toxic

Kimberly Queen Fern Care

Kimberly queen ferns are fast-growing and require special care and attention in order to thrive indoors as houseplants. As with most ferns, this plant needs consistent humidity and moisture, which can be difficult to find in the average household environment. However, Kimberly queen ferns thrive in containers and with supplemental humidity can do well when grown indoors.

While they don’t require pruning, regularly removing any dead or dying fronds from your Kimberly queen fern will help to encourage new and healthy growth on a consistent basis.

Kimberly queen ferns potted in three hanging baskets

The Spruce / Gyscha Rendy

Kimberly queen fern fronds and leaves planted in ground

The Spruce / Gyscha Rendy

Kimberly queen fern leaves closeup

The Spruce / Gyscha Rendy

Light

Kimberly queen ferns thrive in medium indirect light to low light conditions. When grown indoors, they do well next to a bright window such as a north-facing window. Avoid harsh, direct sun as this can burn the delicate fronds. When grown outdoors, a shaded location that receives dappled sun is ideal.

Soil

A rich, moist but well-draining soil mixture is ideal for Kimberly queen ferns. A standard potting mixture with added peat for additional drainage is sufficient.

Water

As with most ferns, this plant requires sufficient moisture in order to thrive and the soil should never be allowed to dry out completely. Water well once the top one to two inches of soil is dry. Depending on the growing season and the amount of light that your fern is getting, you may need to water your Kimberly queen fern multiple times a week to keep it happy. 

These ferns can be sensitive to hard water. If you have tap water that has lots of salt, fluorine, or chlorine in it you may need to switch to filtered water. 

Temperature and Humidity

Kimberly queen ferns thrive in temperatures between 60-70 degrees Fahrenheit and cannot tolerate frost. When grown indoors, this means that you should keep your fern away from any drafty or cold windows. Ferns are popular additions to bathrooms for this reason. When grown outdoors, ensure that you overwinter the fern indoors if you are in a region that experiences cold winters. 

This species requires abundant humidity and the fronds will quickly turn crispy in dry environments. Adding a humidifier next to your Kimberly 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. 

Fertilizer

Abundant feeding is not required, but this fern can benefit from monthly fertilization. During the active growing season (the spring and summer) apply a balanced liquid fertilizer once a month to encourage healthy growth. 

Are Kimberly Queen Ferns Toxic?

Pet owners rejoice! Kimberly queen ferns are non-toxic to cats, dogs, and humans.

How to Grow Kimberly Queen Ferns From Spores

Growing Kimberly queen ferns from spores is a fascinating and easy process. Spores grow naturally on the fronds of established ferns as the plant’s natural 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 underside 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 10-12 days, remove the paper bag. You will find that the inside of the bag is coated in brown dust - the spores of the fern. 

Shake out the spores on top of moistened sphagnum moss and propagating medium in shallow germination trays, and cover with the tray lid. Ensure that the sphagnum moss and potting medium remain 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 - ensuring 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, and as the ferns age you can gradually transition to regular Kimberly queen fern watering and feeding schedules. 

Potting and Repotting Kimberly Queen Ferns

The Kimberly queen fern does well when root bound and doesn’t require frequent repotting. However, once the pot is filled with roots you can repot the plant into a pot that is two to three inches larger.

Ensure that the pot you choose has drainage holes to prevent waterlogging the soil, and avoid fertilizing your fern for at least a month after repotting to avoid burning the delicate roots.

Common Pests/Diseases

Ferns in general are not overly prone to infestations and the Kimberly queen fern is no exception. However, when grown as a houseplant it is susceptible to the usual range of common houseplant pests including aphids, mealy bugs, spider mites, and fungus gnats. Use an insecticidal soap to prevent and treat pest infestations.