Fern-tastic native plants for your indoors
If you are looking to create a lush, indoor jungle to call home, consider including native Tasmanian ferns in your plant palette. However, make sure you only buy them from reputable retailers to ensure our unique Gondwanan rainforests remain protected.
Tasmania has more than 50 species of fern, ranging from mighty tree ferns to small, floating Azolla, including the following which are suitable for indoor use, although with some limitations:
Adiantum aethiopicum (Common Maidenhair)
Asplenium bulbiferum (Hen and Chicken Fern)
Blechnum nudum (Fishbone Water Fern)
Cyathea australis (Rough Tree Fern)
Dicksonia australis (Man Fern or Soft Tree Fern)
Adiantum aethiopicum (Common Maidenhair)
Adiantum aethiopicum has a very delicate habit, but it is actually a quite vigorous suckering fern that can quickly form a large clump. It is very easily grown in a moist position in filtered sunlight. A. aethiopicum is the only member of this genus in Tasmania. It is a moderately common and very distinctive native fern that grows in dry places. It is a small fern with small, wedge- or diamond-shaped leaflets widely spaced on branched, wiry rachises.
Consider for use indoors in hanging baskets, plant stands, or table top planters.
Asplenium bulbiliferum (Hen and Chicken Fern or Mother Spleen Wort)
Asplenium bulbiliferum is a common native fern that grows in the understorey of wet forest throughout Tasmania. It grows on rocks (lithophytic), on the ground, or often as an epiphyte on Dicksonia antarctica. It is a moderate sized-fern with leaves up to 60cm long. These leaves are divided many times and darken with age. One of the most distinctive features of A. bulbiliferum is that it often produces bulbils, small plants growing from upper parts of the fronds. The only other Tasmanian fern to do this is Polystichum proliferum, which we have growing along the creek on our bush block. These are such easy plants to 'propagate', so you can have fun growing them.
Consider for use indoors dish garden, green wall, terraria (closed) or potentially as a kokedama.
Blechnum nudum (Fishbone Water Fern)
Blechnum nudum is a very common native ground fern in wet forests wherever they occur in Tasmania. It is a relatively large and hardy ground fern, sometimes developing a short trunk, and grows to ~1m. The fronds are erect and pale green, and can grow up to 1m long, although usually reach 60-70cm in length. B. nudum prefers a damp semi-shaded position, although it can handle some sun.
Consider for use indoors as a floor plant or green wall.
Cyathea australis (Rough Tree Fern)
Cyathea australis is a slender stemmed tree fern with fronds up to 2.5 m. It has a moderate to large trunk (often a few metres tall and 20-30cm in diameter) that is not fibrous.
The common name (Rough Tree Fern) refers to the trunk with its hard persistent stalks of old leaves, not the foliage itself, which is much softer than that of Dicksonia antarctica.
Consider for use indoors only when young, e.g. as a floor or feature plant. Unless you have a huge atrium or greenhouse in which you can control the humidity and has enough room for this fern to grow up. Remember though that this fern still needs shade, so how are you going to provide this?
Dicksonia antarctica (Man Fern or Soft Tree Fern)
Dicksonia antarctica is the only species of this genus in Tasmania and by far the most common tree fern on the island. It can be found in wet sclerophyll forest and rainforest throughout Tasmania (except in at high altitudes and on very nutrient poor sites). It has a thick fibrous trunk (often ~20-30cm wide at mid height), that may be as much as 15m tall, with long arching fronds to 2m. Its common name (Soft Tree Fern) refers to the fibrous trunk, not the foliage itself, which is much harder than that of the other tree ferns, e.g. Cyathea australis. D. antarctica prefers a sheltered, moist, cool, shaded position.
Like C. australis, consider D. antarctica for use indoors only when young. Remember though that this fern also prefers a shaded position, so how are you going to provide this in this environment? And where will you relocate it when it outgrows your indoor space?
Where to buy these plants?
Tasmanian rainforests are under threat from logging, mining and climate change. The harvesting of tree ferns from these native forests is highly contentious. Many large D. antarctica come from old growth forests being logged. Please buy your Tasmanian ferns only from reputable retailers, including the following:
Habitat Plants: Liffey (North)
Plants of Tasmania Nursery: Ridgeway (South)
Redbreast Plants: Flowerdale (North), Margate (South)
Wildseed Tasmania: Online - Note ferns sold as spore only
CULTIVATION & MAINTENANCE TIPS
These simple cultivation and maintenance tips apply to both native and exotic ferns grown indoors. This is not an exhaustive list, but hopefully it answers your basic questions and gives you enough information so that you know what questions you need to ask next.
You might think of this as 'aspect' in an outdoor landscape. Look at the environment in which these plants can be found naturally. How can you recreate this in your home? Ferns generally like a good deal of light, but not direct sun. Which room in your house has this filtered light? Do not place these ferns close to windows that receive the hot afternoon sun, i.e. on the western side of your home. The ferns listed above also like shelter from the wind and a humid environment, i.e. one which has similar conditions to those where it is found in 'the wild'.
Whilst your bathroom may seem like the ideal environment for your ferns, be mindful that they can also be places of quite severe temperature drops. Water droplets from your shower can cool and condense on surfaces in your bathroom if not extracted well. How can you keep the temperature relatively even? Also, avoid hot water splashing onto and burning the fronds.
Tip: Rotate your plant a quarter-turn each week to allow even light and therefore foliage development across the plant.
We do not really use 'soil' in indoor plantings. What we use instead is a fully constructed growing media, e.g. a potting mix. A growing medium provides physical support/anchorage, water, (dissolved) oxygen and (dissolved) nutrients to plants in the place of soil. Pay attention to your potting mix! A good quality substrate (without fungus gnats) is critical to ensuring that your fern's roots thrive and do not rot. Specialty fern potting mixes are available on the market or you may consider making your own mix. A good quality fern potting mix should contain both organic and inorganic materials. The organic material could include contain coir, peat moss, compost or a combination of those. The inorganic components provide for drainage, e.g. perlite, vermiculite, pumice. If you want to read more about this topic, check out this blog from Fern Gardening: 'The best potting mix for ferns'.
Tip: Buy an Australian Standard potting mix to ensure it is well drained, re-wets easily, has a suitable pH, and is free of pest and disease.
According to Hanks (1996), lack of humidity and dehydration is often responsible for the failure of ferns indoors. The trick is to keep the media in which your ferns are growing moist through regular and even watering. Ferns generally like some moisture around their roots at all times, but do not necessarily like waterlogging. Summer cooling (air conditioning) and winter heating of your home can adversely impact your ferns as they both dry indoor air, thereby reducing humidity. To maintain humidity, firstly place your ferns away from direct sources of heating and cooling, and mist their leaves with a water sprayer. Also, place your fern pots over water, sitting on top of some pebbles or similar and not actually in the water itself (root rot - no thanks!). As the water evaporates, humidity around the plant increases. New generation Plant Parents even purchase humidifiers for this purpose, although that is not necessarily required if you follow the simple tips listed above.
Many horticultural professionals claim that indoor plants suffer from overwatering, and rarely from underwatering. Too damp a potting mix attracts pests we just don’t want. More on that shortly. It also potentially leads to root and stem rot meaning your fern's roots cannot supply essential nutrients to the stem and leaves, and the leaves cannot provide the products of photosynthesis, e.g. sugars, to the roots.
So how do we know when to water our ferns? Well many of you may just stick your finger in the potting mix to find out. IF the top third of your finger comes out dry, well a watering is required. However, you can use a soil moisture meter to get a more accurate reading without disturbing the plant's root zone.
Tip: Consider placing your fern in a sub-irrigated planter to take the guess-work out of watering. These planters introduce water from the bottom, allowing the water to soak upwards to the plant through capillary action. You can even make your own sub-irrigated planter using a cover pot, elevated interior pot and wicking material.
Fertilise during periods of active growth, i.e. spring through to early autumn. Whilst seaweed and fishmeal solutions are excellent tonics, consider the smell they may introduce into your interior. Could they be a little 'on the nose'? Ensure that the product you choose does not smell. Many organic fertilisers include bone meal, dried blood, fish emulsion, and other components that give off a noticeable and undesirable odour, with interior plantscapers saying they may be a poor choice in an enclosed indoor space. And be careful that these solutions may not be complete fertilisers, i.e. do not contain a balanced N-P-K ratio critical for plant development. N = Nitrogen, P = Phosphorus and K = Potassium. Plants normally require higher levels of nitrogen and potassium than phosphorus.
Nitrogen (N) is essential in the formation of protein, and protein makes up much of the tissues of most living things. Phosphorus (P) stimulates root growth, helps plants set buds and flowers, and produce seeds. It also helps plants use other nutrients more efficiently and helps turn energy from the sun into usable energy for your plants. Potassium (K) helps plants grow strong stems and keep growing fast. Plants lacking in potassium do not have enough energy to grow properly grow, their roots are not well formed, and they have weak stems, the edges of older plant leaves appear burned, and potassium deficient plants cannot regulate and use water efficiently.
Use controlled-release fertilisers in pots AND water-soluble fertilisers in green walls and hydroponic situations. Plant roots are highly efficient at absorbing nutrients whereas plant leaves can only handle very dilute nutrient solutions otherwise leaves will mark or burn. So only use foliar applications when your plant needs trace elements, e.g. has a deficiency.
Be mindful though that the more you feed your plant, the more it will grow and the more pruning that you may need to undertake.
Tip: Look for new fronds developing at the base of your fern that tell you that now is the time to fertilise. Your fern is in active growth mode!
Remove old, dry fronds below the green ones. Depending on your own preferences of course. I like to let the old fronds stay on for as long as possible to enable any phloem-mobile nutrients, e.g. nitrogen, return to the plant.
Tip: Buy a good pair of secateurs or floral snips and clean them regularly after use with methylated spirits to avoid cross-contamination of disease between plants. Most scissors just don't cut it in this situation (no apologies for the bad pun!). Steel wool soap pads, commonly used to clean grotty dishes in the kitchen, are excellent for cleaning these tools.
PEST & DISEASE MANAGEMENT
Mealybug and other scale insects can be difficult to treat on fern leaves given their delicate nature.
Most scale insects are female and capable of reproducing without males. They become permanently attached to their feeding site and lose their legs, where they feed with their piercing mouth parts. Their protective shells, a defense against predators, makes treatment difficult.
Mealybugs are a type of scale insect and they often hide on underneath of leaves. They look like small bits of cotton. Mealybugs usually feed on the joints between the leaves and the stems or on the leaf veins themselves with their piercing, sucking mouth parts. This causes the leaves to turn yellow and fall from the plant. Some people suggest wiping the mealy bugs with methylated spirits, I would recommend pruning affected branches before they spread. Or you could try applying Eco-neem, a registered organic insecticide that controls a broad range of chewing and sucking insects including mealybug, aphids, mites, fungus gnats in soil plus more. It will also control sooty mould. Alternatively Eco-oil can also control mealybugs, scale and aphids, whilst also attracting beneficial insects (but they have to be in your home for this to happen!). More on that later!
Aphids prefer tender new growth and they love flowers. Most of you though will be growing your indoor plants for their foliage, and not their flowers. Ferns are vascular plants but they do not flower, reproducing instead via spores. So this may be less of a problem for you. They are notorious for spreading disease, e.g. sooty mould. Wash aphids away from your plants or remove them with your fingers or a cotton swab. Apply Eco-neem or rubbing alcohol and use sticky traps to capture them. Prune infected areas.
Fungus gnats look like fruit fly. They breed in moist, overwatered potting mix where they lay their eggs in the top layer. This can damage plant roots. Make sure you water your plants evenly. To control fungus gnat, lay sticky traps or apply Eco-neem. Also, consider replacing the potting mix in which your infected plant is situated, cleaning all traces of this mix from your plant's roots gently with water before potting up in new fungus gnat egg-free mix.
If you want a more natural solution to control pests on your indoor plants, consider the use of beneficial insects. Check out Bugs for Bugs, Biological Services or EcoGrow, all Australian suppliers of beneficial insects. Bugs for Bugs have a handy guide called 'What's your pest?" on their website that tells you which beneficial insects are suitable for use on which plant pest. For example, Cryptolaemus are Australian native ladybird beetles that predate and eat mealybugs.
Consider isolating infected plants whilst you are treating them to avoid further infestation amongst your plants. It is also a good idea to isolate new plants for a time when first bringing them into your home to ensure they do not bring in pests.
Tip: Buy yourself a jeweller's loupe to magnify those little critters on your plants so you can identify them properly. A magnifying glass can also be useful in this situation.
We could go on and on! There is so much more to know about growing ferns indoors. And we haven't even touched exotic fern species. We will leave that for another time.
NB. I do not receive product endorsements from any of the businesses listed above. And I am definitely not an affiliate of Amazon!!! :P
Habitat Plants 2021, Catalogue, January 2021, viewed 11 February 2022, https://habitatplants.com.au/hpwp/wp-content/uploads/Catalogue21-4.pdf
Hanks, Margaret 1996, A Grower's Guide to Ferns, Palms and Climbers, Murdoch Books, Sydney
Plants of Tasmania Nursery 2015, 'Plant list - Ferns', viewed 11 February 2022, https://www.potn.com.au/plant_list_ferns.html
University of Tasmania 2019, Key to Tasmanian Vascular Plants, viewed 11 February 2022, http://www.utas.edu.au/dicotkey/dicotkey/key.htm
Böse, Wolf n.d., Fish Smell by Wolf Böse from the Noun Project, viewed 7 October 2021, https://thenounproject.com/term/fish-smell/462288/
Gemcuts 2021, Jewellers Loupe 10x - 21mm, viewed 18 February 2022, https://www.gemcuts.com.au/jewellers-loupe-10x-21mm
Hampshire, Gail 2014, Scale Bugs on Ivy, 1 April 2014 (CC BY 2.0), viewed 7 October 2021, https://commons.wikimedia.org/wiki/File:Scale_Bugs_on_Ivy_-_Flickr_-_gailhampshire.jpg
Home Hardware 2021, Cyclone Floral Snips, viewed 6 September 2021, https://www.homehardware.com.au/cyclone-floral-snips-6246417
Jordan, Greg 2019a, 'Adiantum aethiopicum', Key to Tasmanian Vascular Plants, University of Tasmania, viewed 18 February 2022, https://www.utas.edu.au/dicotkey/dicotkey/ferns/zAdiantum1.htm,
Jordan, Greg 2019b, 'Asplenium bulbiferum (note the bulbil growing from the leaf blade)', Key to Tasmanian Vascular Plants, University of Tasmania, viewed 18 February 2022,
Jordan, Greg 2019c, 'Blechnum nudum', Key to Tasmanian Vascular Plants, University of Tasmania, viewed 18 February 2022, https://www.utas.edu.au/dicotkey/dicotkey/ferns/zBlechnum_nudum2.htm
Jordan, Greg 2019d, 'Cyathea australis', Key to Tasmanian Vascular Plants, University of Tasmania, viewed 18 February 2022, https://www.utas.edu.au/dicotkey/dicotkey/ferns/zCyathea_aust2.htm
Kittykittymaomao 2020, Newly unfurled monstera deliciosa leaf. The leaf is soft and delicate until it matures., 31 May 2020 (CC BY-SA 4.0), viewed 7 October 2021, https://commons.wikimedia.org/wiki/File:New_Monstera_Deliciosa_Leaf.jpg
Short, David 2016, One of the blighters that have taken a fancy to our orchids. - perh. Pseudococcuslongispinus - červecpaprsčitý, 21 October 2021 (CC BY 2.0), viewed 7 October 2021, https://commons.wikimedia.org/wiki/File:Mealybug_(32636243590).jpg
Sullivan, Jon 2016, aphids, insects, viewed 7 October 2021, https://pixnio.com/fauna-animals/insects-and-bugs/aphids-insects (Jon Sullivan on Pixnio)
Tann. John 2012, Male Dark-winged Fungus Gnat, a species of Sciaridae. Dargo Victoria Australia, September 2012, 15 September 2012 https://commons.wikimedia.org/wiki/File:Dark-winged_Fungus_Gnat_(8009214159).jpg, viewed 7 October 2021, https://commons.wikimedia.org/wiki/File:Dark-winged_Fungus_Gnat_(8009214159).jpg
The Container Connection n.d., ‘CottaPot™ Sub Irrigation Single Wall Planter Exterior’, viewed 18 February, http://containerconnection.com.au/product/cottapot-sub-irrigation-single-wall-exterior/