Plant Sheet: Blue Star Fern (Phlebodium aureum)

* Image sources: All images used in this post are from the author

The Blue Star Fern is a special guest in a houseplant jungle. Depending on where in the world you live, it is certainly not the most common houseplant.

Short Sum-Up: Phlebodium aureum, also called Blue Star Fern, Golden Polypody, or Cabbage Palm Fern, thrives in tropical South and Central America. As an epiphyte, it grows on trees in forest canopies, tolerating lower humidity and favoring bright indirect light. Optimal propagation involves rhizome cutting.

With its beautiful blue hue, it is a unique guest in your home. Learn about the needs of this special guest and where its natural origins lie!

Origin and Natural Habitat of the Blue Star Fern

The Phlebodium aureum, commonly called Blue Star Fern, Golden Polypody, or Cabbage Palm Fern, has its natural habitat in tropical and subtropical regions of South and Central America. It grows beautiful long, multi-lobed fronds of a green-blue, even grey-blue color. In nature, its fronds grow as long as 3 feet (1 m).

In its native habitat, the Blue Star Fern grows as an epiphyte on trees, typically up in the forest canopy but also further down along the tree trunks. Being a fern, it grows from a rhizome that attaches its roots to the tree it is growing on.

If you already have a Phlebodium aureum, you will notice that its rhizome grows mainly above the soil. The roots stay at a rather superficial level in the soil. This comes from its epiphytic lifestyle out in nature.

Interesting fact: Rhizomes are botanically speaking not roots but horizontal stems. Above the ground, the fronds (leaves) of the fern shoot out of the rhizome while below the ground, roots grow downwards from the rhizome. Just as with ‘normal’ stems, only the rhizome lies on the ground instead of growing vertically.

Brighten Up Phlebodium’s Day: Light and Water Requirements

Normally, ferns are the type of houseplants that do better in full shade than most other houseplants. However, the Blue Fern is one of the exceptions. As it grows as an epiphyte up on trees, it is used to indirect light coming through the forest canopy.

It will be happiest with a lot of bright indirect light. Though it can do in half-shade, it won’t grow much and get lots of brown leaf tips. We had one at the office once in quite a shady spot, and I had to chop off fronds that were wilting almost every week. It was a rather sad thing to watch.

As for watering, it needs a similar amount as other ferns. The soil should be kept a little moist but never soggy. They do not like to sit in water. Always check the soil moisture with your finger before watering the plant.

Although it needs more light than a lot of ferns, in terms of humidity it needs less than other ferns and doesn’t react as sensitively to changes. It will do well with an average household humidity of about 50-60 %. This makes it an ideal indoor fern for households where heating is on in winter (though I still recommend using a humidifier).

A Phlebodium’s Guide to Happiness: Care Tips

My first and foremost plea to anyone getting or propagating a Blue Star Fern: Have patience!

Ferns, and here the Blue Star is no exception, are generally slow growers and it takes them time to get used to a new environment. However, once you have found a good spot for the Phlebodium and you just let it be, it produces quite a lot of new fronds.

To exemplify the timeframe of a Phlebodium’s growth: I propagated two pieces of a Blue Star rhizome in January 2021. About two months later, the first tiny new fronds appeared. When I moved about half a year later, I gave the fern to my Dad (a big plant enthusiast himself) with only about 2-4 bigger fronds. For the last three years now, the fern has been in a bright spot below a window and it is now just thriving. It produces long, beautifully colored fronds of up to almost 1.5 feet (30 cm). It has found its perfect home!

It took a newly propagated Phlebodium fern a good three years to get to the size of a plant you can buy in-store. Other houseplants (such as Pothos or Philodendron) grow much faster than this. Nevertheless, the joy it brings to see such a long-cared-for plant thrive is an amazing experience!

A Blue Star Fern grows best if you leave it in the same spot without altering anything about its environment, just letting it be.

In winter, keeping humidity levels constant at around 50-60 % will also be good for your Phlebodium to stay healthy.

How To Propagate the Blue Star Fern

Propagation of Phlebodium aureum is best done by cutting pieces off the rhizome. The best parts of the rhizome are its ‘heads’ which is the tip of the rhizome where it keeps growing. Those parts have younger and fresher cells in them, and more energy stored to grow new fronds. Here’s how to go about it:

  1. I recommend using a sharp knife to cut a piece of at least about 2 inches (5 cm). Shorter pieces might not have enough energy to survive. Also, if you have a big mother plant, take 2-3 pieces. Propagation of a rhizome is not always successful, by taking more than one piece you raise your chances of success.
  2. Now, you just gently press the rhizome cuttings on fresh and moist soil. They should have good contact with the soil but not be buried in it. I used a mix of well-draining soil with sand and some orchid bark in it.
  3. Spray some water on the rhizome every other day to keep the soil moist but there is no need to water the whole pot as the rhizome doesn’t grow any deep roots.
  4. Wait. Just wait. It can take two months for any new tiny fronds to show up. But in the meantime, you might see a change of color in the rhizome itself. I remember that the color of the rhizome became more intense, almost a lucid green-blue, and the tip of the rhizome started growing a bit before the first new frond showed up.
  5. After about two months, the first tiny frond will start unrolling itself slowly.

It is often recommended to leave at least one frond on the piece of rhizome you use for propagation. In my case though, the rhizome part always fell to the side because of the weight of the frond. Hence, I had to cut it off. The propagation still worked, though it might have taken a bit longer. Having a frond on the rhizome is good but it also works without it.

It is a long time to wait for the first signs of new growth. However, if a rhizome doesn’t survive, it is easy to spot because it will wrinkle and dry out. So, if your rhizome doesn’t wrinkle and just stays the same, chances are good that it is rooting and will soon reward your efforts with a first green frond!

Another thing to mention here: The first fronds have very irregular shapes and sizes. Don’t worry about that. Actually, for many plants, it is the case that the immature leaves have a very different look than the mature ones. Once your Blue Fern has produced a few fronds, they will slowly turn into the multi-lobed shape it is known for.

Blue Star Fern Superpowers

The Phlebodium aureum is an air-filtering super-plant, cleansing harmful volatile organic compounds (VOCs) out of the air such as formaldehyde, xylene, and tulol.

This is not an unusual trait for ferns as many of them have immense air and soil filtering capacities. This leads us to another superpower of the fern plant family: Ferns have survived unharmed on this planet for more than 300 million years. They are among the oldest plants ever to have lived on Earth and have once, way before the dinosaurs, ruled the landscapes in big forests of giant ferns.

Through the millennia of surviving earthly volcanic turmoils and much more, they have developed incredible filtering capacities, such as taking in heavy metals such as arsenic or decomposing chemicals such as polycyclic aromatic hydrocarbons (PAHs, chemicals that occur in coal or gasoline) into carbon dioxide and water.

These superpowers are being rediscovered by scientists today in a field called phytoremediation in which plants are used to filter pollutants out of our environment. In a way, these millennia-old plants are now used to set straight what humans have polluted. Good or bad? While that is a matter of opinion, certainly the full capacities of plants such as the Blue Star Fern remain to be discovered.

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