Ferns are some of the most beautiful and diverse plants on the planet with hundreds of different species available, and many people consider them to be shade-loving plants. While this may be true, there are also ferns that thrive in full sun locations, and others, ilke the blue star fern, do wonderfully in indoor environments.
Along with growing a host of ferns in your garden outside, you can grow this warm-climate fern species as a houseplant inside. This quick article will break down how to set up the perfect growing conditions to get a thriving and stunning blue star fern.
The blue star fern can grow rather large, but you can prune it to help it maintain a more desirable, tidy shape. Blue Star Fern by Forest and Kim Starr / CC BY 2.0
Introducing the Blue Star Fern
You may assume that the blue star fern isn’t anything but a fairly simple plant with feather-like leaves, but this is far from the truth. Ferns are actually some of the oldest living plants in the world, and they first evolved hundreds of millions of years ago while still thriving today. Unlike many flowering plants, ferns use spores to reproduce instead of seeds. This brings about a very complex lifecycle.
The foliage structure’s diversity may also be a surprise. In the fern world, the leaves are what you would call fronds. Many people envision feather-like, green fronds when someone mentions the word “fern”, but there are several different arrays when it comes to colors and frond structures. The blue star fern is actually a great example of this.
This fern species comes with a grayish-blue coloring on the fronds, and they have a very irregular, deeply lobed shape. When the plant is very young, the new frond growth is very uneven when it comes to shape and size, and they grow from the base of the plant in a very random pattern.
When the plant starts to mature, the blue star fern develops medium or large fronds that are more uniform looking with a consistent structure. If you look at the fronds very closely, you’ll notice that they have small hairlike structures covering them. There are few pests that bother the blue star fern, and this reduces your maintenance needs.
Blue Star Fern Overview
|Diseases and Pests:||Less prone to pest issues and diseases are linked to too much water.|
|Fertilizer:||Lower fertilizer needed. Fertilize every two or three months with a balanced fertilizer and cut back in the winter.|
|Flowering:||Non-flowering species, but produces dual rows of orange spores on the undersides of the leaves.|
|Humidity:||Average to high, but it’s very tolerant low low humidity levels|
|Lighting:||Indirect but bright. It can adapt to lower lights, but won’t tolerate direct light.|
|Origin:||South and Central America|
|Propagation:||Division using the rhizome is the best option, but you can propagate from spores too.|
|Pruning:||Prune to remove damaged or dead leaves and to keep the desired shape.|
|Repotting:||Sensitive to repotting so only do so if the plant is root bound|
|Scientific Name:||Phlebodium aureum|
|Soil:||Epiphytic orchid mix is desired, but it can tolerate any well-draining mix as long as you don’t water it too much.|
|Temperature:||57°F to 81°F (14°C to 27°C) Not cold-hardy|
|Toxicity:||Non-toxic to animals or humans|
|Watering:||Keep the soil consistently moist by thoroughly watering it once the surface of the soil dries out. Ensure it has great drainage.|
Blue Star Fern – Optimal Growth Conditions
You want to set your blue star fern up for success when you grow it inside, so you have to take note of the plant’s preferred environment and growth conditions to do so. The following will give you a quick outline of the most important parts to remember.
Your blue star fern will get the nutrients it needs to grow from the new potting soil for a minimum of six to eight months after you plant it. Once this time goes, the potting soil’s nutrients will be depleted, and it’s now time to fertilize it. You can do so by using a houseplant-specific liquid or granular fertilizer. You want to apply it in early spring through the fall months as this is the blue star fern’s prime growing season. Mix liquid fertilizers with water to dilute it to half of the strength the manufacturer recommends.
If you choose to use a granular fertilizer, you’ll sprinkle ½ to 1 teaspoon on the top of your plant’s soil every six to eight weeks. Organic fertilizers are preferred to those with synthetic chemicals, but this is completely up to you. Don’t fertilize your blue star fern during the winter months when it’s not growing. This will lead to brown or burned roots.
Contrary to popular belief, adding more fertilizer to your blue star fern won’t make it grow faster, unlike most other plants. It can be detrimental to your fern because the roots are very sensitive to build up in the soil.
Ferns like humidity, and this shouldn’t be a big surprise to you. However, higher humidity levels aren’t required to keep this plant happy and thriving. It can actually adpart to the average indoor humidity levels because proper watering routines make up for the humidity difference. However, if the humidity is below 40%, this could be problematic for your blue star fern, and you may want to use the following to boost the humidity:
- Grouping Plants – Putting your plants in a group (especially tropical plants) will raise the humidity levels up a bit through mutual transpiration. It’s better to group the blue star fern with plants that love moisture to get the best results with this method.
- Soil Reservoirs – Put seashells on the surface of the soil in your container and fill them with water. This will raise the humidity levels a small amount, and it’s not as distracting visually as having a water tray.
- Water Trays – Fill a tray with pebbles and water to get a low-tech, easy way to increase the relative humidity around your blue star fern. You can set the plant’s container on this tray as long as the pebbles don’t allow it to sit right in the water.
Because the blue star fern will attach to trees or other forest plants as it grows, this blocks out a lot of light due to the tree canopies. In turn, it doesn’t need a huge amount of light to be happy, but it does appreciate higher light amounts. Anything short of putting the blue star fern in direct sunlight should be okay. This is one of the unique characteristics that sets this plant apart from other ferns as they don’t like any sun.
Since this plant is an epiphyte and not terrestrial like you’ll find many other types of ferns, you don’t want to stick it in potting soil. You want to get something that is much looser than your typical potting soil. Since the blue star ferns love a more moist environment but can’t deal with waterlogged soil, you want a well-draining medium. You’ll have a lot of luck with large and smaller pieces of crushed wood. If you don’t have any available, a loose orchid mix will work as more orchids are epiphytic too.
When you’re trying to figure out the temperature range, the blue star fern isn’t terribly picky. Room temperature is usually fine for them. During the winter, don’t allow it to get too chilly, and frost is something you should avoid to ensure that it doesn’t cause damage or kill your plant.
What this plant is picky about is water, and it has a very limited tolerance for soil that dries out. Since it’s a tree-living epiphyte, it likes slight, steady moisture without overwhelming it. The main thing to do is avoid soggy soil, and the rhizome is very vulnerable to rotting if it’s too wet. A few watering tips to get you off to a strong start include:
- Allow the surface of the growing medium to dry out to the touch before you water it again. You should allow the top inch to dry out, but don’t let it dry out further.
- Flush the soil each time you water it to avoid evaporated residue from building up. All you have to do is allow the extra water to run through the soil and out of the drainage holes.
- No matter which watering method you use, it’s essential that you let it drain thoroughly. If you have a tray below it to catch the water, check it after the plant finishes draining and empty it.
- This fern is very sensitive to salt or other fertilizer residue in the planting medium, including chemicals and minerals like chloramine. Try to use distilled or filtered water.
- Try not to get the blue star fern’s foliage wet when you water, and don’t water the crown. Some people water the sides of the pot when they have the plant outside, but this is messy. All you have to do is set up a basin and set the pot in it until the growing medium is soaked through.
- Use room temperature water so you don’t accidentally chill the plant’s roots.
- When it’s time to water the blue star fern, do so thoroughly by saturating the soil and allowing the excess to drain.
When you water your blue star fern, make sure that you’re not splashing it on the crown or fronds because this makes it much easier for diseases to take hold.
Dividing and Repotting the Blue Star Fern
Every few years, it’s a good idea to repot your blue star fern when it becomes rootbound in the current pot. When the rhizomes on this plant start to push against the side of the container or the plant dries out very fast between watering sessions, it’s time to divide it and repot it or use spores to propagate a new plant if your old one hasn’t outgrown the current pot.
To do this, you’ll carefully remove your plant from the pot. Using sharp, clean tools, cut your blue star fern into two or more pieces. Each portion should come with a root system attached to ensure that it grows. You will have to cut though some rhizomes during this process, but you shouldn’t worry about it too much. This won’t injure them in a lasting way, and they’ll bounce back nicely. Some people like to use their hands to crack the root ball apart instead of cutting it with shears.
Once you make the divisions, you should loosen up the roots with your fingers and plant them into their own pots with a loose soil mix. Keep them at the same depth the original plant was, and water it well to help it settle. You won’t fertilize it for two months after you repot it as the tender new roots will be very prone to damage by fertilizer salts.
You can also use sports to propagate your blue star fern, and you’ll need the following supplies to pull it off:
- Chlorine bleach
- Clean paper towels
- Compressed peat pellets
- Fern frond with sporangia (it’ll have orange on the back of the fronds)
- High quality vermiculite or potting soil
- Kettle of boiling water, preferably filtered or distilled
- Larger glass bowl
- Rubber band
- Small glass container
- Small piece of plastic wrap
- White paper sheets and a heavy book
1. Collect the Spores
With every fern, the exact time to collect the spores will vary. Generally speaking, you’ll be looking for black or very dark brown raised bumps on the undersides of your blue star fern’s fronds. You may also see dedicated fertilizer fronds that aren’t green, but they’re black or dark brown. Some species have green or golden coloring too. When they look ripe, you’ll cut the frond off the plant and lay it on your white sheet of paper. Cover the paper with a second piece of paper and put the heavy book over it to stop exposure to air movement and stop the frond from moving.
During the next few days, you’ll see gold, green, or brown powder collecting under the frond on the sheet of paper. These are the spores. If it doesn’t release any spores, you could have collected the frond slightly early or too late. You can try collecting your fronds at different points during the year or at different developmental stages to figure out which is best.
The spores are on the underside of the frond, and they can be a range of colors, depending on your cultivar.
2. Prepare Your Peat Pellet
The next step is to peel the netting back from the center of your peat pellet and put the compressed pellet into a glass container that you sterilized. Next, pour in boiling water from your kettle. The hot water causes the compacted pellet to expand and rehydrate, and this will sterilize the soil.
You can also put a layer of moist but not saturated vermiculite or potting soil in the bottom of the container instead. You won’t want to use soil from the garden as it has far too many weed seeds and pathogens in it. You can then microwave your container of soil for a few minutes to get the heat to sterilize it. If you do, cover the container with plastic wrap and give it a few hours to cool down.
3. Sow the Spores
Once the peat has expanded and cooled back down, you should check and see if there is standing water. Peel back a corner of the plastic wrap and dump any water out. Transfer your blue star fern spores to a sharply folded, clean piece of paper. When you’re ready, peel back the plastic again and tap the paper to sprinkle the spores on top of your peat pellet.
4. Cover the Container
Immediately following adding the spores, cover the container with plastic and secure it in place using a rubber band. Put it where it’ll get indirect light, or even in a spot where it gets more artificial lighting. The sealed container will mimic a greenhouse and overheat if the direct light hits it. If you have grow lights, those will work nicely.
5. Keep the Spores Moist at All Times
The mini greenhouse you set up should stay moist enough, and you want to see light condensation on the inside. If you notice it drying out, boil water, cover it and let it cool down, and peel back a corner of the plastic and pour a small amount inside. Immediately recover the jar. After a month, you should start to see growth. Gently tap on your plastic cover every few days to knock some of the condensation onto the developing plant to encourage fertilization.
6. Transplant Your Young Ferns
You should see tiny fronds starting to stick up after roughly a month if you were successful. These are your baby blue star ferns. Once they’re large enough to safely handle, you want to transplant them out into individual containers and cover them with plastic wrap. Allow them to sit for a few weeks, and then you should poke a few pin holes into the plastic wrap. Every three to five days, add more holes in the plastic. Your baby ferns should be ready to remove the plastic after a few weeks.
Keep upgrading the container size as the blue star ferns grow. Once they reach six months to a year old, they should be big enough to plant out in the garden or in containers to share with your friends. Every fern you grow from spores will be genetically different, so take note of the differences. Some will grow much more quickly, and some will have various hues of blue.
Pruning the Blue Star Fern
Pruning your plant is an essential part of keeping it healthy. You’ll do so to remove dead or damaged foliage or errant stems from the plant and allow it to conserve its energy for new growth. This also helps prevent diseases and pests from taking hold. You can’t prune them to promote specific growth, but you can prune them to help them maintain a certain shape and size.
Remove any dead foliage you spot so it doesn’t invite disease or pests. Damaged leaves won’t repair themselves, so you should remove it as you notice it declining. You’ll snip the thin stems to prune the blue star fern, and you should have sterile scissors to do so. Wiping them with rubbing alcohol will sterilize them.
Pruning the blue star fern won’t stunt the plant’s growth, but it can help you maintain a nice shape.
Blue Star Fern Care Tips
Even though keeping this fern alive and thriving isn’t a huge project, it’s important that you keep the following tips and tricks in mind to keep your plant as happy as possible. A few care tips include:
- Browning can impact more than just the frond tips, and it has links to insufficient soil moisture or humidity levels.
- Brown tips on your blue star fern’s fronds are usually caused by the soil getting loaded with minerals, salts, or other chemicals, or from tap water usage.
- Ferns are slightly fragile plants, and they go into shock very easily from rough treatment or repotting. It’s common for your plant to lose a few fronds and need time to recover.
- Great air circulation is essential to keeping your plant healthy.
- If the blue star fern goes into shock, you should put it in a humid, warm spot with adequate lighting. It can help to tent your plant in a clear plastic to raise the humidity levels. Once you see new growth, you can slowly acclimate your plant back into the normal growing environments.
- If the foliage is starting to turn brown or purple, water on the crown or wet rhizomes are usually to blame.
- Look to the heart of your blue star fern to see new frond growth.
- To maximize growth, give your fern adequate light. You can’t force them to grow faster by adding extra fertilizer or repotting them a lot.
Common Pests And Diseases for the Blue Star Fern
Even though this plant has fewer pest or disease issues, it’s not completely free of them. It is less susceptible than many fern types to having problems with spider mites, aphids, scale, thripe, and mealybugs though. The main problem is that these pests can hide in the fuzzy coating of the plant’s rhizome for protection, and this makes getting rid of them more challenging. Light horticultural oils and insecticidal soap can help, but they have to come into contact with the pests.
- HappyDIYHome Note – Seeing white spots on the rhizomes and foliage is very common for this plant. You shouldn’t worry about it unless you spot other signs of an infestation.
Keep this fern a good distance away from any infested plants. If you have issues with pests, you want to isolate the plant as quickly as you can to prevent them from spreading further. You will need to repeat your chosen treatment every four to six days until you eradicate the pests. Harsher pesticides are an absolute last resort.
Most Blue Star Fern Diseases Are Related to Moisture
The most common diseases your blue star fern will face are all triggered by too much moisture. This is exactly why you have to be so careful not to overwater it. For the following three diseases, prevention is usually the best, and sometimes the only way to save your plant. They are:
- Mildews – Powdery and rust mildew are very common and triggered by excess moisture. The best ways to prevent them are to keep the fronds dry and ensure it has healthy air circulation.
- Root Rot – This is the single most common and serious disease your blue star fern can face, and it can start taking hold after a few short hours in soggy soil. It’s much more common with heavy soils.
- Southern Blight – Finally, this fatal root fungus loves moist, warm conditions that the blue star fern also needs. There are currently no effective fungicides available to home gardeners, and the best preventions are sterilizing your potting medium and tools before it comes into contact with the plant.
The blue star fern is a stunning, bushy house plant that doesn’t require a huge amount of care to thrive. You can use this quick guide as a reference to ensure you get the best growing conditions to keep this plant healthy and growing for years, both indoors and outdoors.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.