Ultimate Asparagus Fern Guide

18 Dec 2021

The asparagus fern isn’t what will be served at the dinner table as it’s actually a houseplant. This has bright green needle-like foliage and long stems. It is slightly finicky but with the optimal care, you’ll grow a lush houseplant.

In this article, we will go through all of the necessary care and environmental requirements to grow a thriving asparagus fern.

Main Features

This houseplant isn’t actually a fern at all and instead, it belongs to the Liliaceae family. It is a relative of the Asiatic lily. When it is grown indoors it is a perennial plant and has soft fuzzy but thorny spurs. It is native to South Africa so it is fairly hardy.

Its botanical name is asparagus aethiopicus, but it goes by a few other names too. This houseplant is also known as asparagus grass, foxtail fern, wild asparagus, emerald feather, Sprenger’s asparagus, and lace fern.

It became popular in Europe in 1767 when it was first described by a Swedish botanist named Carl Linnaeus.

Fun fact: It gets one of its nicknames from a well-known botanist; Carl Ludwig Sprenger. He made this houseplant popular across Europe.

Asparagus Fern Types

There are a few different varieties of the asparagus fern, and we’ll describe each one of them below.

  • Asparagus densiflorus ‘meyeri’: It’s also referred to as asparagus ‘foxtail fern’, and it sprouts bushy plumes that look similar to a fox’s tail.
  • Asparagus setaceus: This variation resembles a true fern and is covered in soft, green needle-like layers. It is also called the ‘plumrose’ fern.
  • Asparagus densiflorus ‘sprengeri’: This variation is also known as the ’emerald’ fern due to its brightly colored, arching foliage. It also produces green berries that turn into a bright red color.
  • Asparagus densiflorus ‘sprengeri compacta’: This type of asparagus fern is smaller and produces compact growth with long, arching stems.
  • Asparagus densiflorus ‘nana’: This dwarf fern has jade-green, feathery leaves.

How Big Does It Get?

With great care, you can expect the asparagus fern to grow between 1 to 3 feet (30.5 – 91.4cm) tall and produce a spread of 6 feet (182.9cm).

How Fast Does It Grow?

Depending on the variety and environment, the houseplant’s growth rate is relatively fast. A healthy plant will produce around 6 inches (15.2cm) of extra growth per growing season.

How Long Does It Live?

If optimally cared for and looked after, it will live for around 10 years, much like the Calla lily. Some experts have grown it for up to 15 years too.

Is It Toxic to Cats and Dogs?

The asparagus fern is mildly toxic to both cats and dogs. If it comes into contact with the berries or sap, it may experience allergic dermatitis.

When either of your pets ingests its berries it may suffer from some abdominal issues.

Here’s a list of the possible symptoms a pet may face:

  • Vomiting
  • Diarrhea
  • Cramps

Please seek professional advice from your vet to ensure that you take the right course of action if you suspect that your pet has eaten the berries.

Asparagus Fern Care

In this section, we’re going to fill you in on all of the care that a flourishing emerald fern requires. We’ll cover everything from watering, pruning, and repotting to the environmental requirements.

How Often to Water It

The asparagus aethiopicus is a fairly thirsty houseplant and should be watered 1 to 2 times a week. You don’t want to allow the soil to completely dry out, so make sure that you check the potting mix regularly. Feel the top 2 inches (5cm) of the soil with your finger and if it’s dry, then water it.

You may have to adjust your watering schedule depending on the season and weather. The warmer it is the more water it needs, and the drier the air the more water it requires. When it is winter then you’ll need to water it less frequently.

When watering it, make sure to give it a deep water. Ideally, you should wait for some water to begin trickling through the drainage holes.

Drainage

As the plant requires a decent amount of water and moisture, it needs adequate drainage. You’ll need to plant it in some quick-draining soil and a pot with drainage holes.

Drainage is important as it prevents any water from pooling at the base of the pot, so the roots won’t get enough air. Poor drainage also causes a plant to become waterlogged which leads to root nodule damage.

When to Cut It and How

It’s best to give it a good pruning every 3 years during the springtime. Trimming will encourage healthy growth, and remove leggy and diseased parts of the houseplant.

Follow the simple steps below:

  1.  Cut back the entire plant down to 3 inches (7.5cm) above the soil line (every 3 years).
  2. If you’re only trimming off unhealthy tissue then snip off 2 inches (5cm) below the diseased area.
  3. After pruning, make sure to feed it with a slow-releasing fertilizer.

Top tip: Always sterilize the pruners/shears before use to prevent the spread of disease and bacteria.

Repotting

Asparagus aethiopicus requires transplanting every 2 years during its active growing seasons (spring or summer). It is also necessary to repot the fern when its roots protrude through the drainage holes.

Keep in mind that you don’t want to repot it in a container that is too big. It is best to go up by an inch or 2 (2.5 – 5cm).

Follow the guide below:

  1. Slide it out of its container and dust off some of the remaining soil surrounding the roots.
  2. Fill a new pot with fresh soil and place the houseplant in the center.
  3. Add some extra soil to cover the roots and water it thoroughly.
  4. Position it back in its original home and care for it as you previously did.

Environment

Light Requirements

Asparagus ferns prefer filtered sunlight and partial shade. It can cope in low-lit areas but growth may become very slow and leggy.

The plant can tolerate indirect sun but it should never be placed in full sunshine. It doesn’t do well in bright or direct sun as its leaves will become scorched.

Best Soil

Ideally, you should grow it in some loose, well-draining, and loamy soil. It thrives in an acidic potting mix with a pH level of 6.5 or 6.8. It needs aerated soil to allow for any excess moisture to flow out or be absorbed.

Just like orchids, it loves sphagnum moss or mulch in the potting mixture. You can also throw in a handful of compost to enhance the nutrient density. This houseplant also thrives in potting soil with perlite.

Top tip: Mix together 1 part clay, 2 parts sand, and 2 parts silt to make the perfect potting soil.

Fertilizer

The houseplant prefers a slow-releasing fertilizer or a balanced, water-soluble one. The best type of fertilizer is liquid with an equal amount of potassium, nitrogen, and phosphorous (10-10-10).

During the spring and summertime, you will need to feed a young plant once a week to encourage root growth. A mature houseplant only needs to be fed once a month during its active growing seasons.

Pot Size and Type

Asparagus aethiopicus needs to be planted in a pot that is about 2 to 3 inches (5 – 7.5cm) wider than its rootball. It needs enough space around its root to allow them to grow without becoming root-bound.

A terracotta pot is a perfect container for this houseplant as it prevents root rot. The pot is also heavier so the plant won’t fall over, and it allows excess moisture to evaporate through the porous container.

Temperature Tolerance

This houseplant prospers in temperatures between 53 and 77°F (12 – 25°C). It is important that it isn’t left in temperatures that dip below 50°F (10°C), as it may begin to wither away and stop growing.

Humidity

It is vital that this houseplant is grown in a humid environment. It prefers an area with a humidity level of 40 percent or higher.

Adequate humidity levels will promote lush and healthy growth. You can ensure that the air surrounding the asparagus fern isn’t too dry by misting the plant regularly and placing a humidifier close to it.

Outdoors vs. Indoors

As this plant is native to warmer regions, it can be grown outdoors in USDA hardiness zones of 9 to 11. When it is planted outside or grown in a hanging basket on your patio then you’ll have to keep a few things in mind.

Make sure that the plant only receives partial sunlight especially during the summer. It will need to be misted 3 times a week as it requires more moisture.

The soil will need to be rich and contain plenty of minerals. To ensure that the plant isn’t lacking in any nutrients, you can feed it once a month throughout the year.

Asparagus fern - care, water, light, soil, pot, temperature, fertilizer (infographics)

Does It Bloom?

It is uncommon for the houseplant to bloom indoors. If it does bloom then you can expect tiny white flowers during the summertime.

Depending on the type of plant, it may produce small red or green berries. These may last for around 2 months, and make sure to save the seeds. These can be used to grow an entirely new fern later on.

Once these berries begin to die, it is best to snip them off. This will allow nutrients and energy to be used for new growth.

Fun fact: Male asparagus ferns do not grow any berries.

How to Grow It

Asparagus aethiopicus can be propagated by dividing its tuberous roots, and it can be grown by planting its seeds. You should propagate it during the springtime so that it can sprout new growth before winter.

Unfortunately, as the plant is grown from tuberous roots, its cuttings cannot be propagated.

Asparagus Fern Propagation

You can either propagate the houseplant’s divisions in soil or water. The asparagus fern’s roots will be divided into separate clumps and each can then be repotted in smaller containers.

Additionally, you will need to water it well the day before you plan on dividing it. This way its roots are hydrated and healthy.

Propagating in Soil

When separating the rooting system, make sure that the separate clumps are propagated in fresh and well-draining soil. It will take around 4 weeks until new growth sprouts.

  1. Carefully remove the fern as you don’t want to damage the foliage.
  2. Look for areas of division and slice through the rootball.
  3. You can now gently separate the clumps and ensure that the roots aren’t damaged.
  4. Fill new pots with some potting mix and plant the divisions.
  5. Water it well and place it in filtered sunshine.
  6. Now, you can care for it as you would a mature houseplant.

Propagating in Water

When propagating the divisions in water, you will need to use a clean jar and distilled water. Once it becomes murky then empty it out and refill the jar with clean water.

  1. Slide the houseplant out of its container and examine the rootball for logical areas of division.
  2. Use a sterilized pair of scissors or pruners and cut the rootball into separate clumps. Then you can pull these apart and make sure to prevent any damage to the roots.
  3. Prepare a glass jar with room temperature water and place the division inside.
  4. Find an area where it’ll receive partial sunlight and check the water every couple of days.
  5. After 4 weeks and new root growth has developed then repot it in some soil.
  6. Care for the houseplant as you would an adult plant.

Seed Planting

During the springtime, you can plant the seeds harvested from the berries.

  1. First, you will have to soak the seeds overnight before planting them.
  2. Fill a tray with peat moss and some compost.
  3. Scatter the seeds and sprinkle a thin layer of soil over them.
  4. Mist the seeds and place them over a heat source. The seeds must be kept in soil at 70°F (21°C).
  5. You will also need to place a plastic bag over the tray to lock in the moisture and warmth.
  6. After 2 months the seeds should have germinated and you can repot them when the seedlings are big enough.

How to Revive It

Asparagus aethiopicus are a tad fussy so you may notice that its foliage becomes brown or yellow or the plant begins to collapse. These are caused by improper care but with just a few changes you can revive it.

We’ll tell you what to look out for and how to remedy these issues.

Why Is It Turning Yellow?

There are numerous environmental conditions that may be causing the plant’s foliage to become yellow; a lack of light or exposure to direct sunlight, high temperatures, a lack of humidity, and a fertilizer overdose.

If the plant is a pale yellow color then it is suffering from a lack of sunshine, whereas, if its foliage is bright yellow then it is placed in direct sunlight. You will need to find a new home for it where it can grow in partial shade or filtered sunshine.

The houseplant cannot tolerate extreme temperatures so during the summer you should find a cool area for it. Once the winter chill sets in then find a warmer home for your plant.

Humidity is important for healthy growth so spritz the plant frequently if the air is too dry.

When the emerald fern is overfed then you must flush out the fertilizer salts. You can do this by placing it under a stream of water for about 10 minutes.

Collapsing Plant

When the entire plant begins to collapse, it is suffering from root rot. Root rot is caused by excessive overwatering and affects the entire plant. Its roots will become squishy and black, and its foliage will also soften and discolor.

You can remove the plant from its current container and cut back any unhealthy tissue before transplanting it in dry, fresh soil.

Brown Foliage

If you notice that your poor plant’s leaves have begun to brown, drop or its stems are droopy then you may be under- or overwatering it, and it may be grown in a dry environment.

Simply, adjust the amount of times that you water your plant. You need to ensure that the soil isn’t too dry or soggy. If the air in your home is particularly dry then you should mist it with tepid water.

Falling Over

Sometimes the plant becomes too large for its current container. Once the houseplant has outgrown its pot, it may begin to topple over. All you need to do is repot it in a larger container or find a heavier one.

Final Remarks

This luscious green asparagus fern is a great houseplant that may need some precise care but it is well worth it. You can set up an optimal care routine with the advice provided above, then you’ll be able to watch your plant prosper.

Always be aware of your specific region and adjust the houseplant’s environment accordingly. This may require more misting or watering depending on whether you live in a warm or dry area.

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