Asparagus densiflorus Sprengeri (Emerald Fern) Care Indoors, Propagation and Problems

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Asparagus densiflorus Sprengeri (Emerald Fern) thrives in medium to bright indirect light, average warmth and humidity, and moderately moist, rich, well-drained soils coupled with weekly feeding in the growing season.

Asparagus densiflorus Sprengeri also called Sprenger's Asparagus or Sprenger's Fern is one of the ornamental Asparagus ferns whose arching stems are sparsely covered with clusters of soft, needle-like foliage.

Sprenger's Asparagus is an evergreen, fern-like plant with trailing stems which bear bright green 'leaves' hence the common name 'Emerald Fern'. The 'leaves' are really needle-like branches.

Though commonly called a fern, Emerald Fern is not a True Fern as it is much easier to grow than true ferns. It adapts well to wide variations in light, heat and watering frequency.

Asparagus densiflorus Sprengeri is perfect for a hanging basket, desktop, plant shelf or pedestal where the stems can cascade downwards beautifully. The Fern can also be grown as an outdoor container plant.

The name 'Sprenger's Fern' is attributed to Carl Ludwig Sprenger who made it popular in Europe as an ornamental Plant.

Botanical name: Asparagus densiflorus 'Sprengeri'
Synonym: Asparagus sprengeri
Family: Asparagaceae
Sufamily: Asparagoideae
Common names: Emerald Fern, Sprenger's Asparagus, Sprenger's Fern

Origin

Asparagus densiflorus Sprengeri is native to the Cape Provinces and the Northern Provinces of South Africa where it grows in rocky slopes and coastal scrub in dry areas.

Flower

When provided with the right growing conditions, Emerald Fern may produce clusters of small white flowers which are followed by bright red berries.

Size

Emerald Fern habit can be dense and compact to wide-spreading with the stems growing up to 3 feet long. This wide-spreading nature of this fern makes it perfect for a hanging basket.

Is Asparagus densiflorus Sprengeri poisonous?

Yes, Asparagus densiflorus Sprengeri like other Asparagus Ferns is toxic to humans and pets as indicated by ASPCA. If the berries are ingested, they can cause vomiting, diarrhea and abdominal pain. If handled with bare hands, the berries can cause contact dermatitis.

The foliage of mature plant can develop sharp spines on the branches which can cause skin irritation if handled with bare hands. Therefore, always wear gloves when handling Sprenger's Asparagus.

Invasiveness

As outlined by Mark Tancig (University of Florida), Asparagus Ferns have been found to be invasive in some regions. Avoid growing Asparagus Ferns in the ground and dispose them by burning as they grow vigorously, spreading across and scrambling up other plants.

Where to Buy

Would you like to add Emerald Fern to your collection? You can acquire these ferns from Etsy (Link to Etsy).

Asparagus densiflorus Sprengeri Care Indoors

To care for Emerald Fern indoors, give it medium to bright indirect light, warmth of 18-28⁰C, humidity of 60-70% and moderately moist, fertile, well-drained soils coupled with weekly feeding during the growing season.

Sprenger's Asparagus requires regular pruning to keep it neat and tidy as well as minimize pest and disease infestations. It only requires repotting when pot-bound. Keep reading for more on these growing conditions and how to provide them.

Watering

Water Emerald Fern thoroughly in spring and summer while allowing the top 2-3 inches of soil to dry out between waterings. Keep the soil moderately moist and avoid overwatering to prevent rotting, drooping, yellowing and leaf loss.

Cut down on watering in fall and winter as growth is reduced at this time. Do not let the soil dry out completely to prevent wilting, drooping, yellowing and leaf drop.

Use water that is at room temperature to prevent cold shock which can cause slowed growth and leaf loss. Only use chlorine-free water to prevent browing of leaf edges.

Occasionally water from the bottom to ensure that the soilball is thoroughly wetted. Take care not to wet the foliage to minimize fungal diseases.

Make sure the soil is free-draining and the pot has a drainage hole to prevent waterlogging which can lead to root-rot and eventual death of the fern. Always empty the saucer when done watering to prevent soil sogginess.

Light Requirements

Emerald Fern grows best in medium to bright light; position infront of a bright, sunless window. Keep it away from direct sunlight or use a sheer curtain to filter the sunrays to prevent scorching of the leaves.

If the fern does not receive adequate light the leaves will lose their color, turning yellowish and the plant may become leggy. If the natural lighting is not adequate, use full spectrum grow lights to increase it.

Give the pot a 90⁰ turn every month to ensure that the plant receives light on all sides for an even growth.

Temperature & Humidity

Emerald Fern prefers a warmth of 18-28⁰C. Though it can adapt to a wide range of temperatures, constantly high or low temperatures will result in stunted growth, drooping, yellowing and leaf loss.

Therefore, keep the plant away from sources of drafts like open doors, drafty windows, AC units, hot air vents among others to prevent temperature flactuations.

Asparagus densiflorus Sprengeri has no need for extra humidity; a humidity of 50-60% is adequate for this fern. Very low humidity (dry air) will result in brown leaf tips and leaf drop.

To elevate humidity, especially when temperatures are very high in winter, set the pot on a wet pebble tray, or place the fern in a well-lit bathroom. Ensure proper air circulation to reduce fungal diseases.

Potting Soil

The best potting soil for Emerald Fern should be rich in organic matter, well-aerated and free-draining to prevent sogginess. A mix of 50% potting soil, 30% perlite, and 20% orchid bark is good for this fern.

Fertilizer

Feed Emerald Fern with a balanced, liquid fertilizer once a week in spring and summer to encourage a lush growth. Withhold feeding in fall and winter to prevent fertilizer burn as growth is minimal at this time.

Repotting

Repot Emerald Fern at the beginning of the growing season, only when it becomes root-bound, that is, when the roots begin to grow through the drainage holes.

Use a pot 1 size larger that has a drainage hole and well-draining soil to avoid sogginess which can lead to root-rot. You may divide the large ferns during repotting to propagate new plants. Take a look at these pots with drainage holes on Amazon.

Pruning

Pruning Emerald Fern requires cutting back of the old stems to make room for new growth. Trim the dead leaves and branches to keep the Sprenger's Asparagus neat and tidy and also discourage pest and disease infestations.

Emerald Fern Propagation

Emerald Fern (Asparagus densiflorus Sprengeri) is propagated at the beginning of the growing season from seeds or by plant division. The easiest method of propagation is by plant division. Learn how to propagate Asparagus Ferns in 3 easy ways.

Asparagus densiflorus Sprengeri Problems

Emerald Fern problems are yellowing and dropping leaves, plant death, diseases and pests among others. Keep reading for more on these problems and how to fix them.

Yellowing and dropping leaves

Yellowing and dropping leaves on Emerald Fern are caused by too little light, inconsistent watering, soggy soil, dry air, temperature stress, direct sunlight, pests, diseases among others.

Check out these 12 Reasons Why Asparagus Fern Leaves are Yellowing and Dropping.

Plant dying

Emerald Fern is dying due to root-rot which is promoted by soggy soil. The thick, tuberous roots will rot in soggy soil, causing the plant to die if corrective measures are not taken in time.

How to fix it

1. Carefully slip the fern out of its pot and inspect the roots.


2. Trim the brown-black, mushy roots and treat the healthy roots with a copper-based fungicidal solution as per the instructions on the label.


3. Disinfect the pot with the fungicidal solution or use a fresh pot to repot the plant.


4. Use a pot with a drainage hole and well-draining soil.


5. Do not water the plant immediately; keep it dry for 5-7 days before you resume watering.


6. Lessen watering in fall and winter as growth is slowed at this time; keep the soil slightly moist.

Diseases

Emerald Fern is also prone to crown and stem-rot disease which is common in overwet, poorly ventilated conditions. The disease is characterized by a rotting plant base, yellowing and shrivelled leaves.

The disease is difficult to treat. If it has spread, the plant cannot be saved and it should be discarded together with its pot and soil. If caught early, the disease can be treated as follows.

How to treat early infestation

1. Cut and discard or burn the diseased tissue.


2. Treat the affected plant with neem oil as indicated by the manufacturer.


3. Keep the soil on the drier side; withhold watering for 10-14 days.


4. Confirm that the soil is free-draining and the pot has a drainage hole.


5. Maintain good airflow to discourage the disease infestation.


6. Place the plant away from cold drafts to maintain an average warmth.

Pests

Common pests on Emerald Fern are spider mites, aphids, mealybugs and whiteflies whose infestation is enhanced by either underwatering or dry air.

How to fix it

1. Regularly inspect the plant for these pests and take timely control measures.


2. Seperate the infested plant to reduce spread to other plants and treat it with neem oil or insecticidal soap as per the manufacturers' instructions.


3. Clean the leaves by damp-wiping with a soft cloth to discourage the pests.


4. Keep the plant well pruned to reduce the hiding and breeding places for these pests.


5. Set the plant on a wet pebble tray to increase humidity as it discourages the pests.

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