Asparagus Fern Plant Profile

Tips for Growing Feathery Ferns Indoors

Asparagus fern

 

ThuTruong / Getty Images

The asparagus fern isn’t exactly a common houseplant, but with its feathery, light foliage, it's quite attractive and can be successfully grown indoors. In warmer regions, the fern can be easily adapted to outdoor culture, where it sometimes grows like a creeper and can even become invasive. Indoors, the key to a robust asparagus fern is to keep the plant bushy and dense so its lace-like foliage forms an attractive mound.

Asparagus fern is a fern in name and appearance only. It is belongs to the family Liliaceae and is a relative of lilies, including tulips, daylilies, amaryillis, and hostas. Asparagus fern has a lot of good qualities, but it comes with some important cautions. In warm, humid climates, asparagus ferns can spread rapidly when planted outdoors. It is considered an invasive species in Florida, Texas, and Hawaii. Asparagus fern is also toxic to humans and pets.

Botanical Name Asparagus aethiopicus
Common Name Asparagus fern
Plant Type Annual, houseplant
Mature Size Up to 2 feet high and 6 feet long
Sun Exposure Indirect light (indoors); part sun (outdoors)
Soil Type Well-drained potting soil
Soil pH 6.5 to 6.8
Bloom Time Summer
Flower Color White; flowers are insignificant
Hardiness Zones 9 to 11
Native Area South Africa

How to Grow Asparagus Fern

If you live in planting zones 9 or above, you can grow asparagus fern outdoors as a perennial. In all other zones, it can be planted as an annual or kept indoors as a houseplant. It's also popular as a container plant, where it is often used as a spiller. You can bring the container inside when the weather turns cold.

Asparagus fern's “leaves” are actually tiny branchlets called cladophylls that are flat and look like leaves. Mature plants become woody and can develop sharp spines on the branches, so take caution while trimming older specimens, and wear gardening gloves if you plan to prune an older plant.

When asparagus fern is content in its location, it can produce small flowers and berries. You can plant these berries to propagate the fern. 

Light

The asparagus fern thrives in dappled shade, although it can be acclimated to more light. Keep it out of direct, bright sunlight.

Soil

Plant asparagus ferns in pots or containers in loose, well-drained potting soil. Outdoors, plant it in rich, well-drained soil that is slightly acidic. It is generally tolerant of less-than-ideal soil conditions.

Water

Keeping an asparagus fern hydrated takes a little effort. This plant thrives on humidity. Indoor growing conditions can often be dry, especially due to winter heat. Mist the plant daily, focusing on the arching stems. If the plant appears to be turning brown and droopy, it likely needs more water. While the asparagus fern can dry out to the point of appearing dead, it likely isn't. Warmer, humid air and daily misting will help revive it. Outdoors, keep asparagus fern well watered to prevent the soil from completely drying out.

Temperature and Humidity

Try to maintain a warm temperature (around 70 degrees Fahrenheit) and not dip below 55 degrees Fahrenheit for too long. If you have a shady porch outside, or a greenhouse, the indoor plants will likely respond with abundant growth over the summer.

Fertilizer

Feed asparagus fern with liquid or water-soluble all-purpose plant food diluted to 1/2 strength. During summer, the plant may need weekly feedings; otherwise, feed monthly.

Repotting

Asparagus ferns don't mind being slightly pot-bound and can go up to two years before repotting. For the most successful repotting, divide the plant into big clumps, and be sure to take multiple underground roots when dividing. Place the divided plants into similar-sized pots to retain the tight growth habit. Asparagus ferns do not need large pots, as they are slow indoor spreaders.

Varieties

  • Asparagus setaceus: Lacy foliage often used in flower arrangements; can grow to 10 feet in height if trained
  • Asparagus densiflorus 'Myeri': Also called foxtail asparagus; dense foliage on upright stems
  • Asparagus densiflorus 'Sprengeri': Popular as a hanging plant, with long dropping stems and a full, almost fluffy form
Asparagus setaceus
Asparagus setaceus. seven75 / Getty Images
Asparagus foxtail
Asparagus foxtail. ThuTruong / Getty Images 
Asparagus sprengeri
Asparagus sprengeri. Sicha69 / Getty Images  

Toxicity

Asparagus fern plants are toxic to humans and cats and dogs. If consumed, the berries of the plant may cause gastrointestinal issues, such as diarrhea, vomiting, and abdominal pain. If the berries come in contact with the skin, they may cause a rash at the point of contact. The foliage of many asparagus ferns can cause skin irritation. If you have children or pets, this is not a good plant to have around, indoors or out.