The name ‘Asparagus Fern’ is quite misleading, as this plant is neither an asparagus plant nor a fern. In fact, it is quite the opposite of asparagus, as asparagus is obviously edible, while the asparagus fern is highly toxic. It is poisonous to both humans and most household pets, and if ingested will cause vomiting, diarrhea, and tummy pain. The plant can also cause skin irritation, so it should be handled with care and kept away from curious children.
The asparagus fern also fails to fit into the category of ‘fern,’ though it was likely named as such because the feathery foliage does resemble that of a fern. This is a fairly uncommon houseplant and actually is categorized as a weed, but it works well indoors in containers or hanging pots and is very hardy. It can also be grown outside as an annual or perennial, depending on the climate. It has a spreading habit, which makes it suitable for ground coverage, though in some regions, it is listed as an invasive plant, such as in Hawaii, Florida, and Texas (Royal Horticultural Society).
Asparagus Fern Overview
|Scientific Name||Asparagus aethiopicus|
|Type||Evergreen houseplant or shrub|
|Common Names||Asparagus fern, Feathery asparagus|
|Height||Up to 6 feet|
|Toxicity||Toxic to people and pets|
|Light||Bright indirect light, partial shade|
|Watering||Moist well-draining soil|
This variety of asparagus fern has a very delicate look, with fine feathery foliage. Although the plant has a soft appearance that almost begs to be stroked, it actually features lots of tiny spikes, and so, should be handled with care. It can be trained to have a climbing or trailing habit and can grow to lengths of 10 feet. The bright green lacy foliage is popular in bouquets.
Asparagus densiflorus sprengeri
This asparagus fern has an upright growth habit when young, but the stems begin to arch when longer and heavier. As it ages and grows, the plant forms a draping mass of feathery foliage, which works well in indoor hanging baskets or looks equally good tumbling over the side of a shelf. It heavily relies on humidity to thrive and will need regular misting. The foliage has more of a pine needle look than other varieties of asparagus fern, in an attractive bright green shade.
Asparagus densiflorus mysersii
This variety of asparagus fern has dense foliage that forms a fluffy tail like appearance, giving it the common name of ‘foxtail’ or ‘cats tail.’ It can be grown outdoors and is hardy to temperature lows of 25 ºF (Missouri Botanical Garden).
Caring for Your Asparagus Fern
The asparagus fern likes to be kept in moderately moist soil. It doesn’t like to become completely dried out, but it also does not like soggy soil, so you will need to aim for a balance somewhere between the two. When kept as a houseplant, water the plant thoroughly and then allow the top inch or two of the soil to dry out before you water it again.
The frequency with which you need to water the plant will depend on the season and how much light the plant is getting, so water it according to its conditions rather than on any schedule. When kept outside, the plant is more likely to be susceptible to drying out, especially in hot summers, so water it regularly to keep the soil from drying out.
Whether planted indoors or outdoors, the asparagus fern needs a well-draining soil to avoid waterlogged conditions. It also prefers acidic soil but is quite tolerant of a range of soil types.
This plant enjoys bright indirect sunlight or dappled light. When grown indoors, it needs a good amount of bright light in order to thrive but should be kept out of direct sunlight where it will scorch. It can be acclimated to more light, but you should do this gradually.
When grown outside, position this plant in an area where it is semi-shaded. It will do well in a spot that is protected by the shade of other nearby shrubs and trees but still gets some light coming through at different times of the day. If you do decide to plant the asparagus fern in a sunny position, ensure that it is shaded during the afternoon when the sun is at its strongest. The tiny needles of the fern are susceptible to drying out or being burnt by too much light,
This plant is hardy to USDA zones 9 to 11. When grown outdoors, it thrives in warm climates and will respond especially well to greenhouse conditions. The asparagus fern is ideally suited to life as a houseplant as it enjoys temperatures in the range of 70 ºF, which is typically the temperature that many homes are kept at.
In the case of this plant, you can be confident that if you are comfortable with the temperature of your home, then your asparagus fern will be comfortable too. It can tolerate drops in temperature as low as 50 ºF, but it will not respond well to consistently low temperatures. Be sure to keep it in warmer rooms in the house during winter and not leave it in disused rooms where the heating isn’t turned on.
This plant thrives in moist air, so it’s essential that it lives in a humid environment. The plant will appreciate being grown in an outdoor climate, which is naturally humid, but if grown indoors as a houseplant, you will need to artificially create humidity, especially during the winter, when air typically becomes very dry due to indoor heating systems.
There are several ways you can increase the humidity around the plant, and probably the most popular method among plant lovers is to mist the plant with a water spray. The asparagus fern will need a daily misting to be kept happy, and while some plant owners enjoy doing this, others may find it too laborious. In this instance, you may prefer to use an electric humidifier that you can simply plug in and forget about until it needs refilling. An electric humidifier disperses tiny particles of water into the air to increase humidity in the whole room.
A cheaper way to achieve higher humidity for your plant is to use a pebble tray. Simply sit the plant on a tray of pebbles that are bathed in water. As the water evaporates from the pebbles, the air around the plant will become moister. Always be sure that the water level sits lower than the tallest pebbles to ensure water does not come into contact with the base of your plant pot; otherwise, the water may be absorbed by the soil through the drainage holes, and your plant may inadvertently become overwatered. You will need to keep track of the water level in your pebble tray, making sure it gets refilled frequently to ensure the humidity level remains consistent.
If your asparagus fern begins to droop or look as though it is drying out, it can usually be revived with a good misting. If you keep the asparagus fern outside in a greenhouse, it will respond well to the high humidity provided in this type of environment, and you will likely witness an abundance of growth.
This plant can be propagated by division, which is best done during repotting. When your plant becomes too big for its pot, you can remove it from the pot and separate the plant into two or more new plants. The roots of the plant will likely be heavily intertwined, and it can seem quite daunting, but the roots are robust and will respond well to being divided.
Try to gently ease the root ball apart with your fingers, and use a sharp knife to cut apart any remaining roots that you are unable to separate by hand. Set the newly divided plants into fresh potting soil in new pots and water them generously to help them settle, then continue care as normal.
Asparagus ferns respond well to being root bound and should not need repotting very frequently. When young, they should be repotted every two years, but as they get older, they will be able to go longer between repotting.
When the root ball of your asparagus fern feels like it is bulging out of the pot, you know it's time to repot it. Ease it out of its pot and place it into a new pot just one or two sizes bigger. Press new potting soil around the edges of the root ball, ensuring the base of the plant is at the same height as it was in its previous pot.
This plant is a heavy feeder, especially during the summer, when it tends to undergo periods of rapid growth. To sustain all of the new growth, the asparagus fern may need to be fed as frequently as every week or at a minimum of once a month. Use an all-purpose liquid fertilizer diluted to half of its recommended strength. Cease feeding during fall and winter, then begin again when spring rolls around.
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