Asparagus densiflorus, also known as plume asparagus, is a variable evergreen perennial plant that is closely related to the vegetable asparagus. Other common names for this plant are asparagus fern and foxtail fern. Although it is native to the region stretching from Mozambique to South Africa, it is now widely cultivated elsewhere in the world. This perennial evergreen with ferny, bright green foliage is frequently grown indoors or as an outdoor decorative plant.
I. Appearance and Characteristics
Asparagus densiflorus (among several species colloquially called asparagus ferns; no relation to actual ferns), or the foxtail fern (asparagus) or plume fern, is a variable, evergreen-perennial plant related to cultivated, edible asparagus.
It is native to southern Africa, from Mozambique to South Africa, but is widely cultivated.
Asparagus fern reaches heights of between 12 and 40 inches. Depending on the variety, growth is more or less upright, and depending on the length of the shoots, it is expansive and arches downwards. The roots are thick and bulbous.
Strictly speaking, the Asparagus fern does not have leaves, but modified side shoots (phylloclades). The “true” leaves of the Asparagus fern have developed into thorns. With optimal conditions and good care, Asparagus densiflorus forms tiny white flowers in summer. However, it is not a reliable bloomer.
After flowering, small red berries appear on the plant in late summer. Note: Regardless of the species or variety, all Asparagus fern berries are highly poisonous and unfit for human consumption!
As it cannot tolerate frost, in temperate regions A.densiflorus is usually grown under glass. Numerous cultivars have been developed, of which the compact form ‘Myersii’ has gained the Royal Horticultural Society’s Award of Garden Merit. Its dense 50 cm plumes of foliage are especially valued in flower arranging.
II. How to Grow and Care
Sunlight
The asparagus fern thrives in dappled shade, although it can be acclimated to more light. Keep it out of direct, bright sunlight, which can scorch the foliage.
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 or a greenhouse, the indoor plants will likely respond with abundant growth over the summer. Avoid sudden changes in temperatures, which can cause the cladodes to drop.
Watering
Keeping an asparagus fern hydrated takes a little effort, as this plant thrives on humidity. Indoor growing conditions can often be too dry, especially during the winter heating season. Mist the plant daily, focusing on the arching stems. If the plant appears to be turning brown and droopy, it likely needs more water.
Keep soil moist, and water when the top inch of soil feels dry to the touch. Warmer, humid air, and daily misting will help it thrive. Outdoors, keep asparagus fern well-watered to prevent the soil from completely drying out.
Soil
Plant asparagus ferns in pots or containers in moist, loose, well-drained potting soil. Outdoors, plant it in rich, well-drained soil that is slightly acidic. It prefers rich soil to thrive. Make sure containers have drainage holes.
Fertilizing
Feed asparagus fern with liquid or water-soluble all-purpose plant food diluted to half strength. During summer, container plants may need weekly feedings; otherwise, feed monthly.
Pruning
The low-maintenance houseplant does not actually need pruning. But you can removed withered fronds. As already mentioned, asparagus fern reacts very sensitively to dry conditions. If you forget to water your Asparagus fern, don’t abandon it right away. It’s best to cut it back drastically to just above the soil, put it in a warm spot indoors with a slightly higher humidity and with a little luck, the plant will produce new growth.
Propagation
While this plant can be propagated by planting the seeds found in the berries, the easier and faster way is to dig up and divide the tuberous roots:
- In spring, dig up the entire plant (or remove it from its pot), using a trowel or shovel. Make sure to wear gloves to protect yourself from the sharp spikes.
- Divide the root clump into sections with a trowel or knife, making sure each section includes a root section, as well as a portion of the crown with growing shoots.
- Replant the pieces into individual pots or their own garden locations. It is best to keep the plant shaded until new growth begins.
How to Grow from Seed
Asparagus fern seeds can be found inside the small red berries produced by mature plants. When the berries are fully ripe, mash them and strain out the small seeds. There are typically one to three seeds per berry.
Before planting, scarify and soak seeds overnight. Then, press them on top of the soil. The seeds need light to germinate. Germination should take a few weeks. When true leaves have developed, you can transplant the seedlings into larger pots to continue growing.
Potting and Repotting
Plant asparagus ferns in pots or containers in loose, well-drained potting soil. Asparagus ferns grow quickly, and the tuberous roots can easily break a pot. Plan on repotting often. 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 new pots filled with fresh potting soil. Water well.
Overwintering
If your outdoor temps begin to dip below 55 degrees Fahrenheit, bring your potted asparagus ferns inside. Keep them in bright light, away from drafts and radiators. Make sure to keep soil moist, but do not let the root stand in water, as this can cause root rot.
Pests and Diseases
Common Pests & Plant Diseases
Spider mites, aphids, and mealybugs like to hang out in this plant’s leaves; get rid of them with insecticidal soap.
Overly wet conditions can cause root rot. Avoid overwatering to prevent these issues.
Common Problems
While relatively easy to grow, asparagus fern does have a couple of issues that are easily remedied if you know what you’re looking for:
Yellow Leaves
Asparagus fern’s leaves will turn yellow if the plant has pests—like spider mites or mealybugs—or if your plant isn’t getting enough sunlight.1 Remove the pests, place in brighter light, mist your plant, and this should resolve the problem.
This plant’s leaves may also turn yellow if it’s over-fertilized (the solution is to fertilize less often), or if it has too much or too little light.
If your asparagus fern is turning brown and looks like it’s drying out, it could be that you have under-watered it. Cut off the brown, dried sections, and try watering more often.
Dropping Leaves
One of the biggest nuisances with asparagus fern is dropping foliage, which can litter floors and tables with fine dried-out needles. This normally happens because of inconsistent watering. While these plants don’t like to soak in water, neither do they like to be parched. The right watering rhythm can be especially difficult in colder climates, where indoor air can be very dry during the winter. More frequent watering and misting is usually the solution to a plant that is badly shedding.
III. Uses and Benefits
- It can be grown in borders or along foundations in areas where it can withstand the winter.
- It creates an interesting cover for the ground. Put it in containers, hanging baskets, and other types of pots. Houseplants that are grown in containers thrive in bright, sun-filtered spaces within the home.
- Florists place a high value on green stems because of their usefulness in enhancing flower arrangements.
