How to Grow and Care for Asparagus Fern

Several species of the Asparagus genus are commonly known as asparagus fern—especially A. densiflorus, which is typically grown outside, and A. aethiopicus, which is typically grown as a houseplant. While different species, both are very similar plants with bright green feathery-textured foliage.

Neither plant is a fern, but instead, they are warm-weather perennials closely related to the common edible garden asparagus. In zones 9 to 11, these plants are hardy outdoors, where they grow as creeping spreading plants, but it is also common for them to be grown as indoor houseplants, where they make good "thriller" specimens in mixed containers or hanging baskets.

Normally planted in the spring, the fast-growing 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—to the point of serious invasiveness. Check with your local extension agent to determine if it's invasive in your area.

Indoors, the key to a robust asparagus fern is to keep the plant properly watered, bushy, and dense, so its lace-like foliage forms an attractive mound.

Asparagus fern is mildly toxic to humans and moderately toxic to pets.

Asparagus Fern Care

If you live in hardiness zones 9 or warmer, you can grow asparagus fern outdoors as a perennial. Outdoors, these plants will prefer a partial shade location in organically rich, moist, well-draining soil. In all other climates, it can be planted as an annual or kept indoors as a houseplant. It's also popular as an outdoor container plant, where it is often used as a thriller in mixed plantings. You can bring the container inside when the weather turns cold.

Asparagus fern's “leaves” are leaf-like cladodes. The true leaves are barely visible scales near the base of the cladodes. While the ferns look soft to the touch, they're quite sharp. Wear gardening gloves if you plan to prune an older plant. When asparagus fern is content in its location, it can produce small flowers followed by berries that are mildly toxic. The berries are toxic to cats and dogs.

Light

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.

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.

Water

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.

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.

Fertilizer

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.

Types of Asparagus Fern

There are several popular cultivars of asparagus fern, including:

• 'Myeri' has dense foliage on upright stems; it's known also as foxtail fern
• 'Sprengeri' boasts long stems and a full, almost fluffy, mounding form; it's also referred to as an asparagus emerald fern
• 'Sprengeri Compacta' has the same features as its namesake but is a dwarf variety
• 'Nana' features bright green foliage and is another compact variety

Pruning

Asparagus fern is a fast grower, and you may want to trim yours to keep it tidy. It's also okay if you leave it looking wild and shaggy. Use clean garden shears or sharp scissors to remove brown portions or to regenerate an older plant. Cut at the base, not in the middle of a stem.

Propagating Asparagus Fern

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:

1. 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.
2. 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.
3. 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 Asparagus Fern 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 Asparagus Fern

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.

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 With Asparagus Fern

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. 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.