Asparagus fern care guide

The asparagus fern is not a true fern. It is a cousin of the asparagus you eat. It grows soft, feathery sprays of tiny green needles on thin, wiry stems. Under the soil, it has fat, white tuber roots that store water. That makes it more forgiving than a real fern. It is toxic to cats and dogs.

Light

Give it bright indirect light. An east window is ideal. A few hours of morning sun is fine.

Hot afternoon sun turns the needles yellow and crispy. In low light, it grows thin and sparse.

Water

Water when the top 2 to 3 cm (1 in) of soil is dry. Water until it drains, then empty the saucer. In winter, it needs water less often.

The tuber roots hold water, so it can handle a missed watering. If the soil stays dry too long, it drops a shower of tiny yellow needles. Read how to tell if a houseplant is overwatered or underwatered.

Soil and potting

Use a well-draining houseplant mix.

The tuber roots grow fast and fill the pot. They can push the soil up or crack a thin pot. Repot every year or two in spring, one size up. See how to repot a houseplant step by step.

Humidity and temperature

Average room air is fine. Keep it away from heat vents. Hot, dry air makes it drop needles.

It likes cool rooms. Keep it between 13 and 24°C (55 and 75°F), and above 10°C (50°F).

Feeding

Feed monthly in spring and summer with a balanced liquid fertilizer at half strength. Skip feeding in fall and winter.

Pruning

Cut old, yellow, or bare stems off at the soil. New stems come up from the roots.

Wear gloves. The stems have small, hooked thorns.

Propagation

Divide it in spring. Ease the plant out of its pot. Cut the root mass into two or three pieces with a clean knife. Each piece needs stems and some tubers. Pot each piece up and water it.

It can also grow from the seeds inside its berries. Seed is slow and the berries are toxic, so division is the easier choice.

Problems

What you see	Most likely cause
Tiny yellow needles dropping	Dry soil, dry air, or too much sun
Brown, crispy sprays	Too much hot sun, or soil left dry too long
Long, bare stems	Age, or not enough light. Cut them back.
Soil pushed up, pot cracked	Crowded tuber roots. Repot or divide.
Fine webbing between needles	Spider mites
Yellow stems and soggy soil	Too much water

Pests

Spider mites are the most common pest, most of all in dry winter air. Mealybugs and scale can hide in the dense growth. Rinse the plant in the shower to knock pests off.

Pet safety

The ASPCA lists asparagus fern as toxic to cats and dogs. Eating the red berries can cause vomiting, stomach pain, and diarrhea. Repeated contact with the sap can cause a skin rash. Keep it out of reach, and pick off berries as they form.

Varieties

• Lace fern, Asparagus setaceus, has flat, lacy sprays. It is the classic asparagus fern.
• Asparagus setaceus ‘Nanus’ is a compact form that stays small.
• Sprengeri fern, Asparagus densiflorus ‘Sprengeri’, has longer, arching stems with flat needles. It suits a hanging pot.
• Foxtail fern, Asparagus densiflorus ‘Myersii’, grows stiff, upright plumes like fluffy tails.