Foxtail fern (Asparagus densiflorus) care

Other · easy to keep

Last updated 26 October 2026

Foxtail fern (Asparagus densiflorus) wants bright indirect light. Water it weekly. Keep the compost lightly damp in spring and summer, letting the top few centimetres dry between waterings. The tubers store water, so it forgives a missed watering far better than a real fern — but not a pot left standing wet. Pot it in moisture-retentive peat-free compost with perlite. A weak balanced feed monthly in spring and summer, and repot once a year. Humidity: room humidity is fine; more keeps the foliage fuller. Toxic to cats and dogs.

Foxtail fern and Sprenger's asparagus are two forms of this one tough, tuberous-rooted plant: Sprenger's arches and trails, while the foxtail form grows dense upright plumes. Not a fern at all, and much more drought-tolerant than one. The stems carry small hooked spines, so wear gloves to handle it.

Quick facts

Water: Water weekly. Keep the compost lightly damp in spring and summer, letting the top few centimetres dry between waterings. The tubers store water, so it forgives a missed watering far better than a real fern — but not a pot left standing wet.
Light: Bright indirect light.
Humidity: Room humidity is fine; more keeps the foliage fuller.
Soil: Moisture-retentive peat-free compost with perlite.
Feeding: A weak balanced feed monthly in spring and summer.
Repotting: Repot once a year.
Toxic to pets: Toxic to cats and dogs. The berries cause vomiting and the sap can give a skin rash — and despite the name it is not a fern at all, but a relative of asparagus. The ASPCA lists Asparagus Fern (Asparagus densiflorus cv sprengeri) as toxic to cats and dogs (checked 26 October 2026).
Difficulty: Easy.
Mature size: 40–60 cm tall and wide.
Native to: South Africa.

Watering a Foxtail fern

Water weekly. Keep the compost lightly damp in spring and summer, letting the top few centimetres dry between waterings. The tubers store water, so it forgives a missed watering far better than a real fern — but not a pot left standing wet.

That cadence is the one PlantParlour sets for this species when you name it, and it is deliberately on the cautious side — a plant that asks a day early is safer than one that asks a day late. Log each watering and the reminder moves with the plant rather than with the calendar.

Light

Medium indirect light, and never direct sun. A bright north window or a well-lit bathroom is close to ideal.

Humidity and temperature

Room humidity is fine; more keeps the foliage fuller. Central heating in winter is what turns a comfortable room into a dry one, and it is the usual reason an established plant suddenly browns at the edges or picks up spider mites.

Soil and potting

A mix that holds water without turning to mud: compost with perlite and a little bark. Ferns have fine roots that must never dry out completely.

Feeding

A weak balanced feed monthly in spring and summer. Stop feeding in autumn and start again when you see new growth in spring — feeding a plant that isn't growing just builds up salts in the pot.

Repotting

Repot once a year. Every spring. Divide the clump at the same time if it has filled the pot.

Common problems

Yellowing, shedding needles
Too dark, or the pot dried right out.

Fix: Move it brighter and water more regularly. Cut bare stems back to the base; new ones come up from the tubers.

Yellow leaves: how to read it on any plant
Yellowing stems in a pot that stays wet
Overwatering — the tubers rot if they sit wet.

Fix: Let the top third dry out between waterings, and make sure the pot drains.

Yellow leaves: how to read it on any plant
Fine webbing and pale speckling
Spider mites, which like its dense foliage in dry air.

Fix: Shower it thoroughly and treat every week for a month.

Spider mites: how to read it on any plant

Propagation

Divide the tuberous root ball in spring. It is tough work; a serrated knife helps.

A cutting taken in PlantParlour keeps its link to the plant it came from, so a propagation years later still traces back to the mother plant — which is the point if you ever sell or trade it.

Toxicity and safety

Toxic to cats and dogs. The berries cause vomiting and the sap can give a skin rash — and despite the name it is not a fern at all, but a relative of asparagus.

The ASPCA lists Asparagus Fern (Asparagus densiflorus cv sprengeri) as toxic to cats and dogs (checked 26 October 2026).

If your pet has eaten a plant, call your vet, the ASPCA Animal Poison Control Center on (888) 426-4435, or the Pet Poison Helpline on (855) 764-7661. Both are open around the clock and may charge a consultation fee. Take the plant or its label with you.

This is general information, not veterinary advice. We don't test plants: what we say about toxicity follows the ASPCA's published plant list as it stood on 26 October 2026, and that list can change. "Non-toxic" means not poisonous — a pet that eats enough of any plant can still vomit, and fertiliser, pesticide or leaf shine on a plant can harm it. It also only helps if the plant is what you think it is. It covers cats and dogs only; ask your vet about rabbits, birds, reptiles or anything else, and a doctor about children. Read our terms.

Every houseplant in the library the ASPCA lists as non-toxic to cats and dogs

Questions people ask

How often should you water a Foxtail fern?

Water weekly as a starting point — that is the cadence PlantParlour sets for Asparagus densiflorus. Keep the compost lightly damp in spring and summer, letting the top few centimetres dry between waterings. The tubers store water, so it forgives a missed watering far better than a real fern — but not a pot left standing wet. Light, pot size and the time of year all move that number, so treat it as a reminder to go and check rather than a rule.

How much light does a Foxtail fern need?

Medium indirect light, and never direct sun. A bright north window or a well-lit bathroom is close to ideal.

Is Foxtail fern toxic to cats and dogs?

Toxic to cats and dogs. The berries cause vomiting and the sap can give a skin rash — and despite the name it is not a fern at all, but a relative of asparagus. The ASPCA lists Asparagus Fern (Asparagus densiflorus cv sprengeri) as toxic to cats and dogs (checked 26 October 2026). If a pet has eaten part of a plant, call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 straight away.

How do you propagate a Foxtail fern?