Asparagus fern

Asparagus fern: how do you recognise it?

Habit

First a compact, spreading plant of 30–50 cm; later long climbing or trailing stems of 80 cm or more.

Foliage

The ‘needles’ are fine, flattened stems arranged in flat, fern-like tiers. The true leaves are tiny scales.

Stems

Thin and wiry, with small, sharp spines.

Flower and berry

Older plants sometimes produce tiny white flowers, followed by berries that ripen from green to purplish black.

Roots

Fleshy, tuberous roots that store water; they fill the pot quickly and sometimes push the plant upwards.

Plants: March–April · Pruning: March–April

Why grow it?

• Fine, airy foliage that adds a lacy touch among large-leaved house plants.
• Copes with less light than many house plants, as long as it gets no direct sun.
• Evergreen and attractive all year, with no bare resting period.
• The sprays last well in a bouquet and have long been used by florists.
• Older plants can be trained up a small trellis or left to trail from a hanging pot.

Asparagus fern: where does it grow best?

• Bright light to light shade, without midday sun: an east or west window, or a spot set back from a south window.
• Room temperature of 15–22 °C; never below 10 °C.
• Prefers some humidity: in a dry, heated room the needles drop more quickly.
• Keep it away from radiators and draughts.
• In summer it can go outside in a sheltered, shady spot from late May to September.

Light

Bright, out of direct sun

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

0.8 m tall, 0.6 m wide

Temperature

Minimum 10 °C

Goes well with

• Snake plant: Stiff, upright leaves as a contrast to the fine foliage.
• Spider plant: Just as easy, and lovely in a hanging pot next to the asparagus fern.
• Boston fern: Also likes light shade and humid air.
• Ivy: Also climbs or trails, with firmer leaves.
• Flowering begonia: Colourful flowers against a cloud of fine green.

Asparagus fern: when and how to plant it?

Plant in March–April.

1. Repot in March or April, when the roots fill the pot or appear above the compost.
2. Choose a pot one size larger, with a drainage hole and a layer of clay pebbles at the bottom.
3. Use good house plant compost, if you like lightened with a little garden compost or sand.
4. Set the plant at the same depth as before; the fleshy roots may sit just below the surface.
5. Firm lightly and water until it runs out of the bottom; empty the saucer.
6. Wear gloves: the stems have small spines.

Care

Water

From spring to autumn keep the compost lightly moist; let the top centimetre dry out between waterings. Never leave water standing in the saucer.

Humidity

Stand the pot on a tray of wet clay pebbles or group it with other plants. Occasional misting helps in winter.

Feeding

From April to September, liquid house plant feed at half strength every two weeks.

Repotting

Every one or two years in spring, or divide it when the pot is overcrowded.

Support

Train the climbing stems of older plants along a small trellis or wire.

Tip: When the fleshy roots push up out of the compost, it needs a bigger pot. Don’t be afraid to cut back a bare plant: it usually regrows fresh.

Asparagus fern: when to prune it?

Pruning months: March–April.

When: In March–April, when repotting. Dead stems can be removed at any time of year.

How:

• Cut bare, yellow or dried-out stems right back to the base; new shoots will come from the rootstock.
• If the whole plant has gone bare, cut all stems back to just above the compost: it usually regrows fresh.
• Shorten overlong climbing stems to keep the plant compact.

Caution: Wear gloves: the stems have fine spines.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April, cut the root ball into two or three pieces with a sharp knife and pot each piece separately.

Seed

Ripe berries provide seed. Sow fresh seed in spring in moist seed compost at 20–25 °C; germination takes several weeks.

Asparagus fern: how does it get through the winter?

• Indoors all year: it cannot take frost and needs at least 10 °C.
• In winter preferably a little cooler (12–15 °C) and bright, with less water: let the compost dry out more, but never completely.
• No feeding from October to March.
• Dry air from central heating is its worst enemy: raise the humidity.

Diseases and pests

• Needle drop: Yellow or brown needles that fall point to dry compost, dry air or too much sun. Give it bright light out of direct sun, water more regularly and cut out bare stems.
• Red spider mite: Fine webbing and mottled, greyish foliage in dry air. Rinse the plant in the shower and raise the humidity.
• Mealybug and scale: White fluffy tufts or brown bumps on the stems. Wipe them off with a cotton bud dipped in methylated spirit, or rinse the plant.
• Root rot: A limp, yellowing plant in wet compost. Water less, repot in fresh compost and cut away rotten roots.

Through the year

• January: Little water. Check for red spider mite and mealybug.
• February: Raise the humidity. Get ready for repotting.
• March: Repot or divide. Cut bare stems back to the base.
• April: Start feeding every two weeks again. Water as soon as the surface is dry.
• May: From late May it can go outside in the shade.
• June: Water and feed regularly. Check for red spider mite.
• July: Water. Train or shorten climbing stems.
• August: Water and feed. Keep it out of strong sun.
• September: Bring it back indoors before cold nights. Last feed.
• October: Water less. Stop feeding.
• November: Place it somewhere cool and bright, away from the radiator.
• December: Little water. Raise the humidity.

Edible and useful

Not edible. Asparagus fern is related to the vegetable asparagus, but do not eat any of it: the berries, which turn from green to purplish black, are poisonous and cause vomiting, stomach ache and diarrhoea, in children as well as in cats and dogs. The sap can irritate the skin, especially if you handle the plant often, and the stems have small, sharp thorns: wear gloves when pruning and repotting. Keep the pot out of reach of small children and pets, pick up fallen berries, and do not put a bouquet with asparagus fern where your cat chews greenery either. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Did you know?

• Despite its common name it is not a fern: it produces flowers and seeds, and belongs to the same family as the asparagus you eat.
• The fine ‘needles’ are not leaves but tiny flattened stems that do the work of leaves.
• In warm regions such as Australia it has escaped from gardens and is controlled as an invasive weed.