Indoor Asparagus: Growing and Care

Botany and description

The indoor Asparagus belongs to the botanical family Asparagaceae, a group of herbaceous and climbing plants that also includes edible species like garden asparagus (Asparagus officinalis). Its genus name, Asparagus, comes from the ancient Greek “asparagos”, meaning young shoot, referring to the fine, ramified stems characteristic of these plants.

Asparagus illustrations (circa 1920)

In French, Asparagus is often called indoor asparagus, ornamental asparagus or even asparagus fern, although it is not a true fern. In its natural habitat, it is mainly found in South Africa and Asia, where it grows as climbing or bushy plants in bright, humid undergrowth. Its fine, airy foliage allows it to efficiently capture the light filtered through the canopy.

Its popularity as a houseplant stems primarily from its light and elegant foliage, reminiscent of the delicacy of ferns, as well as its robustness. It adapts well to indoor conditions, tolerates occasional watering lapses and thrives in medium light, making it an ideal choice for greenery enthusiasts, even beginners.

Among the most commonly cultivated species, Asparagus plumosus is undoubtedly the most prized for its finely divided, almost feathery foliage, which adds an ethereal touch to any interior. Meanwhile, Asparagus sprengeri, sometimes called “florist’s asparagus”, is more often used in hanging baskets for its trailing habit and rapid growth. Other species like Asparagus densiflorus and Asparagus setaceus are also popular, each offering a unique variation of this light and graceful foliage.

The very discreet flowering of Asparagus setaceus

Asparagus plumosus

When young, Asparagus plumosus adopts a gracefully upright silhouette, but over time it develops voluble, climbing stems capable of clinging to a support if provided. Its fine, flexible stems extend into an airy tangle, giving the plant an ethereal appearance.

At the base, a fleshy, fibrous root system develops in the form of tubercles, allowing it to store water and withstand short dry spells. Unlike trees or bushes, it lacks a true trunk; its stems emerge directly from the stump and branch abundantly.

The foliage of Asparagus plumosus is actually made up of cladodes, false needle-shaped leaves that unfurl in their thousands, forming a light, airy mass. This almost feathery appearance earned it its name. In spring or summer, it may produce tiny white or greenish flowers, very discreet but fragrant, sometimes followed by small spherical berries, green then black at ripeness.

Asparagus plumosus (© Forest and Kim Starr)

Asparagus sprengeri

Asparagus sprengeri, on the other hand, has a more arched, trailing habit. Rather than climbing, it forms soft clumps that cascade elegantly, making it perfect for hanging baskets or pot edges. Its stems are thicker and stiffer than those of plumosus, though they retain some flexibility.

Again, the fleshy roots allow the plant to survive irregular growing conditions.

Its foliage, though similar to plumosus, is slightly coarser, with more spaced-out cladodes and a brighter green hue. When flowering, it produces small whitish flowers, often followed by bright red berries, adding an extra ornamental touch.

Left, Asparagus sprengeri (©Forest and Kim Starr). Top right, Asparagus setaceus and bottom right Asparagus densiflorus Myersii

When and how to plant an indoor Asparagus in a pot?

Indoor Asparagus is best planted in spring, the ideal time to allow it to adapt to its new environment and benefit from active growth resumption. However, it can be planted at other times of the year, provided extreme cold or excessive heat is avoided.

The ideal substrate

An Asparagus thrives in a light, well-draining and slightly humus-bearing substrate. A mix consisting of houseplant compost, sand or perlite for drainage and a bit of compost or turf to maintain good water retention is perfect. The goal is to avoid overly compact soil, which could suffocate its tuberous roots.

Where to place it?

Asparagus prefers soft, indirect light, so it appreciates a bright spot without direct sunlight, which could scorch its delicate foliage. An east or west-facing position is ideal, though it tolerates partial shade. It can withstand heated interiors but prefers a temperature between 15 and 25°C, with moderate to high ambient humidity. In overly dry air, its cladodes yellow and drop more easily. To prevent this, regular misting with non-calcareous water or using a humidifier can be beneficial.

Which pot to choose?

Asparagus develops a strong, tuberous root system that can quickly fill its pot. It’s therefore important to choose a wide and deep pot, at least 20 to 25 cm in diameter for a young plant, and opt for a breathable material like terracotta, which promotes evaporation of excess moisture. A plastic pot also works but retains more water, requiring careful watering adjustments. Always ensure it has drainage holes to prevent waterlogging.

Steps for potting an Asparagus

1. Prepare the pot: place a layer of clay pebbles or gravel at the bottom to improve drainage.
2. Fill with substrate: mix your compost with sand or perlite, then pour some into the pot.
3. Position the plant: gently remove the Asparagus from its original pot. If the roots are too dense, tease them apart lightly with your fingers.
4. Place and firm: position the plant in the centre and add substrate around it to cover the roots. Press lightly to stabilise without compacting too much.
5. Water moderately: water generously right after planting, then let the compost surface dry slightly before the next watering.

Repotting Asparagus

As Asparagus is a fast-growing plant, it requires repotting every 1 to 2 years, usually in spring. The need for repotting is evident when roots emerge from drainage holes or growth slows despite good growing conditions. When repotting, proceed as for planting by choosing a slightly larger pot (2-3 cm more in diameter) and renewing some of the substrate to provide fresh nutrients.

Please note: if the plant becomes too large, this is also an opportunity to divide the stump by carefully cutting sections of tuberous roots, each bearing a few stems, to create multiple plants.

Cultivation and Care of Asparagus

Indoor Asparagus is a robust and easy-going plant, but some regular care will help it maintain its beautiful airy foliage and vitality.

Watering: finding the right balance

Asparagus prefers a slightly moist but never waterlogged growing medium. Its tuberous root system allows it to store water, making it tolerant to occasional missed waterings.

• In spring and summer, during active growth, water approximately once or twice a week, allowing the surface of the compost to dry out between waterings.
• In autumn and winter, reduce the frequency to once every 10 to 15 days, as the plant enters dormancy and uses less water.

The watering water should be lime-free and at room temperature, ideally rainwater or filtered water. Avoid standing water in the saucer at all costs, as it promotes root rot.

Fertilisation: giving growth a boost

A nutrient supply helps the Asparagus maintain dense, lush green foliage.

• From March to September, add a liquid fertiliser for green plants every 2 to 3 weeks.
• In winter, fertilisation can be stopped or reduced to once a month if the plant continues to grow slightly.

If your asparagus turns yellow despite proper watering, a lack of nutrients may be the cause. In this case, more regular fertilisation or repotting with fresh compost can restore its vigour.

Pruning: is it necessary?

Asparagus does not require strict pruning, but some light maintenance will keep it looking neat.

• Cut dry or yellowed stems at the base to encourage new shoot growth.
• To control its development or restore a more compact shape, you can cut back some stems in spring. The plant tolerates pruning well and will regrow quickly.
• For climbing varieties like Asparagus plumosus, you can train the stems onto a support or shorten them if they become too invasive.

Precautions and points to watch

• Beware of overly dry air: Asparagus does not tolerate very dry environments well, especially in winter with heating. Regular misting or a humidifier will help it maintain full foliage.
• Avoid direct sunlight: too much exposure can cause burns on the cladodes.
• Watch out for cold draughts: it dislikes temperatures below 10°C.
• Handle with care: some varieties, like Asparagus sprengeri, have tiny thorns on their stems that can irritate the skin.

→ Read also: Indoor Asparagus: how to care for it season by season?

Asparagus setaceus

Potential Pests and Diseases of Indoor Asparagus Fern

Asparagus is a robust and relatively hardy plant, but it can still fall victim to a few parasitic and fungal issues, especially indoors where dry air and poor air circulation encourage certain problems.

The most common parasites

• Spider mites: these tiny mites appear mainly when the air is too dry. They cause yellowing of the foliage and fine webbing under the stems. To prevent them, it’s essential to increase ambient humidity by misting the foliage with water or placing a container of water nearby. If infested, wiping the leaves with a damp cloth and spraying with soapy water can be effective.

• Mealybugs: they form small cottony clusters at the base of stems or under the cladodes. These parasites suck the sap and weaken the plant. To remove them, use a cotton bud dipped in 70° alcohol or apply a natural treatment with diluted black soap.

• Aphids: less common, they sometimes settle on new shoots. They can be removed with a strong jet of water or a mixture of water and black soap.

• Thrips: these tiny insects leave silvery spots on the leaves and weaken the plant. A simple daily spray of non-calcareous water can help get rid of them.

Possible diseases

• Root rot: this is the most common issue, usually caused by overwatering or poor substrate drainage. The tuberous roots rot and the plant quickly declines. To prevent this, water moderately and ensure the pot has drainage holes. If the roots are affected, repot the Asparagus in dry substrate after cutting away the rotten parts.

• Leaf spots and yellowing: brown or yellow spots may appear if the plant is exposed to direct sunlight, if the air is too dry, or if it lacks nutrients. Balanced fertilisation and proper humidity management help limit this issue.

• Mould and fungi: excess moisture and poor air circulation can encourage mould growth on the substrate or stems. If this occurs, reduce watering and ventilate the room to improve the plant’s environment.

Prevention and best practices

• Ventilate the room regularly to prevent humidity-related diseases.
• Inspect the foliage and stem bases occasionally to spot parasites early.
• Avoid overwatering and use well-draining substrate to prevent root rot.
• Wipe the foliage with a damp cloth occasionally to remove dust and limit parasite attacks.

How to propagate Asparagus?

Asparagus can be propagated in two main ways: by dividing the tuberous roots and by sowing. Division is the simplest and quickest method, while sowing requires more patience.

Dividing the clumps (the easiest and quickest method)

Division is the ideal technique for propagating an Asparagus while rejuvenating a plant that has become too dense in its pot. It is best done in spring, when repotting, as the plant resumes its growth.

Steps to follow:

1. Remove the plant from the pot: gently take the Asparagus out of its pot by tapping the sides to free the roots without damaging them.
2. Separate the clumps: using your hands or a sharp knife, divide the root ball into several sections. Each section should contain tuberous roots and several healthy stems.
3. Repot each section: place each division in a new pot with a fresh, light, and well-draining substrate.
4. Water lightly: moderate watering will help the plant settle in without risking root rot.

The new plants will quickly resume their growth and develop beautiful foliage within a few weeks.

Sowing (a slow and delicate method)

Propagation by sowing is possible if the Asparagus has produced red or black berries, which contain seeds. This method takes more time, as the seeds take several weeks to germinate and the plant will need several months, or even years, to reach a good size.

How to sow Asparagus?

1. Harvest the seeds: once the berries are ripe (red or black), collect the seeds by cleaning them thoroughly under water.
2. Soak the seeds: let them soak for 24 hours in lukewarm water to soften their coating and encourage germination.
3. Prepare the substrate: use a mix of light and sandy compost to ensure good drainage.
4. Sow on the surface: place the seeds on top of the compost and cover them with a thin layer of substrate.
5. Maintain moisture and warmth: water lightly and place the pot in a warm (20-25°C) and bright spot, out of direct sunlight. Covering the pot with plastic film or a mini greenhouse helps retain moisture.
6. Patience! Germination can take 3 to 6 weeks, sometimes longer. Once the seedlings are well developed, they can be transplanted individually.

Indoor Asparagus: Where and How to Showcase It?

With its airy and delicate foliage, Asparagus adapts to many interior styles, adding an elegant and light natural touch. It is particularly suited to boho, Scandinavian, tropical and vintage settings, but can also blend into more modern décors thanks to its graphic appeal.

Where to place it for a beautiful display?

• Elevated or hanging: trailing varieties like Asparagus sprengeri look stunning in hanging baskets or on wall shelves, where their foliage can cascade freely.
• On furniture or a bright windowsill: Asparagus plumosus, with its gracefully arching stems, will find its place on a console, dresser or bookshelf, adding greenery without overwhelming the space.
• In an open terrarium: its fine, lightweight appearance makes it an excellent candidate for open terrariums, where it can coexist with other tropical plants like fittonias and mosses.

Asparagus setaceus, Asparagus sprengeri and Asparagus plumosus kokedama (© Gergerly Hideg)

Which pot to choose to enhance it?

• A raw terracotta pot: perfect for boho, rustic or Mediterranean styles. It also promotes good drainage.
• A ceramic pot in neutral tones (white, beige, light grey): ideal for Scandinavian or minimalist interiors, highlighting the delicate texture of its foliage.
• A wicker or rattan planter: perfect for a natural and cosy atmosphere.
• A macramé hanging pot: enhances the airy quality of Asparagus, especially trailing varieties.
• A glass terrarium: for a more contemporary or urban jungle look, Asparagus plumosus can be grown in a large open terrarium, where its fine foliage will create a fairy-tale effect.