Monstera

Identification and origin

Monstera deliciosa, a member of the Araceae family, is native to southern and eastern Mexico and to Guatemala. Although it is often sold as a “philodendron,” it does not belong to that genus. The epithet deliciosa refers to its edible fruit.

In the wild, the plant germinates on the ground, then climbs into trees to about 69 ft, clinging with long aerial roots. Juvenile leaves are small and solid. Mature leaves are dark green, glossy and leathery; they develop oval holes on either side of the midrib and split in from the margin. These openings are thought to let wind pass through without tearing the blade. In a pot, leaves commonly reach 12 in and the plant 6–8 ft.

Indoor plants rarely flower. The fruit takes 12 to 14 months to ripen after flowering; its green, hexagonal scales fall away from the base toward the tip, revealing pulp that tastes of banana and pineapple. Only the pulp that comes away easily is edible: the still-green part contains highly irritating crystals.

Variegated cultivars include ‘Albo Variegata’, rare and expensive, and ‘Thai Constellation’, speckled with creamy white, whose shorter internodes make a fuller plant.

Light

Bright but filtered light, near an east- or west-facing window. Prolonged direct sun easily scorches the large leaves, so let the plant adjust gradually to any change in exposure. In winter, some direct sun is beneficial.

In too much shade, it produces stretched stems and small leaves without splits. Variegated cultivars need more light.

Watering

Water thoroughly, then empty the saucer after about fifteen minutes. Wait until the top quarter to third of the mix has dried before watering again.

There is no universal schedule: needs change with the season, light, warmth, pot and mix. Check the mix with a finger. From fall to late winter, keep the root ball just barely moist, since root rot is more common in cool weather.

What to watch for: droplets at the leaf tips point to a mix that is too wet; brown edges often mean the air is too dry. If the plant climbs a moss pole, moisten the moss as well so the aerial roots can anchor into it.

It likes air humidity above 50%. A humidifier or a tray of moist pebbles helps in dry air. Wipe dust off the leaves regularly.

Potting mix

A mix rich in organic matter, slightly acidic to neutral and, above all, well drained: an indoor potting mix lightened with bark, perlite or charcoal works well. Always use a pot with drainage holes. From spring to late summer, feed with a balanced fertilizer at half strength every two to four weeks; reduce or stop in winter.

Temperature

Comfortable temperatures: 61–84 °F. In winter, a cooler period between 55–64 °F gives the plant a beneficial rest; growth resumes only above about 64 °F. Avoid dropping below 55 °F and keep it out of cold air currents.

It cannot tolerate frost: leaves are damaged around 30–32 °F and stems around 27–28 °F. Hardy in USDA zones 10a to 12b, it can live outdoors year-round only where winter lows stay above about 30 °F. Elsewhere, it can spend the summer outside in a sheltered spot as long as nights stay above 45 °F.

Repotting

Monstera tolerates being pot-bound far better than being over-potted, since a large pot keeps the mix wet. Repot in spring, only when roots have filled the pot or come out of the holes, into a container just slightly larger. Beyond that, simply replace the top layer of mix every other year.

Choose a heavy pot: the plant becomes top-heavy and tips over easily. Install a sturdy support, such as a moss pole on which to tie stems and aerial roots; without it, the laden stems break or sprawl.

Pruning

Prune in spring if the plant outgrows its space, just above a node, with clean tools and gloves, since the sap can irritate the skin. The shoots that follow first bear smaller leaves with fewer splits.

Do not remove aerial roots without reason: they help the plant cling and feed. Lower ones can be guided into the mix, upper ones attached to the support or cut if they are in the way. The gradual loss of the oldest leaves is normal.

Propagation

Stem cuttings: take a section with at least one node and, ideally, an aerial root. Stand it in water in bright light until it has a good set of roots, then pot it up. A stem that already has aerial roots can also be planted directly, buried to within 2–3 in of the first node. Spring and summer are the best seasons.

Air layering: 12–18 in from the tip of a stem, make an upward-slanting cut about a third of the way into the stem and hold it open with a toothpick. Wrap it in moist sphagnum moss and cover with clear plastic. Roots appear within a few weeks; once they are well developed, cut below the wrap and pot it up.

Common problems

• Mealybugs: white, waxy clusters, sticky honeydew and sooty mold.
• Spider mites: fine webbing and tiny pale dots on the leaves.
• Scale, aphids, thrips: brown bumps on stems, or insects on young shoots.
• Bacterial leaf spot: dark brown spots with a yellow halo; avoid cold and crowding, improve airflow.
• Anthracnose: leaf edges that yellow and then turn brown; avoid wetting the foliage.
• Root rot: a plant that wilts even though the mix is moist, with brown, mushy roots; too much water or poor drainage.
• Many yellow leaves: overwatering, lack of fertilizer or cold.
• Dry brown edges: air too dry, mix left dry too long or direct sun.
• Leaves without splits: a young plant, too little light or no cool winter rest.

The same symptom can have several causes: look at all the conditions (light, watering, temperature, humidity, roots) before making changes.

Toxicity

The whole plant, except the fully ripe fruit, contains insoluble calcium oxalate crystals. It is toxic to dogs and cats: burning of the mouth, tongue and lips, excessive drooling, vomiting and difficulty swallowing. In people, eating it burns the mouth and throat, and the sap can irritate the skin. Only the pulp of fully ripe fruit is eaten, and some people are allergic to it.

Keep it out of reach of children and pets. If any part is swallowed, contact a veterinarian or a poison control center.