Norfolk Island pine houseplant (Araucaria heterophylla): Home

This tropical evergreen tree is well loved for its vivid green needles and graceful, symmetrical form. It is not a true pine plant (family Pinaceae) but a member of the ancient plant family Araucariaceae, and native to humid, coastal areas of the tiny Australian territory Norfolk Island in the South Pacific.

The Norfolk Island pine is a tropical plant so it can only grow outdoors in the very warmest parts of the United States (USDA zones 10 - 11) where winter temperatures do not fall below the low 40's. In the New York City area, it can be grown indoors as a houseplant and the best conditions mimic its humid, tropical, native environment. The need for relatively cool conditions and  humidity in winter can be a challenge.  Norfolk Island pine houseplants are juvenile forms with a broad, conic shape. While unlikely to grow more than 6 inches in a year indoors, this plant will gradually become up to 20' tall with good care.

Light:

Araucaria should have bright, indirect light and will lose its dense growth form and eventually decline if kept too far from a window. Close to an east-facing window, a few feet back in a bright south-facing room, or with a western exposure but protected from direct, late afternoon light, will all allow it to retain its best foliage color and attractive shape.  Needles will fall off if the light is not strong enough. To keep its growth most symmetrical, turn it slightly every week.

Temperature:

The Norfolk Island pine grows best in temperatures between 60º and 70º F during the day and 50º to 65º F at night. Reduce the temperature to the lower end of this range in winter so that the plant experiences a rest, around 55 to 60º F. Protect the plant from exposure to drying air from a heat or air conditioning vent in its proximity. This plant is not a good, long-term choice for a home that is kept on the warm side.

Watering and Humidity:

When soil feels slightly dry to the touch, water your Norfolk Island pine thoroughly with tepid water, being sure that the water drains into a saucer. After 15 minutes, discard all excess water from the run off dish. Water should be slightly reduced along with temperature in winter so that the plant rests while light levels are low. The plant will use less water in these conditions but you should continue to keep the soil just moist and prevent it from drying out.

A relative humidity above 50% is preferred to successfully grow Norfolk Island pine indoors. Provide additional humidity by misting twice daily. An excellent, alternative method of providing extra moisture is to stand plants on shallow trays filled with moistened pebbles, and/or use a humidifier. Those techniques will work more effectively in the very dry air of a New York area home in winter. You can use a simple hygrometer to assess the humidity and keep it in the 50%+ range that Norfolk Island pines prefer.

Fertilizing:

Feed only during the growing season (March through September) with a dilute houseplant fertilizer, once every two weeks.

Potting and dividing:

Repotting Norfolk Island pine is best done in springtime. Usually, repotting is needed only every two to three years, but plants can be repotted when roots appear on the surface of the mixture or through the bottom of the container. Also note that the roots are rather delicate so handle the plant carefully.  Use a mildly acidic, soil-based potting mixture, with additions of peat moss and coarse sand/or perlite. A container with a drain hole is essential to keep this plant in good health.

Removing young North Island pines growing around a mother tree is also best accomplished in spring. If the mother plant is ready to re-pot, that can take place at the same time so that removing youngsters can be performed more easily and carefully. 

Moisten the soil a few hours before you remove your tree from the pot so that all the potted family comes out easily. Have fresh potting soil mixture on hand. Gently place the unpotted mother plant on its side and brush away the soil to expose the roots, at the same time carefully remove each young plant with roots gently, one at a time. Clean the mother's pot with soap/water mixture before reuse. Use a sterile pruning tool and small trowel if needed to separate from the mother's roots.  Pot up each plantlet in their own clean container (5 inch).  Water in with tepid water.

Propagation:

Tip cuttings and dividing emerging plantlets are the easiest way to propagate in a home environment. Only a tip cutting from the very top of Norfolk Island pine (Araucaria heterophylla) plants will develop into a completely symmetrical specimen. Once you take that cutting, your Norfolk pine will no longer grow from the top and will lose its attractive symmetrical shape. Horizontal growth cuttings do not develop into an erect tree.

New plantlets may grow from the soil at the base of your plant and can be potted up individually to create new trees as described above in Potting and dividing.

Propagation by seed is considered difficult and, even in well-controlled settings, successful outcomes may be limited. One significant constraint is that seeds vary considerably in quality, and fresher, carefully selected and stored seeds have the best outcomes. Older, more dried seeds do not produce good results.   Plants produced by seed may have greater internode spacing, considered less desirable as houseplants than trees grown from tip cuttings.

A greenhouse setting is the most successful when propagating by seed. There are two resources in the side bar of this guide, from the University of Florida and Reforestation, Nurseries, & Genetic Resources, with detailed instructions for seed propagation if you would like to explore further. 

What to watch for:

These plants drop their branches when they are under stress because their cultural requirements - particularly adequate water and light - are not met. Unfortunately, the branches will not grow back. Check that your plant has the following for improvements.

• It needs to be in an east, west or south-facing window. Northern light is not strong enough. Western light will be okay if you can protect it from harsh late afternoon sun by keeping it slightly further from the window. The position in the room should allow bright, indirect light.
• It must be in a container with a drain hole and fast draining soil. This simulates its native habitat where the rain runs through the soil quickly. Always empty out the run-off dish 15 minutes after watering.
• Humidity in the room should be above 50%. Again, this is like its native habitat and helps to keep the branches healthy and regulate evaporation from the soil. You can keep the pot and run-off dish on a wet pebble tray if necessary or use a humidifier. A simple hygrometer kept near the plant will tell you if the humidity is in the right zone.
• Check that the plant is not near an air conditioning or heating vent. The strong blasts of air that has a hotter or colder temperature create a real stress on this plant that grows in a temperate rainforest. Check for vents on the floor or ceiling that might go unnoticed.
• Norfolk Island pine needs relatively little fertilizer and one or two applications per month in spring and summer is enough. Too many feedings will make the plant structure weak.
• Water when the soil feels dry and be consistent. Do not let the roots dry completely and don't keep the soil wet.

Browning needles can occur for a variety of reasons. It’s normal for the older needles on the lower branches to gradually turn brown and drop off. But if large areas or areas other than the lower branches turn brown, then there is probably something else going on. These plants like humid environments and cool temperatures, but here are some additional reasons why this might be happening:

• In most homes the humidity is too low for the plant. During a cold winter, heaters come on more frequently and really dry things out. This is very frequently the source of this problem.
• Overwatering or underwatering can cause brown needles. Overwatering can occur if the plant container does not have a drain hole or if the run off dish isn't emptied after watering. Underwatering is especially likely if the pot is too small; a pot full of roots use up the water quickly.
• Norfolk pines like lots of bright, indirect light. They can take a couple hours of direct sun, as long as it's not harsh midday sun. Too much direct sun can burn the needles.
• Blasts of cold air or hot air can brown the needles. Keep the tree away from doors and windows where cold gusts might come in, and away from heating vents and radiators.
• These plants can be prone to spider mites, which love warm, dry conditions. Inspect the brown areas for any webbing produced by the spider mites. You can use water to rinse them off and try to knock down the populations. More even watering and increased humidity will also help with mites.

Lanky or asymmetrical trees result when light levels are too low. Give the Norfolk Island pine more natural light, especially in the winter months, to assure dense, symmetrical development.

A plant that fails to grow upward and adds only lateral growth may have a damaged or missing terminal growth tip.