Norfolk Island pine is a needled evergreen native to subtropical regions in the South Pacific. Despite the name, it is not an actual pine tree, but rather a relative of the monkey puzzle tree. In its native environment (Norfolk Island, near New Zealand) this tree can grow to be 200 feet tall, and it is often cultivated as a landscape tree in subtropical climates in North America (USDA zones 10 to 11). It has a very straight trunk and pleasingly symmetrical branches covered with short, inward-curving needles.
In other regions, the slow-growing Norfolk Island pine is often grown as a living Christmas tree, frequently decorated with ribbons or ornaments. All too often, the tree is discarded after the holiday season, but it can easily be kept as a permanent foliage plant if kept below 5 feet or so in height.
|Botanical Name||Araucaria heterophylla|
|Common Name||Norfolk pine, Norfolk Island pine|
|Plant Type||Needled evergreen|
|Mature Size||Up to 200 feet tall in the wild; 3 to 8 feet tall indoors|
|Sun Exposure||Full sun; can tolerate shade|
|Soil Type||Sandy, peaty soil; peat-based potting mix|
|Soil pH||4.5 to 5.5 (acidic)|
|Hardiness Zones||10 to 11, USDA (grown as a houseplant elsewhere)|
|Native Area||Norfolk Island in the Pacific|
How to Grow Norfolk Island Pine
Norfolk Island Pines are capable of growing both indoors and out. While they have preferred growing conditions, they are quite forgiving and can thrive in a variety of settings. Outdoors, plant this tree in porous, moderately moist, porous/sandy soil in a full sun location. Once established, it will tolerate somewhat dry conditions.
When grown as an indoor plant, use a potting mix that is porous, sandy, and slightly acidic. Adding extra peat moss and sand to a standard potting mix will improve its acidity and porosity. Keep the soil damp, but not soggy, and give the plant as much light as possible.
Although they are full-sun plants whenever possible, Norfolk Island pines can also handle relatively long periods (months at a time) in dimmer conditions. Thus, you can keep your potted plant inside during the winter, and then move it to a sunny spot outside when the summer comes around. If your plant begins to stretch while growing inside, the odds are that the combination of low light and heavy fertilizer is causing leggy growth. In that case, cut back on the fertilizer until the plant has more access to sunlight. It's helpful to turn it frequently so every side gets equal light.
These are acid-loving plants. For indoor plants, a peat-based potting mixture is perfect for them as the mix will gradually acidify as the peat breaks down.
When planted outdoors in the garden, this tree prefers a sandy but rich soil, preferably amended with peat.
Norfolk Island pines are somewhat drought-tolerant, so they forgiving where water is concerned. It's advisable to let the soil dry out slightly between waterings. Keep an eye on the needles: if they turn yellow, your plant needs more water.
Temperature and Humidity
As they are from the South Pacific, Norfolk Island pines prefer warmer, wetter climates between 65 and 70 degrees Fahrenheit. They can survive cooler and warmer temperatures briefly but may perish if they experience temperatures below 35 degrees Fahrenheit. To help your indoor plant maintain humidity, mist it regularly with a spray bottle or place it over a saucer of water (don't allow its roots to sit in the water, though). However, this plant is more forgiving of dry indoor air than most subtropical plants.
Feed your Norfolk pine with a weak liquid fertilizer throughout the growing season, although it is best suspend fertilizing in low-light periods.
Norfolk Island pines—especially younger trees—have notoriously weak root systems, which is how they earned the name "suicide tree." To strengthen their roots, make sure you're supplying regular fertilizer and don't hesitate to stake your tree up if it needs it.
Potting and Repotting
A potted Norfolk Island pine will do pest in peaty, sanding potting mix that is slightly acidic. Young Norfolk Island pines are not very fast growers, so it might be possible to repot your tree every other year instead of every year. As the plant matures, it will begin to grow faster. Repot your Norfolk Island pine in the springtime, and if your plant has attained a larger size, make sure to use a pot with plenty of heavy material in the mix, such as potting sand, to provide enough weight to keep the plant upright.
Pruning Norfolk Island Pine
Lower branches that die back should be removed—a common issue with indoor specimens. It is usually not recommended to trim the top of the tree, but if a potted tree gets too large for its space, the central leader can be cut off. This will cause the tree to branch out from that point, and while you will lose the classic evergreen look, such trimming usually does not affect the health of the tree.
Trees grown outdoors should have any dead and diseased branches removed, but other than this, no routine pruning is necessary.
Propagating Norfolk Island Pine
The Norfolk Island pine is a gymnosperm, meaning that a single plant contains male and female reproductive organs. Virtually all Norfolk Island pines are grown from seeds that are usually imported from the Pacific region. Most home growers will never bother with seeds or propagation.
Varieties of Norfolk Island Pine
There is only one variety on the market: Araucaria heterophylla. This plant does not have cultivars or named varieties. A few other species from this family sometimes show up in the trade, mislabeled as the original plant. These include A. columnaris, A. araucana, and A. bidwillii. It's unlikely you'll see these, but if you happen to acquire one, the cultural requirements are similar.
Toxicity of Norfolk Island Pine
Norfolk pine is mildly toxic to cats and dogs. If pets ingest the needles, they may experience stomach and mouth irritation along with vomiting. Norfolk pine is not known to be toxic to human beings.