Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
What are Norfolk Island Pines?
As their name implies, Norfolk Island pines (Araucaria heterophylla) are indigenous to the Norfolk Islands in the South Pacific as well as Australia, New Zealand and New Caledonia. They are not true pine trees. Norfolk Island pines are members of an ancient plant family called Araucaria whose members are found in the South Pacific and southern South America. Their leaves resemble needles and their seeds develop in cones so they are often mistaken for pines.
In their natural environment, Norfolk Island pines are very tall growing to a height of 200 feet. They are also very long-lived, often reaching an age of 200 years old. Their cones take 18 months to mature. Here in the US, they are only hardy in zones 9 through 11. They prefer full sun, but will grow in low light so they can be grown indoors as houseplants.
Norfolk Island Pines Make Great Christmas Trees
Most people become acquainted with Norfolk Island pines during the Christmas season. They are sold in supermarkets, plant nurseries, florist shops and home improvement stores as living Christmas trees. They can be decorated with ornaments, lights, garlands or stars. In small homes and apartments that don’t have room for a full sized Christmas tree, a Norfolk Island pine is the perfect size for a Christmas tree. And after the holidays, it makes a wonderful houseplant.
How to Grow a Norfolk Island Pine as a Houseplant
Even though it prefers full sun in its native environment, Norfolk Island Pines can survive in the low light found in our homes. They just grow more slowly. The slow growth also means that you will only need to repot them every 2 or 3 years instead of annually. You will know that it is time to re-pot when you see roots growing out of the bottom of the pot. When repotting, getting the soil mix right is important. You need to mimic the soil found in its native environment which is island shores with rocky, well-drained soil. You can use soil meant for succulents or you can mix your own. Mix equal parts of sterile potting soil, peat moss and either sand or perlite for drainage.
These trees like to be dry so only water when the top inch of soil is dry. Then water thoroughly, until water runs out of the bottom of the pot and into the saucer beneath. Empty the saucer. Do not allow the trees to sit in water. Despite their preference for dry soil, because they are from the seashore, they need 50% humidity. Most likely, your home is too dry so you will need to provide humidity either by using a humidity tray or by simply misting your tree several times a week. You can easily make a humidity tray. Simply take a tray with raised sides and fill it with sterile gravel. Then fill the tray with water and set your plant on top of the gravel but not in the water. As the water evaporates, it will create humidity for your tree. Be sure to refill the humidity tray when the water has completely evaporated to keep up the humidity.
During the winter, the trees rest. There is no need to fertilize them from fall until spring. In the spring, they begin growing again. You will see bright green new growth in the tips of the branches. This is the signal that you need to start fertilizing. Use a timed release 6-4-6 fertilizer. Gently scratch it into the soil every six weeks until the fall when the tree will stop growing and begin its rest period again.
Norfolk Island pines prefer cool temperatures indoors. They like daytime temperatures between 68⁰F and 72⁰F. At night, they are happiest when the temperature is between 50⁰F and 55⁰F.
You should also be aware that when you grow your tree indoors, it is getting its light from your windows which means that the light is only coming from one direction so the tree will naturally lean towards its single light source. To prevent your tree from permanently tilting, give it a quarter turn each week so that all sides of the tree will get sunlight each month.
How to Grow a Norfolk Island Pine From a Cutting
Most people buy Norfolk Island Pines as plants but you can grow your own. If you have access to a tree, you can grow another one via cutting. Take a 6 to 8 inch cutting from the growing tip at the top of the tree. The reason why you want to take your cutting from the top of the tree rather than from one of the side branches is that once a Norfolk Island Pine loses a branch, it does not grow back. So if you take a cutting from a side branch, it will not grow back and the tree will be lopsided.
Strip all the leaves from the lower half of your cutting and dip it into rooting hormone. Place your cutting in a pot filled with the same succulent or homemade soil mix that you use for mature trees that has been premoistened. Mist your cutting thoroughly and cover it with a plastic bag that is fastened by a rubber band on the pot. This is to create a humid environment for your cutting. Open the bag and mist your cutting every day. Water it as you do a mature tree, when the top inch of soil has become dry.
It will take 8 to 10 weeks for your cutting to develop roots. You can tell that it has grown new roots by gently tugging on the cutting. If there is resistance, it is the new roots that are resisting you. If the cutting comes right out of the soil, there are no roots yet. Once your cutting has developed roots, you can treat it as you would a mature tree.
How to Grow a Norfolk Island Pine from Seed
Commercial growers grow their trees from seeds collected from trees that grow on plantations in places like Hawaii. If you are fortunate enough to obtain seeds, you can grow your own trees from them. Surface sow the seeds 1 inch apart in pots filled with the same soil mix used for mature trees. Don’t cover them. They need sunlight to germinate. Mist them liberally and cover the pots with plastic wrap to hold the humidity in. If needed, use a heat mat to keep the soil at a temperature of 75⁰F and 85⁰F. Keep the soil surface wet by misting regularly. Germination should occur in 2 to 4 weeks. As the seedlings grow, remove the smaller seedlings leaving only the largest and strongest seedling in each pot. Once they have developed their first leaves, you can treat them like mature trees, watering only the soil is dry on the top inch of soil.
Questions & Answers
Question: Hi! I have a small Norfolk pine that I saved from two Christmases ago. It is growing very slowly but needs to be repotted. How large and or deep should the new pot be? Help!!
Answer: When repotting a large plant like a Norfolk Island pine, a good rule of thumb is to use a pot that is at least 2 inches larger than the pot your plant is in. So if your tree is in a 12-inch pot, you would want to transplant into a 14 or 16-inch pot.
Question: How tall will my Norfolk Island pine get?
Answer: It is up to you how tall your Norfolk Island pine will get indoors. They can grow up to 20 feet tall indoors, but most people prune them to keep them under 3 feet tall.
© 2018 Caren White