Backyard Gardening

By Kathryn Dorman

I don’t put up a regular Christmas tree anymore.  I blame our cats.  In the past, one of our cats liked to climb the Christmas tree, and two of them liked to chew on the light bulbs.  Our three current cats have their own “cat tree” that they can climb, but I still don’t trust them to leave a full-sized Christmas tree alone.  I compensate by putting up all kinds of little trees.  Young Norfolk Island pines (Araucaria heterophylla) are often lightly decorated at Christmas time.  They present a bright, cheerful, living alternative for holiday greenery, and are available in many stores at this time of the year (See Photo).

Norfolk Island (N.I.) pine is not truly a pine.  It doesn’t belong to the Pinaceae family.  It is, however, a conifer, or cone-bearing tree, in the Araucariaceae family.  There are about 19 Araucaria species, which are all native to the southern hemisphere.  According to Penn State University Extension (PSU), the genus name is derived from the Araucanian Indians of Chile.  There are several tree species related to N.I. pine, including the Chilean monkey puzzle tree (Araucaria araucana). 

Norfolk Island pines are native to Norfolk Island, which is located in the South Pacific, east of Australia.  N.I. pines were first documented in 1774 by British explorer, naval officer, and cartographer Captain James Cook.  The specific name for N.I. pine, heterophylla, is a Greek word which means “different leaves.”  Young leaves are needle-like, and curve down.  Mature leaves overlap and are more scaly in appearance.  

In their native habitat, N.I. pines will grow on cliffs overlooking the ocean and within temperate rainforests.  They can reach heights exceeding 200 feet (https://extension.psu.edu/norfolk-island-pines).  In the United States, Norfolk Island pines can be grown outdoors only in humid areas of Zones 10 and 11 (Florida, parts of California).  In other states, including Pennsylvania, N.I. pines should be grown only as houseplants.  Their preferred temperature range coincides with typical home thermostat settings, between 65 and 75 degrees Fahrenheit.

The Norfolk Island pine should receive just a couple of hours of daily sunlight.  According to North Carolina University Extension Gardener Plant Toolbox (NCSU), afternoon shade may prevent the bleaching or yellowing of foliage (https://plants.ces.ncsu.edu/plants/araucaria-heterophylla/).  The plant will grow toward sunlight.  In order to maintain its graceful, symmetrical shape, rotate the plant a quarter turn about once a week.    

Only water the Norfolk Island pine when the soil feels dry to the touch.  It will need higher humidity than is typical for a Pennsylvania home in winter.  This can come from running a humidifier nearby, misting with a spray bottle, and/or placing the plant on a tray filled with water and clean pebbles.  Do NOT allow the plant to sit in standing water!  Every three or four years, or when roots become visible above the surface of the soil, the plants should be repotted (PSU).  Use fertile, slightly acidic, well-drained potting soil (NCSU).

The Norfolk Island pine can be decorated for the holidays.  Since the branches are soft, only use lightweight ornaments.  If you decorate with lights, it would be better to use a string of LEDs, which will not give off heat.  Heat may damage the plant’s needles.

Norfolk Island pines may be purchased as seedlings and young trees.  Size options depend on your price range, and are limited to the height of ceilings in your home.  They can be kept alive for many years, but keep in mind that they will continue to grow in height!  

Years ago, I had a Norfolk Island pine tree.  I knew it needed lots of humidity, so I kept it in the bathroom.  I should have realized that it needed at least a couple hours of sunlight every day.  Unfortunately, I killed it.  Incidentally, this was decades before I became a Master Gardener!  I’ve been thinking about getting another Norfolk Island pine tree.  I already bought one for my niece for Christmas this year.  I figured I should do some research, because I know that she will want to keep this plant alive.  I plan on keeping my new Norfolk Island pine tree alive this time, too!  

Kathryn Dorman has been a Penn State Extension certified Master Gardener of Clinton County since 2017.  She can be reached at clintonmg@psu.edu, or through the Clinton County Master Gardener Hotline at (570) 858-0198.