Many folks seeking a little potted evergreen for the holidays buy Norfolk Island pine (Araucaria heterophylla). These Christmas tree look-alikes are very popular as houseplants, although they can also present as stately outdoor trees in appropriate hardiness zones.
If the foliage of your lovely Norfolk pine is turning brown or yellow, jump in and try to determine the cause. Although most browning Norfolk pine foliage results from problems with cultural care, it may also indicate diseases or pests. Read on for information on how to figure out the cause of yellow/brown Norfolk pine branches.
Yellow/Brown Norfolk Pine Troubleshooting
Whenever you spot yellow/brown Norfolk pine foliage, your first and best step is to walk through the cultural care you are giving your houseplant. These trees can live a long time in pots indoors or out, but they need very specific conditions to thrive.
Every tree has a hot/cold temperature range that it prefers; those forced into winter or summer conditions outside their tolerance won’t grow happily. If you notice your Norfolk pine with yellow leaves, the temperature is the first suspect.
These trees thrive outdoors in USDA plant hardiness zones 10 and 11. All Norfolk pines are sensitive to frost and branches yellow and die as temperatures dip below freezing.
Likewise, very high temperatures can also cause yellow/brown Norfolk pine foliage. If your tree was outdoors (potted or not) in these extreme temperatures, you have likely found why your Norfolk pine is turning brown.
Temperature is not the only potential cause of yellowing or browning Norfolk pine foliage. The amount and type of sunlight is also important.
Norfolk pines require ample sunlight, but they don’t like direct sun. Your Norfolk pine with yellow leaves might be suffering from either too much direct sun or too little rays. Move it to a spot where it gets plenty of indirect light. In the summers, try moving your houseplant Norfolk outside beneath a tall tree.
Irrigation is important to Norfolk pines, especially when the weather is warm. Winters you can back off irrigation a little, but when you see browning Norfolk pine foliage, you might want to start watering a little more generously. Humidity is also important.
Pests and Disease
Pests and diseases can also cause browning or yellowing Norfolk pine. A Norfolk pine with yellow leaves might have developed a fungal disease, like anthracnose. You’ll know your tree has this disease if you first see spots on the leaves, then entire branch sections yellow, brown, and die.
Often, the real problem when your Norfolk pine is turning brown from anthracnose is that you are keeping the foliage too wet. Stop all overhead irrigation and allow the foliage to dry out. You can also spray the tree with a fungicide.
On the other hand, if your Norfolk pine with yellow leaves has mites, you’ll need to raise the humidity. Mites are pests that hide in the foliage, but you can discover them by shaking the tree over a sheet of paper. If raising the humidity doesn’t get rid of the mites, use insecticidal soap spray.