The Japanese black pine is an evergreen pine tree and should always be placed outdoors. It is widely used for bonsai and much appreciated because the rough bark makes it look old early on. The Japanese black pine produces needles 3-4 inches long which are grouped by two.

Position

The Japanese black pine should be kept outside all year round. It tolerates light very well, so do not hesitate to place it in a south exposition to offer plenty of light all day long. The Japanese black pine is very resistant to cold winter, but like any other bonsai tree, because it grows in a small container, it will need to be somewhat protected during the coldest temperatures.

Watering

The Japanese black pine can bear some periods of under-watering but try to keep the soil slightly moist at all times.

Fertilizing

You should fertilize your Japanese black pine twice in spring and another time in fall. If your tree is vigorous, you can fertilize only once in spring and once in fall.

Repotting

Repot your Japanese black pine every 3 to 5 years, ideally in spring. Make sure you use an optimal soil mix as your Japanese black pine is very sensitive to the quality of the soil it grows into. Choose a soil max made of 70% of akadama and 30% of sand.

Pruning

Cut the candles between April and August when the tree is at full growth. Look for the gap on the candle (where there is almost no needle) and cut before this gap. Then clean the needles after the cut and save only 6 to 8 pairs of needles. In fall, you can cut branches that have grown too long and are modifying the structure you want for your bonsai tree.

Wiring

Wire your bonsai in fall or winter and leave the wires on until the following summer.

Propagation

The Japanese black pine is best obtained through grafting, or from seed. Air layering is also possible with this species.

Pests and diseases

The Japanese black pine can be attacked by mealybugs and aphids. Spray the branches with water if there are only a few pests on the tree, or apply an organic treatment if there are too many of them.

Did you know?

The Japanese black pine has a variety of shapes in nature, because it needs to accommodate to all the rude environments it grows in. This species originated from Japan and grows near the shores. Strong winds and storms force the tree into a specific shape, and also helped the tree to grow very resistant with time.