How To Care For Your Japanese Black Pine Bonsai Tree

Pinus Thunbergii Bonsai Care

About The Japanese Black pine Bonsai Tree

The Japanese black pine tree is a stiff needled pine tree that is all around dark.  Dark bark, and dark green needles, make this one of the most sought after trees for bonsai.

Placement

Like most pine trees, a Japanese black pine bonsai should remain outdoors all year long.

It must stay cool or cold during the winter (about 3 months), but should be protected from harsh freezes.  In the late fall, protect your tree by burying your tree, or mulch over the pot in the ground. The tree should be protected from strong wind and sun (but not snow or rain) throughout the winter.  If you must, it can be placed in an unheated garage or shed.

Do not forget to water your tree in the winter!

In the early spring, when the chance of freezing is gone, it can be placed back in its normal location.

For the rest of the year, the tree should be outside with a few hours of sun (morning sun, with afternoon shade is best.)

Watering

Never let the soil completely dry out.  Whenever the soil seems dry, thoroughly water your tree until the water runs clear from the bottom.  In the growing season, this can be daily.

If you need help, a good moisture meter will guide you.

Humidity

If you ever need to take your Japanese black pine bonsai tree inside, including into a garage for the winter, using a humidity tray is recommended.  It will prevent the water from running on the floor, and can help keep the tree somewhat moist in the dry season.

Fertilizing

Since your Japanese black pine bonsai is in a small pot, and not the ground, it needs nutrients.  A slow release (pellet based) fertilizer is perfect for this, and can be added sparingly every 1-2 months during the growing season.

Pruning & Trimming

Trim back the new growth to the farthest safe point that looks good to you — but never remove all of the new growth.

A regular trim will help keep your Japanese black pine bonsai tree short, while helping the trunk grow thicker.

Repotting

Repotting must be performed periodically on your bonsai, Japanese black pine included, when its root system has filled the pot.  If you can clearly see the roots coming out of the bottom of the pot, it’s time to repot your bonsai.

Generally, this means every 2-3 years for a deciduous tree and every 4-5 years for an evergreen.

Repotting should be done in mid-summer, when the tree is at it’s least fragile state.

The pine bonsai tree, along with all of its soil, should be removed from the pot.  From there, you can trim away no more than 1/3rd of the root mass (1/4th is preferred.) 

Then you can repot the tree in the same pot, or give it a newer / bigger pot to thrive in.

After repotting, your Japanese black pine bonsai should be thoroughly watered.

Diseases, Insects & Other Pests

Your Japanese black pine bonsai can be treated for pests like a normal Japanese black pine tree.  Just remember, your tree is miniature and will need a much smaller and more gentile dose of treatment.