Japanese White Pine Bonsai Care Guide

The Japanese white pine is a very hardy species that can tolerate harsh conditions well and should be kept outdoors. Look for a spot that receives bright and full sun, the white pine will not thrive indoors. Pines are tolerant of shade but will grow longer needles to compensate for less light, a feature which is considered undesirable in bonsai art.

Action does not necessarily need to be taken during the winter as these species require a cooler period of about three months for dormancy. However, be aware that if the pot and soil freeze over, the pine will die of dehydration. We therefore recommend protecting your tree from frost and freezing temperatures. Consider using a cold frame or bringing it indoors to an unheated space such as a greenhouse to more safely allow for its dormancy period.

There is no definitive guide to watering and it should be conducted on an observational schedule, not a routine. This means that it is important to keep an eye on the moisture levels of the soil to avoid over and under watering, both which can lead to dropping leaves and/or root death. The amount of water a bonsai requires depends on pot size, climate, airflow, soil and tree type so it is best to use your eyes and fingers to assess whether the soil is damp, wet or dry. 

If the top inch or so of soil has dried, it is ready to be watered. When you water, try to get an even coverage over the roots and soil, allowing water to flow out from the bottom of the pot to ensure a good soaking.

If you are a first-time bonsai owner, another way to water is by submerging the entire pot in water until the bubbles stop. If you choose this method, be aware that your bonsai may not need watering for another two to four days, but this will depend on the factors mentioned above such as soil type, pot size and climate.   

Japanese white pines dislike permanent moisture so a well-draining soil is required and be careful not to overwater. Protect the trees from excess rain while shoots are developing because a lot of water will make the needles grow longer than necessary.

Using fertiliser on your Japanese white pine will help encourage healthy growth and this should be done periodically from once a week to every two months and only during the growing season. You can start adding Chrysal Liquid Bonsai Feed to your water from March until October and use weekly. Use Naruko Fertiliser Slow Release Bonsai Feed once every one to two months. With Buddhist Pine trees, less is more, and we tend to advise using half the recommended dosage to see how your Buddhist Pine reacts first.

Pruning your bonsai is important not only to maintain or create an aesthetic style but to also ensure light and airflow can reach inner foliage. Japanese white pines grow quickly upwards, at the expense of lower branches and inner shoots. You can pinch back the growing tips during summer to thin out its growth and encourage lower branching and a more balanced structure. When new buds appear (candles), let them grow to around 3cm in length, and then cut them back down with sharp scissors to about halfway. If there are more than two candles on one branch or twig, remove the surplus but be sure to leave two. Do not remove all the candles at one time as this can result in death of the pine.

Training your Japanese white pine is possible as the branches are supple and can be bent easily, even into older age. Wire them from early autumn to early spring and leave the wires on for a long while, the white pine grows very slowly and is likely to bend back to its original shape if taken off too early. We recommend using wires with a thickness that matches the thickness of the branch: if the wire you choose is too thick you will damage the bark. If it is too thin, it won’t be effective.

Repotting your tree is an important way to provide a fresh and suitable soil mix and ensure appropriate root health. Repot in early spring, just after the buds begin to swell and extend. Generally, your white pine will need to be re-potted once every two years if it is young, while older ones can stay in their pots for longer. However, you should always check if it has become root-bound before you change pots. You can do this by lifting the tree gently out of the pot by the main trunk and examining the root system. You will know it is ready if you can see that the roots are circling around each other and the pot. If, however, they still appear contained in the soil, you should place it back and wait until the following spring to check again.

Trees that are ready for repotting will require root pruning, a suitable new pot and appropriate soil mix.

When repotting, do not cut back the root mass by a large amount, and choose a well-draining soil mix that has a neutral or slightly higher PH value of 5-6 but not over 7. We tend to use a mixture of different speciality bonsai soils on our trees. Every species is different so please contact us for free soil-mix advice or to take advantage of our repotting service.