Advice - Repotting

Acers prefer slightly acidic soil that is well-drained and aerated.

Repot every 3 to 5 years, before buds emerge in February or March. You can use the same pot or a larger one, but always replace at least half the substrate.
A 50-50 mixture fine pieces of pine bark (available in garden centres and agricultural cooperatives) and compost provides good results; don’t hesitate to add a drainage layer at the bottom of the planter (use gravel or pot shards).We strongly advise against using the heath earth available in stores, as it is often made using peat with modified pH. It is quite water-repellent in summer, and retains too much water in winter, which causes the root system to rot.

Repotting should be done in the spring, every year or every other year depending on whether the tree is young or old, before the buds come out in late February or early March, depending on your region.
For Acers imported from Japan, we recommend using a mixture of three parts good quality hard akadama soil that has dried for at least two years, and one part kanuma soil.
Be sure to thoroughly untangle the roots and arrange them around the trunk to form the nebari in a star shape. Clean the roots carefully, train them, and prune them. Don’t forget to anchor the tree firmly in its pot.