Spring is an exciting season for bonsai growers. New buds begin swelling, growth accelerates and our trees start showing signs of renewed activity. It is also an important repotting period for many bonsai species, but that doesn’t mean every tree needs a new pot this spring.
One of the best indicators is the condition of the root system. If roots have become densely packed around the inside of the container, drainage has deteriorated or water struggles to penetrate the growing medium, repotting may be necessary.
Soil condition matters too. Bonsai substrates gradually break down and become compacted, potentially reducing drainage and the amount of oxygen reaching the roots. A tree that has remained in the same substrate for several years may therefore benefit from attention.
However, don’t repot simply because September has arrived. Species, age, health, climate and how long the tree has been in its current container should all influence the decision. A weak or recently stressed bonsai may benefit more from being left undisturbed.
For South African growers, spring provides an excellent opportunity to inspect your collection carefully. Check the roots, observe drainage and research the needs of the particular species before reaching for those root cutters.
Sometimes the best bonsai work is knowing when not to interfere.