Defoliation is an advanced technique where by all of the leaves are trimmed off a bonsai tree in the summer. This process causes the tree to grow new, smaller leaves and increase the ramification. Defoliation is also said to stimulate twice the usual growth in the next period of growth.
What Is Defoliation And Why Is It Used?
Defoliation is the technique of removing all of the leaves from a bonsai tree, usually by hand. This technique accomplishes a few different things so can be used for a variety of purposes. The most common uses are to cause the tree to grow smaller leaves, which can help restore the balance or aesthetics of a tree. Defoliation can be done on specific areas of a tree to help aid the create of a specific aesthetic. This process is also said to stimulate double the usual growth in the next growing season.
Can My Tree Be Defoliated?
This process is very hard on trees, so do not try to defoliate a tree with any sort of health issues or weakness. This means that bonsai that have diseases, have been recently re potted or just been aggressively pruned should not be defoliated. Typically different species are effected differently by defoliation, however, it’s a rule of thumb to stay away from any evergreen species and only defoliate deciduous trees. As a precaution, it’s advised not to try and defoliate the whole tree as a beginner or if you have any doubts about the vigor of the tree – instead, start with a quarter of the foliage and see how the tree responds.
When To Defoliate?
As a general rule, defoliating a bonsai tree around June is the best time of year as this will hopefully give the leaves enough time to grow in before the winter comes. It’s worth noting that this is somewhat species dependent, some species such as the oak and elm will be best defoliated in May.
Partial vs Complete?
Partial defoliation has a lot of benefits compared to a full defoliation. Firstly, there is less chance of a beginner making a critical mistake that will result in the tree dying, which could very well happen with a complete defoliation. Different species and trees will react in different ways – it’s safer to partially defoliate and check in with how the tree is reacting to the process, rather than fully committing without seeing how the tree is responding.
The partial process can be used to easily shape the tree and restore the aesthetics of the bonsai. This can be easily achieved by only defoliating one area of the tree, for instance the top, meaning the leaves will be growing back smaller in size, giving the tree a more authentic look. Should just general growth be what you’re after, defoliating the larger leaves on the outside of the branches will allow more sunlight into the inner leaves, promoting more growth – this process can be continued throughout the growing period to increase size.
Complete defoliation can take place once the leaves are hardened off, meaning the leaves become a darker green color and much tougher. One huge benefit of removing all of the foliage is that more experienced bonsai enthusiasts can really go to town with shaping and wiring their tree from this point, as it’s objectively a lot easier to see the branches and shape of the tree. Checkout this full guide I wrote about wiring your bonsai tree – it contains everything you’ll need to know!
How To Defoliate A Bonsai (Step By Step Guide)
Check that your tree is suitable for defoliation. (Species, health and vigor of the tree, time of year)
Clean your leaf cutter or pruning scissors.
Find the area of tree that you are looking to defoliate (unless you’re doing a complete defoliation, in-which case, the whole tree).
Prune the leaves off, leaving the stems intact.
Here is a defoliation video, brought to you by BonsaiEmpire that could be very useful for beginners. In essence it’s a very simple process to actually perform, it’s just checking the health of the tree that is the most important part to ensure the tree can survive something so stressful.
There isn’t too much aftercare needed, which came as a surprise to me, thinking the tree would need a lot of care after something so shocking. Besides continuing the usual care procedures you have in place, if you have defoliated the outer foliage it’s important to keep the tree in a mostly shaded area for 3-4 weeks, in order to protect the inner leaves that have now been completely exposed.