Pruning is without a doubt the most important part of making a bonsai actually look like a miniature tree, rather than a shrub in a tiny pot. This process requires removing up to 20% of the foliage, usually around the top of the tree to create the desired look and increase the ramification of the tree. In this article I’ve aimed to teach you everything you need a know about pruning a bonsai, along with a step by step guide!
Trees are used to always competing for light so they will naturally grow larger and fuller leaves at the top. Although this is extremely useful for them in there natural environment, it’s less needed in the art of bonsai. Pruning (essentially removing foliage), is needed to remove a lot of these larger leaves, allowing the foliage beneath it to get light and thrive. More so, without pruning the bonsai will get incredibly overgrown and look like a standard nursery stock shrub, not a work of art.
There are two main types of pruning, the most common being routine pruning. This is where you are going to be removing a lot of foliage, usually from the top of the tree, or dead foliage from nearer to inside. Routinely pruning is something you’ll be doing all year round and every few weeks in the growing season – you’ll grow to love it! The other type is structurally pruning, where you will be removing larger branches from the tree. Although this is technically more dangerous for the health of the tree, done properly it will cause no long lasting damage and help bring the bonsai to its desired shape.
The Best Time Of Year To Prune A Bonsai
The safest time of the year to prune your a bonsai tree depends on which type of pruning you’re looking to undertake. A normal routine pruning (nothing do to with large branches) can be done all year round but preferably in the growing season during the Summer. If you are more interested in pruning larger branches and making structural changes to your bonsai, this changes from species to species so there is no ‘one size fits all’ answer to give. Typically this shouldn’t be undertaken during the summer, unlike maintenance pruning, but I would advise doing some research into the actual species requirements.
It’s important to touch on the fact that deciduous trees can be pruned using a good pair of pruning shears whereas species with needles such as the White Pine should have the needles removed by hand. If you use the shears to prune the needles, you are going to leave bits of needle still in the branches will will soon turn brown and die. Pinching them away by hand allows you to leave nothing there to eventually turn brown.
Pruning Your Bonsai (Step By Step)
What You’ll Need:
Step 1 – Locate the area you want to prune. (Don’t just go in pruning random areas)
Step 2 – For thin branches, cut these shoots off using the pruning shears.
Step 3 – For just a standard maintenance prune, try to remove more that 25% of the trees foliage.
Step 4 – If you’re also wanting to remove larger branches, use the concave cutters.
Step 5 – Remove half of the branch you want to get rid of first. This will allow you to make a clean second cut.
Step 6 – Now that’s out of the way, cut the rest of the branch off, getting a clean, tight cut against the adjoining section of the tree.
Step 7 – Apply the wound paste in a small amount to any of the larger branch cuts made.
Maintenance Pruning Aftercare
If you have removed around 20% of the foliage and nothing structural (larger branches), this isn’t going to put much stress on the tree and the risk of infection is very small. Keep your tree watered and getting a lot of sunlight – it will be absolutely fine and you’ll see new buds growing in the summer within a few weeks.
Should you have undertaken the pruning of larger branches, you’ll need to put a small amount of wound paste on the cuts. This is the brand of paste I bought on Amazon.
This process is going to help the trees wounds recover a lot faster and limit the possibility of the wounds getting infected, which could be a disaster for the bonsai. Beyond that, the standard maintenance of watering and sunlight is going to be all your tree really requires.
What Happens If You Don’t Prune A Bonsai?
Some bonsai owners will choose not to prune the tree for years for a number of reasons. Firstly, nothing bad is going to happen if you don’t prune a bonsai, it’s a growing tree and it’s just going to keep growing. One of the hardest aspects of bonsai is to keep the miniature tree actually looking in proportion to a full sized tree, which is mainly due to an effect called apical dominance. This means that bonsai trees will typically grow larger leaves at the top, making it look very unlike the tree you’d find outdoors. This natural process is counteracted by routinely pruning the tree.
Another reason people may choose to not prune a bonsai for a long time is because they’re looking to increase the size of the tree, mainly the trunk. By planting the tree or just routinely repotting it and letting it grow out with no pruning or structural adjustments, the tree will dramatically increase in size over the coming years. Achieving a thick trunk with such a small pot is a really hard feat to achieve, something I’m still working on with my trees, so not pruning for years can be a useful technique. You can learn more about this in my guide detailing how to thicken the trunk of a bonsai tree.
In conclusion, if you don’t prune a bonsai tree it’s going to be absolutely fine but just not look too much like a bonsai tree anymore as it will lack the ramification and pruning that all great bonsai trees have.
Defoliation Of A Bonsai
Defoliation is similar to pruning in some respects but it’s a much more advanced process and doesn’t fall under the routine care list. The purpose of defoliation is to force the tree to grow smaller leaves in the area you have defoliated – to increase ramification. Bonsai trees typically like to grow larger leaves at the top of the tree, which leads to an aesthetic that doesn’t really mirror that of a full sized tree – that’s where defoliation comes in. This is due to apical dominating which essentially forces trees to grow taller to avoid the risk of being shaded by other trees. Although this is a natural process, in terms of bonsai it will lead to the lower foliage dying out and the tree being top heavy.
Whereas whilst pruning you are removing relatively few leaves, whilst defoliating you are either removing all of the leaves on the tree, or all of the leaves in a certain area. It’s a very simple process that can be undertaken during the summer months, typically May or June. The new leaves that grow back will have less growing season, meaning they will be smaller. If you are interested in learning more, I have a full defoliation guide here.
Unlike pruning, it’s best to only defoliate deciduous species, completely avoiding the evergreens. If you’re looking to do a full defoliation, you have to ensure that the tree is extremely healthy and doesn’t have any sort of weakness whereas with pruning it’s not going to be stressful enough to any tree to be a concern. I wouldn’t advise doing this process unless you feel like you need to as it does put a lot of stress on the bonsai. For most situations beginners would find themselves in, a standard pruning routine is going to be adequate.