This is the largest section of the learning area as it combines a lot of bonsai techniques. This section can be skipped for now. You can always come back when you're eager to learn more.
At some stage you're going to need to remove foliage from your bonsai. Why do we do we do this though? Well, it is a matter of tree health and aesthetics. If your bonsai is not maintained, it will grow into a dense bush. That dense bushy growth will stop light from reaching foliage at the centre of the tree, which may then cause die back of foliage. Pinching, trimming and pruning ensures balanced and beautiful growth.
Each type of tree needs to be approached in its own unique way when it comes to pinching, trimming and pruning. Below I will cover the techniques that you will use for the most common types of bonsai, although I encourage you to research your particular species further. I highly recommend the website bonsai4me.com. If I was to give advice on each species of tree, I fear this blog may never see an end!
Before I get into detail on pinching, trimming and pruning, lets define some important terms. Pinching is the removal of soft new growth from a bonsai (normally with your finger tips). Trimming is the removal of excess growth with scissors. You may see me using the wording 'thinning' in the same sentence as trimming, just know that they're similar for now. Pruning is the removal of branches (normally thicker than a pencil) with a concave cutter or secateurs. With those three definitions mentioned, lets get into it!
Pinching is done in spring when the new growth of your bonsai extends. Most of the new growth on your bonsai will come from the tips of the branches. If we let the tree grow without intervention year after year, there would be no growth closer to the trunk. We want to keep our branches and foliage relatively close to the trunk to achieve an aesthetically pleasing appearance. One way to achieve this is to 'pinch' the new growth at its tip during the growing season. Pinching new growth shortens internodes (the space between nodes on a broadleaf tree) and also disperses the trees energy amongst the branches where you pinch. This growth is often soft and can be removed by your finger. If the tip begins to harden then you will need to use scissors to remove the stem, but then this becomes trimming.
Below are some examples of pinching on a few different types of bonsai. Remember that pinching is only done on new growth. To pinch, grab the tip of the shoot with your thumb and index finger and pinch in a pulling/twisting motion. The shoot should pluck away with ease. Avoid pinching the weaker areas of a tree as they need to grow more without interference. Pinch these later.
Remember, the reason we bud pinch is to keep a nice bonsai shape and to promote more growth on a certain part of the tree. If your bonsai appears to have dense foliage already, then less pinching is required. It should also be noted that pinching is a technique used on finished bonsai. Finished bonsai have a main trunk and secondary branches established already.
Pinching a Juniper
The important thing to know when pinching junipers is to only pinch the new tender growth that is 'extending'. Pinching new soft growth will keep the silhouette maintained and will encourage growth further back on the branch. Some minor tip browning is expected when pinching Junipers, but that will be overtaken by new growth over the coming weeks. Combine pinching with the trimming/thinning mentioned further on in this guide. Pinching does not thin out any growth, remember! If it's soft enough, pinch it. If it's too tough, cut it with scissors. Remember, pinching is more a pulling/twisting motion. Use minimal nail pressure. Don't pinch too many tips in one session.
Pinching Candles on Pine Bonsai
Pine bonsai are considered the most difficult to develop for beginners. We will cover it briefly, though, for the sake of including all types of pinching.
In summer and autumn, pines grow buds which will eventually grow into candles. As the name suggests, candles look like long white candles. In spring, these candles begin to elongate and fresh pine needles are revealed. If we allow the needles to open completely, then the candle will become a branch.
Put simply, if you don't want a branch to grow further on a pine, simply remove two-thirds of the candle (remove as the needles begin to open). Pinching will also encourage more buds to form at the base which means you can turn a single stem into an impressive branch with many stems (in time).
Candles will be stronger on some parts of the tree and weaker in other areas. Below are the different grades of candle growth on a pine. It is important that the weakest growth be left alone, and stronger growth managed (pinched or trimmed) to maintain balance on your pine tree. Never remove all of the candles at once. Lastly, don't wait to long to pinch. New candles can be pinched with your finger, older candles will need scissors. Once that candle has opened completely and the stem turns brown, you've lost your window, and pruning the branch will mostly like cause dieback.
Below you can see where a candle was cut last year. This created more buds around it, which grew to candles, which will then be branches. This is how a single stem can be divided into many. This is called ramification.
Pinching a Broadleaf Bonsai
Pinching can also be used on broad leaf species of tree such as the maple and Chinese elm. When you pinch a broadleaf bonsai, it will encourage one stem to split into two or more stems. This is good way to build density in your bonsai tree. When pinching out a bud, you want to wait for the leaves to unfurl a little, and then remove the new leaves and bud. In the picture below you can see new growth, I was a little bit too late here, but I can still remove the new growth. After pinching, growth will be stimulated further back, internode length will be reduced, and your bonsai will be kept in good shape. Remember that the strongest growth comes from the top of the tree. Aim to pinch top growth more than other areas of the tree to ensure balance. Also remember that pinching is only carried out on developed bonsai that have their main structure (trunk) and secondary branches established already. I recommend looking into 'bonsai ramification' if you want to know more about 'developed and refined' bonsai.
Trimming is done once spring growth has hardened, this is slightly different for each tree species but from mid spring to early summer is the approximate time. Trimming can be thought of as 'thinning' or the removal any plant material that isn't thicker than a pencil (anything larger than that is considered pruning). Trimming is done to keep unwanted growth in check and to encourage light, air, and space inside the tree. To do this, we remove undesirable branches from our tree. Further down the page there is a visual guide to what is considered undesirable. One of most undesirable types of growth are stems that grow out from the main silhouette of the tree. Below we will cover how to trim this back. Trimming is done throughout the growing season. Remember to trim the vigorous areas of the tree more than the weaker areas to establish balance. The apex (top of the tree) will be the most vigorous in most trees. As for the cut itself, when making a cut, use sharp scissors and cut on a 45-degree angle. Aim to cut right above a leaf node on broad leaf species, and cut further back on a stem for junipers. Never cut the juniper's needles directly, otherwise die-back will occur on the needles.
Trimming a Juniper
The juniper below can be trimmed to create space amongst the branches. Ensure you're cutting on woody growth and not the green needles. It is a great idea to trim before you wire so there is less growth in your way.
DO NOT TRIM LIKE THIS. A juniper is not a hedge and die back will occur if you prune all the tips in this way.
This juniper below has great amount of space between its branches, although for the sake of teaching, this is where you would trim if you were to remove a branch where growth was too dense. This causes minimal browning, and is a great way to thin out an area of growth. Cut flush with the stem.
The below picture shows two great things. One, it shows browning that occurs when cutting junipers. This is sometimes unavoidable, but it will be covered up in the coming weeks by new growth. The second point of focus in this photo is where I am cutting. This shoot has extended too far but is too hard to pinch. I try to avoid cutting the spiky needles on the stem, and cut back to the nearest buds. Again, some minor browning will follow, but that's OK.
The stem in the center of the photo is weak will probably not grow into anything useful. If thinning is carried out, this type of weak growth is the first to go. Cut back back to the brown stem.
Another Conifer Trimming Example (Cypress)
Make sure you're cutting back to a main branch or stem that is woody. The cypress can get quite dense, so this kind of thinning will be needed one or twice a year.
A technique that is not considered pinching or thinning is called 'needle-plucking'. It is done on conifers that have needles, like spruce and pine. The process of thinning involves removing needles from a stem. You can either remove old needles further down the branch or you can thin the newer needles. How much you thin and when is based on the time of the year, the tree species, and the trees health. Simply put, needle plucking is done to balance energy in a tree, encourage bud development, and allow light and airflow into the tree. It also makes wiring easier with less needles in the way. Thinning on pines is done with your fingers since the needles can be removed so easily.
Below is an illustration from the book 'Master Series Pine Bonsai'. Here they are thinning needles to redistribute energy around the tree, The zones they mention refer to different areas of vigour around the tree. Zone A would be a strong area of growth. Zone B, medium growth. Zone C, weak growth. By thinning stronger and more vigour areas of the tree, the weaker areas of the tree have a chance to catch up. Thus, balance is created.
Cutting back to a bud
One important piece of information that should be followed (especially with conifers) is to always cut back to a bud. If you don't cut back to a bud on a conifer tree, there is a chance that branch will die off as no buds with extend to replace it. Below you can see buds opening on a conifer tree. Trees will try to grow outward as much as possible, so most buds will grow from the ends of branches. If we let the tree have its own way then we would have a trunk, very long branches, and foliage at the end like a fan. This doesn't look good and results in a 'leggy' tree. We want growth as close to the trunk as possible, to do that, cut back to a bud further back on a branch.
Above is an example of a 'leggy' bonsai tree. This bonsai has long branches that have little growth close to the trunk. It just doesn't look right. With some clever design considerations, wiring, and patience, the bonsai will fill up with dense growth closer to the trunk.
Below is an example of a bonsai that has growth closer to the trunk. Pinching and trimming back to a bud is important.
Trimming a broad leaf
Further down you can see a picture of maple being trimmed. What you first need to know is if your broad leaf grows in an alternate or opposite fashion. Directly below you can see the two types. This is also a great time to explain 'nodes' and 'internodes'. Do you see the buds at the base of the leaf stems? Those are nodes. The space between each node is an 'internode'.
A maple growing in an 'opposite' fashion seen below. Whether your broad leaf species grows leaves in a opposite or alternate manner, you will still need to trim in the same place, and that is right after a node. Below you can see me doing just that. As for the cut itself, when making a cut, use sharp scissors and cut on a 45-degree angle. Aim to cut right above a leaf node.
Some advice on trimming. If you trimmed every bud as soon as it opened then the tree would never gain any strength. So instead, we allow the new shoots to extend before we cut them back. Different areas of the tree need to be cut back at different amounts. See the below for reference.
- Strong growth at the top of the tree - Allow 3 or 4 internodes to grow, then trim back to 1 or 2 internodes.
- Weaker growth at the bottom of the tree or in the centre of the tree - Allow 5 or 6 internodes to grow then trim back to 3 or 4 internodes.
We do this to allow weaker areas of the tree to gain strength, and to keep on top of stronger areas so they don't get away on us. Another great benefit of trimming the top more than the bottom of the tree, is that you naturally get a triangle tree silhouette! (which is what we always aim for)
Our trimming will also ensure the even distribution of energy around the tree. As you continue to prune, more smaller shoots will take their place. After a few months, a nice 'pad' of foliage develops. If it gets to dense, remove some stems. If you're aiming to grow certain branches bigger, allow the growth on the branch to grow wild and unchecked. The more growth on a branch, the more energy is receives and the thicker it gets.
Trimming a Flowering Bonsai
Your approach to trimming a flowering bonsai is a little different depending on the species. Some trees flower in winter, others in spring and summer. In all cases, wait until flowering has finished before trimming. If you trim a tree before it flowers, it will not flower as profusely as you are cutting the flower buds off the tree. For winter flowering trees, this means trimming after flowering in spring, up until late spring. Don't trim during summer though. During summer, the tree will be growing flower buds for next year, so these shouldn't be removed.
For trees such as the Azalea, flowers may continue to grow on and off year-round. This can make things tricky, so trimming right after flowering is your best bet.
This involves cutting larger branches and requires you to have a concave or branch cutter (if you have neither, a sharp pair of secateurs will do). As for the timing of hard pruning, not every tree is the same. Generally the best time to hard prune is in late winter or early autumn. It pays to do some further research on your particular tree if you want an exact time. Don't hard prune if you have been trimming your bonsai a lot this year. When hard pruning, don't remove more than one-third of the tree's foliage when pruning unless you know the tree and its species well. Pruning is a great way to reduce the height of your bonsai or to remove larger branches that are unsightly.
Below is an image of a branch cutter being used on a pine bonsai. I haven't used any other examples as it is more or less the same process. Branches can be removed using this tool or a pair of secateurs (a branch cutter leaves a wound that heals better). When pruning, make your cuts flush. Although, always research your bonsai species further before deciding to carry out major pruning. Maples for example, shouldn't be cut flush, but instead, you leave a stub as die back can occur. Simply Bonsai will always send a specific care guide with each tree telling you when and how to prune your bonsai.
Trimming & Pruning Guidelines
The general shape you are trying to achieve with your bonsai is a triangular silhouette where the top of the tree is highest. Using the picture below as your guide, you can see what kind of undesirable growth might need removing. Remember that the below are only guidelines. You decide what you want for your bonsai.
Wiring A Bonsai
Wiring is an important part of bonsai. A lot of people believe that bonsai is a type of tree and that naturally grows into a bonsai shape. As convenient as that would be, a bonsai is not a type of tree, but a normal tree that has been trained by various methods. One of those important methods is 'wiring'. Without wiring, the tree would grow where it wanted and without any resistance. When wiring, try to turn any straight growth into curves (this includes the trunk and branches). Old trees tend to have twisted trunks and branches, so we copy nature here. Wiring doesn't always need to be done though. In a lot of cases, the tree will look fantastic with only frequent trimming/pruning. But sometimes you may want to turn a trunk or branch into a more interesting shape, or make it straighter if that is your goal.
Wiring a bonsai involves wrapping wire around the branch or branch and bending the desired branch into position. The wire will hold the branch into position until eventually, the tree sets it in place. Wiring actually damages the tree in a minor way. Think of it as a minor fracture. Once the tree has repaired the branch, the wire can be removed and the branch will stay in place.
Start by taking a length of aluminium wire which should be roughly one-third the thickness of the branch that you're planning to wire. The length of wire you will need to wire a branch is tricky to gauge.
If you're wiring the trunk of a bonsai, push the wire into the soil at the base of the bonsai tree. Begin to curl the wire around the tree at a 45-degree angle. The gap between the wire should be just right. Too close and the wire will be too much, too far and the wire will have little effect. Once the wire has reached the top of the tree, you can cut the wire off. When trying to bend a trunk, you will need to be careful not to snap it. Bending a trunk can be tricky because this is often the thickest part of the tree. It is best to wire the trunk of a tree when the tree is still young and malleable.
As for wiring a branch, start by curling the wire around the trunk once or twice before proceeding to wire the branch so that the wire has a foundation. Once the wire has been applied, you can begin to bend the branch into position. Listen and feel for any cracks. If you hear a 'snap', you've gone too far! That's alright though! The branch will heal. If it has been snapped badly, you can use superglue to close the wound. This trick only works on branches smaller than the thickness of a pencil
You can also wire two branches with a single length of wire. Below is an image of how this is done. Note the different coloured wires for each wiring.
A very important point to remember is that your bonsai will not always look perfect. You must allow your bonsai to grow wild in between pinching, trimming and pruning. Constant fiddling will weaken your tree. You must exercise restraint and patience when practicing bonsai. The pictures of bonsai you see on Instagram do not always look as pristine as they do. The bonsai you see will need to recover its strength and grow strong again before it is displayed in a show next.
Reading about pinching, trimming, pruning, and wiring is a great start... Although if you really want to improve your skills, then I suggest you also watch videos, and make use of other channels of learning. There are many great websites and bonsai clubs dedicated to teaching bonsai. I would recommend looking up your local bonsai club as they often have monthly gatherings.
Thank you for taking the time to read my guide. I hope you enjoyed learning more about bonsai. Please reach out if you have any questions, I am happy to help.