This article is about the maintenance of the Pinus sylvestris and the Pinus mugo, but the techniques I will describe here can, with some small adjustments, also be used for, Pinus nigra, Pinus uncinata or Pinus ponderosa.
Some Notes about Climate
First, before I start:: I know that what I’m going to explain in this article works because it is what I do successfully with my own pines. But, I know not everybody lives where i live, and that climate and seasons differ greatly around the world. However, I do believe that the techniques remain more or less the same, so you only have to adjust the techniques to your own local situation! Best thing to do: is to ask a knowledgeable bonsai colleague that lives in your aria about things like local growing or weather circumstances.
I kept it all as basic as possible, and straightforward so that everybody will be able to understand it easily, so they will have no problem applying the techniques I describe on their own trees. All the techniques I describe must be done every year (except on a young tree that needs to grow), There are many different ways to balance your pine and for needle reduction, etc. I think that the ones I describe here are a good place to start for any novice.
Pine Growth Habit and Energy Zones
Before I can go in to the energy balancing techniques, I must explain the different energy zones of the pine tree.
Pines generally grow irregularly upwards in search of the sunlight and when they mature they will grow more horizontally. If we look at the pin tree as a whole, we can tell that there is a significant difference in growing strength between the outer regions of the branches/tree and the inner parts of the branches/tree. This difference is a result of the outer parts receiving more light and air than the inner parts, which mostly have to live in the shade of the other branches that block out most off the light. Another factor is the pine’s natural growth pattern: favouring the branch tips and apex of the tree.
As with all living things in nature, only the strong will survive! Those strong zones play a much bigger part in the photosynthetic energy process than the weaker zones; therefore, they are more important for the survival of the tree, so off course the tree needs those parts to flourish and will their for send more energy to those all important zones. The weaker zones as a result will get weaker and weaker and eventually die back. This is a natural process, so don’t worry: with the techniques I will explain, we are going to balance every part of the pine, so that ideally every part of the tree becomes equal in strength.
Care and Maintenance
Pine maintenance is all about mastering the techniques for balancing growth energy within the tree. Like with all pine bonsai, candle pinching, candle removing, needle plucking and soft and hard pruning are very important to keep the tree healthy and well balanced.
So lets pretend we are starting on a more or less virgin specimen or neglected tree. First, you must look closely to your tree and learn to recognize the difference between the strength zones. The outer regions of the branches on the tree will most likely be stronger than the inner parts. This is easy to see if you examine the longer needles and the healthier growth of the shoots, etc. So, now that you know how to differentiate the strong parts from the weak ones! This is what you should do!
With candle pinching we take the first step in balancing the new growth! By pinching the candles in the strong zones in springtime by 2/3 up to 3/4 of their length (depending on the strength of the candle). On Pines with thin candles like the Pinus sylvestris this pinching is easily done with the nails of your thumb and index finger (see drawing below).
On Pines with ticker candles like one the Pinus Mugo , this is best don by holding the candle at its base with your index finger and thumb of on hand, and then pull/break the candle off with the index finger and thumb off the other hand. Try to do this carefully in one clean break. By doing this we considerably slow down the growth of those stronger candles. But if all other tasks this year are performed correctly, next year you already have to do much less spring pinching because the overall balance off the tree will already be much improved. Remember: only candle pinch strong candles and leave the weak ones alone, even in the strong zones!
The exact timing for removing the candles is crucial for the result we’re after. If you remove them to early in the season, they will not yet have grown enough to achieve the result you want, because as a result: the new buds will grow back too strongly. If you remove them to late: the new buds will grow back irregularly, some weak and some strong. The also will have a too short growing season ahead of them. So, when is the right time for candle removing? Well, you will actually learn this from directly observing your own tree, but as a rule you can say that the right time is when the needles on the new candles are opening out, and start feeling a bit harder when you touch them.
When this time has arrived, we first remove the complete candles from the middle strength zone with a sharp and clean shear (see drawing above).
After 10 to 14 days (depending on how warm it is where you live) you remove the complete candles from the strong zone.
Do not touch the weak candles, even in the strong zone!
Tip: Cut the candles as straight as possible just a few millimetres above last year’s needles (see drawing above), if your cut is not straight, the new buds will be off differing strength.
Tip: When your Pine reaches a state off overall matureness, were in the branches and foliage are in good balance, and you have reached your objective goal in your design. You can decided to maintain the balance in your tree by only pinching the candles to balance them. Removing the hole candles every year is very stressful for a Pine and unnecessary. You can always start doing it again when the tree grows out off balance or shape.
Because the tree is in the middle of its growing season when the candles are removed, it will respond quickly with an abundance of new buds around the wound left from removing the candle (see picture above), and it will all so trigger the growth off dormant and weak buds along the rest of the branch; (see picture below) again depending on where you live this will happen in between 2 and 4 weeks. And because we have given the weak zones a big head start on the strong zones, we have balanced the energy distribution to the different zones a great deal already.
Tip: On Mugo pines that are in their early stages off development it is a good idea to let the new candles grow a bid longer, this way there will be much energy going through this branches. If you than cut the new candles off or even cut back lower on the branch into last years growth, or if the tree is very vigorous into the growth from 2 or 3 season before, the tree will respond with new buds all along the branch.( see picture below)
Later, when the new buds have swollen enough, you can remove if necessary some buds very carefully without damaging the buds you want to leave! Leave two strong buds on the shoots of middle strength, and two weak buds on the strong shoots. By doing this we have balanced even more the energy distribution through the entire tree. And you will see that next year the tree will need much less work to maintain its balance.
Needle Thinning on Pinus sylvestris
Plucking needles is the last main task of this growing season, if this task is not done, all the previous work will have been for nothing. The technique off how to do this on Pinus sylvestris or Pinus ponderosa is diverant from what we do on the Pinus mugo variety’s! I will first explain how it should be don on Pinus sylvestris. Fewer needles means less energy transport to the shoots.So, in the fall we pluck away all the old needles to let in light and air to the inner weaker parts of the tree. Try to pluck the needles off in the direction they are growing, then there is less chance of damaging the bark. I actually prefer to cut those old needles away with the help of a sharp and clean shear just above the sheath that hold the needle bundle. My experience is that leaving those sheets promotes more back budding than if you pluck out the needles, which will often damage those sheets from witch new buds will grow. The little stumps you leave by cutting don’t look very appealing, but they will fall off eventually and in this early stages of the development of the tree you should not let the appearance of the tree concern you too much.
At the end of the Fall, pluck/cut away needles from this year’s growth on the strong shoots, leaving 5-6 pairs.
Do the same thing two weeks later on the shoots of medium strength, leaving 8-10 pair of needles. Again do not touch the weak shoots!
Needle plucking is stressful for the tree, so should only be don if the tree is healthy! As before, with all the other techniques described here, look carefully at what you are doing, comparing one shoot to another. Think about what you are planning to do step by step, and remember or write down what you did and take photo’s, so you know next year if what you did was right for that particularly tree, or if you should change anything!
Tip: On any two needle Pine, If you have trouble plucking a pair off needles by hand without damaging the sheaths, try to pull out one needle out at a time with a little twist between your fingers- giving the needle a quarter turn as you pull- this will work most off the time.
Tip: When you start working on a Pinus sylvestris or Pinus ponderosa there might be a great difference between the middle zones and the strong zones; in that case, you can also combine candle cutting with needle plucking. When you remove the candles from the middle zone, you also remove needles from the strong zones. This will slow down the growth off the strong shoots even more. If all goes well, this is only necessary in the first year of working on the tree. The next year the difference between the zones will be much less obvious.
Needle Thinning on Pinus mugo and mugo variety’s
In early stages off the development of a Pinus mugo, the needles off previous growing seasons are better left on the branches. Successful back budding depends on those old needles, because from their base the new buds will grow. In later stages off the development of the tree, when there are enough candles to work with, you can start cutting the older needles off.
On Mugo pine you never pluck needles! Not even last year’s needles! You always cut them with scissors, leaving 3 or 4 millimetres off the needle above the sheaths. By doing it this way there will be much more back budding among those needle stumps you left. Even among last year’s needle stumps, because they are still receiving energy before they dry out and fall off. You can start removing needles off last years growth, only on a established Pinus mugo just like what you do on a Pinus sylvesris like I described before , to balance the energy and to keep the tree in shape.
Although Mugo’s and Mugo variety’s are stronger than other two needles pines, the booth react well to pruning, even hard pruning, when this is done in late Fall/early Winter, it will even react with back budding even on older branches.
Prune away all the growth you don’t need in the strong zones, but be careful with what you prune in the weaker zones. When you prune away a thick branch, it is always better to leave a stump so that it has the chance to dry back naturally. That way, the tree has time to find a new path around this large new interruption. This way there is less risk of losing a branch (or worse) right above the branch you cut off. After the stump has dried out you can always use it as a jin or remove it entirely, if you do decide to remove it you can carve it and the wound will heal up more quickly and more naturally. Again only perform this heavy branch pruning on a healthy tree, and even then, not every year.
Feeding a tree is very personal, but this is what and how I feed my Pines.
Especially with feeding your bonsai count: look carefully at how your bonsai reacts to: when, what and how much nourishment you provide it.
I start the feeding cycle in early spring with a very mild foliar fertilizer based on algae. When the temperature gets a bit higher I give a feeding of in water-soluble liquid fertilizer. Unlike solid fertilizer that only is useful if the ground temperature is above about 17 degrees, this liquid fertilizer will get in the tree’s system even at lower temperatures.
When the temperature stays high enough for a long period and before the buds start growing too strong, I will give a feeding of water soluble “Super Bio Gold”. During the period of growth of the candles I don’t feed at all, except if the tree is in the early stage of training and need growth or if i plane to cut back into old growth during the growing season!
In early Summer after candle cutting, I give organic fertilizer. During the hottest weather of summer I don’t feed at all: I will start feeding again in late Summer when Pines start their second flush of growth. The roots, especially, will grow a lot during this period. That’s why this is also a good time to collect or repot pines; they only need to be protected from strong sun for a couple of weeks and given frost protection during the winter period.
During the fall I feed two to three times with nitrogen-free in water-soluble fertilizer (PK fertilizer).
Tip: Don’t use Superthrive on your pines; it is harmful to the micro-organisms in the soil that the pine needs to survive!
Repotting a Pine
Timing the repotting: Right up to the time I started on this article: I always repoted my pines in late Spring early Summer when there was obvious swelling off the buds and there was no more real chance off heavy night frost. This time works fine for me up to now, bud I’m getting more and more convinced it is saver to repot in July/August just before the annual root grow period starts. The Pine is then at its strongest and will recover quicker from the stress that repotting always brings along. The temperatures are just right as well fore optimal recovery. So I will change my own routine to this new dates and see what happens?! I will: Off course write my experiences down in this article!
What to prune: be careful with root pruning. Long and thick roots are useless and should be cut back to just before the point where there are healthy feeder roots ( yellow/white tipped ). Doing this will redirect the energy flow and the tree will react by making additional feeder roots, just as cutting a branch promotes the development of small twigs. So leave as much as possible of the feeder roots when you repot.
Cutting large roots must be done in several repotting sessions, so the thick roots can grow more of those all-important feeder roots. Then you can safely cut it back even further the next time it is repotted. Take your time, all this will result in a compact root system, full of feeder roots.
Old soil from collecting or nursery shoot be removed as much as possible when the tree is repotted for the first time. Especially mountain soil can become as hard as a rock, so water cant run through and roost cant grow in it.
Frequency of repotting: Don’t repot any pine too frequently, no pine is a fan off repotting! When a Pine is potted in good soil once every 3 years is more than enough. If the Pine is more established, once every 5 years is even better. You must remember than every time you repot a bonsai, you will rejuvenate it and it will: (after a period of standing still and recovering) react with a lot of root growth, and this will cause the new candles to grow too strongly and irregularly again. So the cycle of balancing the energy of the tree start all over again. This is an especially important point to consider when you plane to show your Pine bonsai in its best condition.(well balanced small needles all over the tree and a mature looking ground cover.)
Inoculation with Mycorrhizae: Always mix a portion of your old soil medium into the new mix, this old soil is full off important Mycorrhizal fungi that Pine needs for its survival. Remember that if you don’t put this in, that it can take up to 2 years before there is enough new Mycorrhizal fungi in your fresh soil mix for the Pine to be happy again!
Watering after you repot: Keep in mind that a freshly repotted tree uses less water, so let them become a bit dry before you water them generously.
Misting your Pine tree after repotting is always helpful for the trees recovery.
Start fertilizing after you can see the tree is recovered from the repotting and shows signs off growth.
Soil for Pines
I use a mixture of Akadama, Kiryu, Bims (a porous lava stone product). With Mugo Pine I add even more Bims to this mixture, because of its capability to retain water without becoming sticky or losing its shape (the soil needs to stay loose and porous). On freshly collected material i also add pine litter (compost) to promote the growth of Mycorrhizal fungi, which all pines need for their survival. This mixture works fine for me because I live in Northwest Europe were it rains a lot, so I need this kind of soil structure. I am also in a position to water the trees when it is very hot ( this soil mixture dry’s up quickly), sometimes even twice a day! You off course must adjust the soil mixture to your own weather conditions, if you are not sure: you can find some advice and help from a local knowledgeable bonsai enthusiast, bonsai club or even on the internet, this should be no problem.
Do not let pines dry out completely, not even for trying to reduce needle length; you will get those smaller needles from using the proper techniques I explained. And when you water: water thoroughly! With the mixture I use there is almost no way you can over water the tree. Although Mugo and sylvestris pines can tolerate much water, it is never good to let them stay too wet for too long. When it rains for a days on end, tilt them to one side with a piece of wood underneath one side of the pot, so the excess water can run of and out of the pot. Even better: put them under some shelter or cover them up with a plastic sheet. Also, you must remove all fertilizer cakes from the soil surface when it rains for along time, to prevent root burn.
This is best done from Fall to early Winter when we have plucked and thinned out the tree. You can get a better view of what you are doing, and there is less change of damaging the new buds.
Be sure to check wires frequently, especially on young and rapidly- growing pines.
On two needle pines you can wire the branch tips out level with the ground because the tree is strong enough to force the new bud growth upright.
I always give my pines exposure to a period of light frost. This way the tree knows it is time to prepare for winter. I keep them as long as possible out in the open air but when the temperature drop below freezing, I will put them in a plastic greenhouse where the temperature never drops below 0 degrees Celsius (32F). During the daytime, if the weather allows it, you must ventilate as much as possible, and be careful that the temperature does not rise too much when the sun hits your Winter shelter.
So, there you have it! i know this is just a basic overview of Mugo and Sylvestris Pines maintenance, but I still hope it will help you to take proper care of your own pine bonsai.