Consistently killing conifers. Confused.

[River's Edge]

This is the conundrum I came up against--I know that you're not supposed to bare root conifers because of the micorrhizal relationship, but if you're not supposed to bare root it, and not supposed to leave nursery soil in there, what do you do?

It is tempting to give a set of instructions because that is what is expected and it should be simple, right!
Well it is not always simple and there is no one right way. It depends on the tree's condition, It depends on the condition of the roots, It depends on the current soil and the change you wish to make to the soil.
Re potting is one of the fundamental skills required for successful bonsai care! When you watch a video the steps taken are basically what is applied in those circumstances for that tree, or a demonstration of basic principles that need to be adapted for specific circumstances. Conifers require more care and patience, they do not respond as easily or quickly from root work when compared to deciduous.
Having said that I will give you a general approach to the circumstances you are likely facing.
First situation
Acquiring nursery trees that are root bound and have been up potted for several years. They are typically in organic soil with tangled root ball and housed in narrow deep black plastic pots. You have been working with juniper as I understand it from your notes! Juniper react strongly to extra root pruning so it is important to balance your approach. In this case I advise the following.

Organise the following materials. Chopstick, scissors, bonsai soil you wish to use and a variety of pots typically wider and a bit shallower than the nursery pot the tree came in. The exception will be if you wish to grow out the tree and then you may wish a larger container and that is a separate process.
* Misting bottle to hydrate the tree and exposed roots during re potting! ( stop and do this every ten to fifteen minutes)
Adapt you approach if the you observe the following.
A. weak areas of root growth or areas of damaged roots ( in this case deal with this areas first counting the area as part of the allotted amount of work each session)
B. lack of feeder roots, excess strong roots with lots of feeder roots on the ends ( cut fewer strong roots, fold under those possible and wait for the tree to strengthen again before dealing with more stronger roots. If cutting a stronger root leave some side roots on the portion remaining, do not cut all the way to the base. With experience you will adjust your level of comfort and understand how much is too much! In the beginning err on the side of caution.


1. Dig carefully around the base of the tree and remove the soil down to the level of the main lateral roots coming out of the trunk. You are establishing where the base of tree is and exposing the nebari. When you are doing this use a chopstick and pull it outward from the trunk to the edge of the root ball slowly to gradually straighten small roots and remove the soil. Stop when you are at the level of the nebari. This prevents you from removing too much soil from the bottom first when the tree may be buried deeper in the pot.

2. Turn the tree over and using the chopstick carefully work out the bottom roots and soil for the bottom 1/3 of the remaining root ball. cut off the thick downward roots. When cutting the roots go back to side roots on the thick root wherever possible. leaving the side feeder roots intact. Leave finer flexible roots intact and to fold under when repotting. Set the tree back upright!
3. Using the chopstick with a slow outward and downward motion draw out the roots on the outside 1 to 2 inches perimeter. removing the soil and teasing out circular or longer roots. These roots will be cut to fit into the chosen container.
4. So for this first repotting stage you are removing soil down to the nebari. removing soil from 1/3 of the remaining rootball at the bottom and some off the sides.
5. Choose a container to fit the remaining root ball after these steps and prepare it for repotting. You want a reasonable fit with the depth to have some soil below the tree and approximately 1 inch around the perimeter. Tie or wire the tree in firmly when repotting, this is an important step so the new feeder roots are not constantly damaged by movement in the early recovery stages.
5. After repotting thoroughly water the tree until the water runs clear out the bottom, place in partial shade for three or four weeks. water when the tree needs water, but do not let it dry out and protect it from drying winds.

The next two repots will be 1/2 HBR, one side at a time. The process will be completed by the third repot and future repotting will be much simpler and involve different steps as the root ball changes to a more refined mass of feeder roots over time. ( for collected trees or finicky species I often divide this portion into three stages dealing with weak segments first) This is a slow but safer process I prefer for Mountain Hemlock and Shore Pine.
Typically, if the tree responds very well, one can complete this process over a period of twelve to fifteen months. First step in March/April, Second step in August/September and the last step in March/April. However juniper can be finicky and sulk after repotting so the tree may respond slowly and the process could take three years. ONE OF THE MOST IMPORTANT THINGS YOU NEED TO ACCOMPLISH IN BONSAI IS ADAPTING THE ROOTBALL FOR LIFE IN A BONSAI POT, THIS TAKES TIME AND IS THE FOUNDATION FOR A HEALTHY TREE TO DEVELOP AND REFINE OVER TIME.

Please note: I deliberately did not state what soil mix you should use. I am not aware of your climate or watering routine. My personal choice would be APLG. Akadama, Pumice, Lava, Granite. I would vary the percentage of akadama based on the climate. For medium and large trees I use a thin drainage layer of larger pumice one or two particles deep. The particle size of my mix is consistent for all components not that much smaller than the drainage layer so there is no concern over " water table". I prefer the extra air space for gas exchange in the bottom layer and most trees do not like to sit in water. For this reason I also select pots or containers with adequate drainage for healthier trees.
For those inquiring minds I use the granite grit for additional stability as pumice, akadama and lava are lighter components. Organic fertilizer is my go to for this inorganic substrate.

 

[hinmo24t]

Thanks for the quick reply!

1. During the summer I water daily, unless we've had rain that day. I haven't checked it in a few days, since we've had consistent rain every single day for a week straight. Yesterday was the first dry day, so today I watered.
2. I tried to disturb the root ball as little as possible, only teasing out the roots and knocking out enough old soil to get it comfortably in its new pot. Otherwise, as normal. Wire mesh over drainage holes, mound up soil, put tree in, tuck roots down with chopstick, backfill and poke with chopstick until all the voids are filled.

im in MA...we had that heat yesterday as well. thats the type of heat and humidity we get in summers that
gets me up at 6am on weekends and get my shit done before noon - get in AC for heat of day - then back out in the evenings

in summers i water my kotobuki jap pine about once every 3 days if theres been no rain or w.e.
if its outlying hot/humid/windy ill water it regardless

otherwise it falls into the 'a bit less of water than most others' category, along with bougainvillea
juniper chinesis. i water on a schedule and have had decent success with what ive been maintaining a few seasons,
despite the notion (not a bad notion) to water when they need it. my life is on way too much of a routine/schedule for
anything otherwise.

before/after work i water in summer and 75% of my collections gets daily water while reminaing 25% fall into every other or every 3 day, rain factored out

 

[ManSkirtBrew]

Wow, thank you all for the kind and thorough replies. This is such a nice forum

my trees get water at 8 am and again in the afternoon around 4pm. the morning is for breathing, the afternoon is for cooling the roots. try making a fence that blocks western sun to get shade if you cant get 2 waterings. i always lift my trees and check the pots if they need water

I'm clearly not watering my conifers often enough. It's only this year that I switched to a mostly inorganic, fast-draining bonsai soil, so I'm still learning. The sphagnum moss on top was an effort to keep moisture in, but it can only help so much.

Exactly WHEN did you repot? Was this shortly (1-2 weeks)after cold of Winter was past OR was there any hard freezing after repots?

I just checked my records and it was April 11. Later spring than I thought, but after any hard freezes.

Too early! Too Spring! I haven't had a conifer die on me since repotting the first full moon after the summer solstice.

I've read this advice from you before, and promptly forgot it when spring rolled around. I'll try again this year!

You want to do it in spring just as the buds begin to swell when it is warm enough to avoid freezes but still cool during the day.

...which directly contradicts @sorce one post above. As I just found out above, I repotted on April 11. I'm in New Jersey, growing zone 6a.

If anything, chop of the bottom of the rootball, leave the vast majority of the soil in place and plant in a wider, shallower pot, allowing feeder roots to grow sideways into the new substrate. Subsequent repots will allow for nursery soil removal in stages with a healthier rootball to fall back on.

This is actually what I did. My first repot was basically a slip pot into a wider container, but cutting off maybe 1/3 of the bottom of the rootball. I waited two years before doing this repot, and the tree seemed healthy and happy when I did. But being a relative newbie, I may not fully understand what a root system ready to repot looks like vs. one that needs more time.

Monitoring your trees daily and responding accord to what you see. If I have rainy weather, I still water my trees unless I get half an inch of rain or more in 24 hours.

Yes, I definitely have to do more adjusting to using mostly inorganic soil. It's definitely not as forgiving of a day or two of neglect.

 

[ManSkirtBrew]

it should be simple, right

One might think

Thank you for this tremendous reply. I'm going to ask some questions to make sure I understand.

For this first repot, we're basically leaving the core of the nursery soil undisturbed, only clearing down to the nebari, and a few inches around the sides and bottom. Will I have to be extra vigilant about water penetration, since I'll have lots of drainage around the outsides and not the inside? Or are we encouraging feeder roots to grow into the well-draining bonsai soil?

I've clearly been too cavalier with my repots. It's not just about waiting a few years then going for it. Watching videos of people like Peter Chan make it seem so simple, but it's easy to forget the decades of experience he has.

 

[River's Edge]

he reason you can't find solid advice that actually works in spring is because it's too "roll of the dice".
Last year's work matters, winter area matters, fert, water, pot size, local micro clime matters

If it matters, it matters regardless of the position of the stars or the roulette wheel!
I agree, the explanations require what to do when you find what matters. before that it helps if you can recognize what matters.
During the natural cycle of growth and climate their are typically two periods of time when root growth is stronger. Early spring and late summer/early fall.
The key difference is that the growing season is much longer after early spring than it is after late summer/early fall.

One can be successful repotting during either of these windows of opportunity with the correct techniques. The first window of opportunity in the early spring is best suited for those situations where a longer recovery period would be beneficial.

The "roll of the dice" exists with the human element of understanding and application of knowledge. Those who understand what matters and can interpret what matters can use either period of time successfully! As far as that goes with the proper aftercare and resources the window of opportunity becomes almost endless.
The lack of written explanations may reflect the detail required to cover all the possible situations, carefully enough!

 

[River's Edge]

One might think

Thank you for this tremendous reply. I'm going to ask some questions to make sure I understand.

For this first repot, we're basically leaving the core of the nursery soil undisturbed, only clearing down to the nebari, and a few inches around the sides and bottom. Will I have to be extra vigilant about water penetration, since I'll have lots of drainage around the outsides and not the inside? Or are we encouraging feeder roots to grow into the well-draining bonsai soil?

I've clearly been too cavalier with my repots. It's not just about waiting a few years then going for it. Watching videos of people like Peter Chan make it seem so simple, but it's easy to forget the decades of experience he has.

Yes watering needs to be adapted for mixed substrates. Check that both the centre core and outside are receiving proper levels of moisture. Because the water can run through the outside free draining mix easier it can be helpful to submerse the pot in water for ten to fifteen minutes if you find the centre portion drying out. Check it first though as it can retain more moisture than the inorganic substrate. Remember this is for a few months of adaptation in certain circumstances not a regular repotting process.
Yes you are encouraging feeder roots on the side and bottom during the first stage of repot. And you are removing or shortening some stronger roots from the bottom, encouraging bifurcation and more feeder roots on the remaining stronger roots that were cut.

 

[sorce]

The key difference is that the growing season is much longer after early spring than it is after late summer/early fall.

This isn't always true.

My first green starts in a 2 month window.

The key difference for me is it's easier for them to adapt to fall cold setting in, then cold returning in spring.

"Early "Spring" may make that true, but I can't roll dice through that window.

Sorce

 

[River's Edge]

've clearly been too cavalier with my repots. It's not just about waiting a few years then going for it. Watching videos of people like Peter Chan make it seem so simple, but it's easy to forget the decades of experience he has

The videos typically show what was done in a particular circumstance. frequently the attention to detail and interpretation of the material is not included in the explanation. Better presentations will include what the practitioner sees, how it is interpreted and what steps the practitioner takes to adjust to those circumstances. Most importantly will be a clear explanation of what the basic circumstances are to begin with.
Condition of the tree?
Stage of development?
Previous work done?
Particulars of this species?
What are the immediate goals for the tree?
What are the long term goals and the stages to accomplish those goals. Along with appropriate timing.
All of this introductory information is important! It matters.
Forget the smoke and mirrors of gross over generalizations.
ATD, attention to detail, work within the natural growth cycle, take your time. Begin with thorough preparation but be ready to interpret what you find and act accordingly. It is not voodoo, it is correct application of technique at appropriate times.
I would suggest seeking out an experienced teacher and take part in guided practice based on the tree in front of you! have some one show you healthy and diseased roots, how to prune a thick root, where to cut back to, which ones need sealing and which ones don't. When you can proceed quicker with the process and when it would be best to slow down the process.

 

[River's Edge]

adapt to fall cold setting in, then cold returning in spring

How so, Frost is more difficult than Snow? Not sure I understand! Multiple trips as opposed to one? The longer growing season is still a longer growing season as opposed to dormancy.

 

[CWTurner]

I'm just a hack when it comes to finishing bonsai, but isnt anyone concerned with @ManSkirtBrew feeding every week?

Does he do the same with his deciduous trees? Organic fertilizer?

Just a thought from a 1-2 times per year fertilizer.
CW

 

[penumbra]

I am sure that there are people who re-pot any time of the year and if they are experienced enough, their results will show. Of course there are degrees of re-potting from slip potting to bare rooting. As a retired nurseryman, almost all of my serious re-potting was done at the end of winter. To this day I will always prefer planting temperate zoned plants when they are dormant.
One size does not fit all, whether it is the planter or the plantee.

But back to the op, if you have problems with a specific type of plant, learn first to keep the plants alive before seriously considering making a bonsai of it.

 

[sorce]

How so, Frost is more difficult than Snow?

In that snow is insulating, absolutely.

In spring, once we remove them from frozen grounds, which is the only place they should be, that ground ain't warming up until after the last of the cold.

That leaves is with nowhere safe to replace them to, especially not the colder and still more frozen shade.

Safe after heat (not here) after the summer solstice, they will still be plenty warm, then bedded down on warmer ground, that won't get cold for as long as it takes it to thaw in spring.

That is a much safer place to continue to grow roots well beyond the time I'm going to dig em up to check again.

Sorce

 

[ManSkirtBrew]

Does he do the same with his deciduous trees? Organic fertilizer?

He does, and has excellent results with every other kind of tree.

I'm using liquid ferts and not slow release. Much of the advice I've read on here includes "fertilize heavily", so I've just been following the label instructions on these two products, and alternating them week to week.

The Dyna-Gro recommends:

Application Rates​

• Maintenance: Mix ¼ – ½ tsp. per gallon of water with every watering.
• Production: Mix 1 tsp. per gallon of water, once a week.

And the Neptune's Harvest:

House Plants: Use 1 tablespoon per gallon of water. Feed every 1-2 weeks. Do not over water.​

 

[Paradox]

I just checked my records and it was April 11. Later spring than I thought, but after any hard freezes.

I think your timing was OK.
From other things you've said, I think this might be a watering issue

 

[Kanorin]

I think the best advice I can give is to get someone local and experienced - from a local club or something - to come over and take a look at the tree and (if you decide to repot or biopsy at that point) the roots and stick their fingers in the soil to get a sense of how wet the soil is when you typically re-water.

The reason I'm emphasizing someone local who can put their eyes on it and stick their finger in the soil is because there have been a dozen people giving different advice here...and each of those pieces of advice is probably correct if you use it in their local climate and the soils they typically use. But here you have a juniper that has half or most of it's roots in nursery mix and the rest in Bonsai Jack soil

If I had to guess, the nursery mix part of the soil is staying too wet, and not drying out enough between waterings. This causes a lack of oxygen for the roots.
FWIW, I water my junipers and JBP about 1/2 to 1/3 as often as my deciduous for a similar sized tree with similar foliar mass.

 

[Lorax7]

Apologies if someone else has already mentioned this and I missed it: Are you sifting your soil right before use? Even good bonsai soil mix can be too water-retentive and have less than ideal drainage if not properly sifted to remove the finest particles. Many other factors at play and this is a small one, but nonetheless worth mentioning.

 

[canoeguide]

Yes, I definitely have to do more adjusting to using mostly inorganic soil. It's definitely not as forgiving of a day or two of neglect.

Inorganic substrate isn't usually forgiving of neglect, but it is forgiving of overwatering. It provides air exchange to the roots that aids growth and prevents root rot. It takes most of the guesswork out of watering, so long as you never let it dry out.

From everything you've posted in this thread, I wonder if the adjustment from nursery soil to inorganic mix, and a failure to adjust watering habits to accommodate it, is the culprit.

 

[Walter Pall]

Stop fertilizing you conifers!!! You are overfeeding them, They get weak and some sort of disease kills them .Do not fwetilize them until September. Then only half of what you did before. Next year feed about 26 % of what you are used to.

Fertilizing should not be called 'feeding' because it is NOT. It is adding a few minerals to the water. If in small doses they are beneficial. In large doses they can become toxic quickly.

 

[Paradox]

Yea I have to agree with Walter on that one. I think you are fertilizing too much.

I used to use Dynagro and I now use Neptunes Harvest
I fertilize once a month and except for Japanese Black pine or young trees in development, I dont fertilize until later in the summer after the new growth has hardened off.

 

[ManSkirtBrew]

From everything you've posted in this thread, I wonder if the adjustment from nursery soil to inorganic mix, and a failure to adjust watering habits to accommodate it, is the culprit.

This is my feeling too. And also still learning how to care for confiers differently from my other plants and trees.

Fertilizing should not be called 'feeding' because it is NOT

Can you tell me what feeding is, then?

I dont fertilize until later in the summer after the new growth has hardened off

This is the first time I've heard this, but then I'm also conflating feeding and fertilizing, apparently.

Jeez I'm learning a lot in this thread!