Stressors in our bonsai

[Lazylightningny]

I did a little bit of thinking on this subject some time back, to try and eliminate stressors that are within my control. Careful observation of our trees and the environment should give us clues as to what may be wrong with our bonsai.

Here's what I came up with:

1. Water: too much, or too little.
2. Soil: too water retentive, not water retentive enough. Too much soil, too little soil. Soil particles too big, too small. Too much organic matter, not enough. This is a topic that has started a lot of flame wars.
3. Temperature: cold and heat extremes.
4. Pruning: root and foliage pruning, bare rooting.
5. Repotting.
6. Wiring.
7. Improper fertilization:
   • Over-fertilizing (root “burn”).
   • Under-fertilizing (inorganic medium has no inherent nutrients, therefore plant is unable to obtain nutrition).
8. Infestations: insects, fungal, bacterial/viral.
9. Improper use of insecticides, fungicides, and other “’cides.”
10. Position: shade vs. full sun; species specific needs.
11. Disturbance by, or browsing by animals.
12. Performing seasonal tasks in the wrong season.

We're able to control all these factors to some degree. We can't control the temperature, but we can use shade cloth in the summer when temperatures become extreme, and cold frames and other methods in the winter to protect from the cold. We can't control the rain, but some have built overhead protection to prevent unwanted rain from drenching plants (something I want to do in the near future). We can read the directions on fertilizers and 'cides so we use them properly. And so on.

Some of these stressors are seasonal tasks that we all must do. Pruning, wiring, repotting- these are the basic nuts and bolts of doing bonsai. Doing them the right way for each tree, and at the right time of year are imperative to minimizing stress on our trees.

I've only been doing this for 5 seasons. I don't have any honkin-ass bitchin bonsai that are enviable- but I will. I don't have a lot of money and I have no sensei, so I'm reliant on books, this forum, the internet, and common sense to progress. I consider all of you my collective sensei. My learning curve is long and steep, and I'm still killing lots of trees. However, if I can use the brain that God gave me (or what's left of it after a misspent youth in the 70s) and control these factors to the best of my ability, or at least minimize the stress they cause, I can possibly tip the balance between killing a tree and saving it. The rest is just time and species-specific experience.

 

[AZbonsai]

I would add growing zone issues. Mainly, trying to grow something that is not meant to be grown in your zone. You can create micro climates but they are difficult to maintain indefinitely. Besides that pretty good list.

 

[just.wing.it]

Yes indeed....I concur.
Good list!

 

[Carol 83]

That list kind of stressed me out

 

[Cosmos]

To what extent would you guys say that regular wind (let's say light to moderate, not a hurricane) is a stressor? Does it trigger any kind of reaction in the tree, be it a denser root system, stunted growth or bigger nebari?

 

[GrimLore]

To what extent would you guys say that regular wind (let's say light to moderate, not a hurricane) is a stressor? Does it trigger any kind of reaction in the tree, be it a denser root system, stunted growth or bigger nebari?

There is a few factors but here in Organic Substrate, on a board, secured to the pot it MOST assuredly produces much heavier stronger growth. The gentle swaying of the plants also greatly discourages fungal and some insect problems

Grimmy

 

[Lazylightningny]

To what extent would you guys say that regular wind (let's say light to moderate, not a hurricane) is a stressor? Does it trigger any kind of reaction in the tree, be it a denser root system, stunted growth or bigger nebari?

Wind can be a stressor in a very weak tree, by increasing water loss. For example, for a newly collected tree which has just undergone a very stressful procedure (loss of roots and root habitat), some bonsai practitioners will place the tree in a mist tent, which blocks the wind and adds foliar moisture.

Wind on a healthy tree can cause thicker trunks and that mountain windswept look that everyone loves.

 

[GrimLore]

Wind can be a stressor in a very weak tree, by increasing water loss. For example, for a newly collected tree which has just undergone a very stressful procedure (loss of roots and root habitat), some bonsai practitioners will place the tree in a mist tent, which blocks the wind and adds foliar moisture.

There is some good for that - I agree BUT I find it easier to just properly water and hand mist if needed rather then aerate a tent and monitor for insects, fungal problems, etc... Where I am it is far easier to properly locate whatever plant it is while watering, does not matter if collected or new from a grower and benefit from the air movement. Why? Up in the Northern parts we do not have the Equatorial Sun as do a lot of Southern States. Whole different set of rules, location, location, location

If however you do not have the time and are "growing" in Inorganics which most do not follow - well that is a coin toss - serious...

Grimmy

 

[sparklemotion]

Related to these two:

3. Temperature: cold and heat extremes.
10. Position: shade vs. full sun; species specific needs.

is season length. Trees that need dormancy can be stressed by a lack of chill-hours, even if the extremes are always within range. Same for tender species that need a longer growing season than higher latitudes can provide.

I also don't see any discussion of humidity.

 

[Lazylightningny]

There is some good for that - I agree BUT I find it easier to just properly water and hand mist if needed rather then aerate a tent and monitor for insects, fungal problems, etc... Where I am it is far easier to properly locate whatever plant it is while watering, does not matter if collected or new from a grower and benefit from the air movement. Why? Up in the Northern parts we do not have the Equatorial Sun as do a lot of Southern States. Whole different set of rules, location, location, location

If however you do not have the time and are "growing" in Inorganics which most do not follow - well that is a coin toss - serious...

Grimmy

I have never tried the mist tent, but I have seen it used online... Peter Tea used one for a large collected tree, I believe. I can't afford the luxury, so I put stressed plants against a north facing wall that has some wind protection from 3 sides.

A lot of these things we say ("do this, do that") are tidbits passed down that may have no merit in science. I haven't been at this long enough to say with certainty that any particular piece of advice works. Is it best to keep a stressed plant out of the sun and wind? Or is it better to keep it in the sun? There's probably no good advice, because it depends on species, USDA zone, climate, molecular changes in the plant, and a host of other factors. For the most part, I'm just spewing the same advice given by others. The people who have grown hundreds of same species over decades really know their stuff, but I'm still learning basics. This list is one way for me to, cerebrally at least, get a grasp on what is going wrong with the failures, and what went right with the successes.

 

[Lazylightningny]

Related to these two:


is season length. Trees that need dormancy can be stressed by a lack of chill-hours, even if the extremes are always within range. Same for tender species that need a longer growing season than higher latitudes can provide.

I also don't see any discussion of humidity.

I think this ties in well with what @AZbonsai said above about growing zones, or what we call USDA zones in America.

What would you like to say about humidity?

 

[M. Frary]

What would you like to say about humidity

It makes me moist.

 

[sparklemotion]

What would you like to say about humidity?

Just that it is another factor that can affect the vitality of bonsai trees, and is a tricky one to compensate for. If you're trying to grow a rainforest species in the desert, watering more will only get you so far.

 

[Cosmos]

So, from your experience, are these statements true:

Anchoring the tree in the ground will give you more taper, buttressing, and a better nebari, due to the stress fractures that will form from the wind waving the whip. Unstaked trees in studies at UC Davis have grown larger and stronger trunks than staked ones.

Let them grow wild to about fifteen or twenty feet where they can wave in the wind. This will develop enormous buttressed trunks in about five years since they are anchored in the ground.

From Developing Large Trunks for Bonsai, by B. Walston

 

[Anthony]

Hackberry - Celtis l, in the tropics cannot handle full sun and wind.
Winter - Fridge.

Stay With - NATIVES - until you master growing [ 2 to 5 years of hand watering
not hose or automatic system ] remember this effort s based on personal
observations.

Used to be 2 weeks in bright light after repotting.
Somehow it became 1 week.

Test on a local willow ficus, pulled up after a week showed no new roots.
Second week roots galore.
Ficus is one of our fastest to recover and handles abuse well.

As to soil - keep it SIMPLE - we use only 2 or 3 ingredients.
2 inorganics, one able to hold water in itself.
1 organic [ if you use organics ]

Know you can calculate you water holding capacity -

Peatmoss - holds 15 times it's weight in water

Compost - holds 20 times it's weight in water.

So for us - humidity from December to May/June can go to 45 %
humidity in sun.
Back up to 70 % by night.
June to November ----- 6 to 8 to 9 inches of rain.

So 3 parts organic to 7 parts inorganic [ size 5 mm ]
is our max for holding water.
Can go as low as 1 part organic to 10 parts inorganic [ eg. Ficus ]

Also if we need to hold more water - addition of an inorganic
that is porous, substituted for the non porous inorganic.

Pots can be porous and non-porous.

Bare rooting takes away about 2 to 3 months of aggressive growing.
Factor that in.

Plants should not touch each other.

Experience = 39 years of growing, experimenting and research
and hand written notes from reading at the University Library,
not Google.

Most problems will be soil/watering = stress = insect / fungal attack.
And too much fertiliser - 12 N seems to be max and 2 P or 2 K
Good Day
Anthony

 

[Lazylightningny]

So, from your experience, are these statements true:





From Developing Large Trunks for Bonsai, by B. Walston

I've read this also. I have not done any experiments in this area, but since UC Davis is a reputable university (if a 'tad' liberal), I believe it to be true.

 

[Lazylightningny]

until you master growing [ 2 to 5 years of hand watering
not hose or automatic system ]

Why do you say hand watering and not hose watering?

Most problems will be soil/watering = stress = insect / fungal attack.

I agree with this 100%

 

[Anthony]

Hand watering allows you to pay attention more intimately
to your trees.
Deeper bond.
Good Day
Anthony