Was wind stagnating my growth?

pandacular

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I have had my juniper (Juniperus chinensis 'Old Gold') on the corner of my rooftop, about 4 stories above street level. Throughout the season, it grew very little while my other trees were often exploding with growth. Initially, I chalked this up to (perhaps overly heavy) pruning, trimming, and repot I had done. Here was it's position for most of the winter and spring. Picture taken in early May, just after repotting (in a pumice/lava/akadama mix, then buried in this pot)
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On Friday, I moved it from this position to one below the ~3 foot roof ledge. Today, I've noticed new growth budding... on just about every healthy piece of foliage!

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Was this stunting likely caused by the wind exposure, or is this normal considering the work I did to it this year?

If it's due to the wind, is it because of the soil being exposed, or because of the foliage being exposed? Should I remove the other tree I put in it's place, a much healthier, larger shinpaku with it's soil line beneath the ledge?
 
It's not uncommon for a tree to stall or sulk fir a time after a repot.

If you had cold or dry winds, it could cause some issues with new foliage but that is generally with deciduous trees, not juniper.
 
I see. I'm in Seattle, located a few blocks from a large lake. It's breezy on my roof quite often, but not too dry and definitely not cold. Would you say this is more likely related to the repot and pruning (in winter) than the wind?

I often hear about wind drying out soil, particularly on the top layer, but if anything, I've erred on the side of over watering, not under.
 
I see. I'm in Seattle, located a few blocks from a large lake. It's breezy on my roof quite often, but not too dry and definitely not cold. Would you say this is more likely related to the repot and pruning (in winter) than the wind?

I often hear about wind drying out soil, particularly on the top layer, but if anything, I've erred on the side of over watering, not under.

probably and if you have it in lava, akadama and pumice, as long as its draining well (and it should after a repot), its almost impossible to overwater.
Also is it normally that yellowish color?
 
Yes, the cultivar is a yellow one, known as Old Gold. It was my first tree, and I've since learned that many cultivars, particularly colored ones, are bad for bonsai.

This one is made considerably worse by my color blindness making it challenging to differentiate healthy and unhealthy growth. Long term plan is to graft some itoigawa cuttings I'm working on, but really this tree is just for me to learn on.
 
Further observation has led me to believe that the wind was indeed causing problems. Growth has exploded like the below pic all around the tree. Notice all the dead, ugly tips that I cut back which didn't heal over well, despite the trimming occurring in peak growth season around May.

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Going to have to look into a better solution to get my other juniper out of the wind. For now, it's going on the deck, but I like the display position. Some acrylic windscreens would look really nice behind it.
 
You understand trees in nature encounter wind all the time? As long as it wasn't cold weather, near freezing, I find it hard to believe the wind stunted growth.

I believe this was most likely sulking after you repotted it and it's now showing signs of getting over that.

Though I'm perplexed as to why you have the pot nested in a larger pot?
 
The purpose of the larger pot is to encourage faster trunk growth, similar to ground growing. It also looks nice, and I had the pot just lying around. Drainage/percolation does not seem to be an issue.
 
You understand trees in nature encounter wind all the time?
I'm not sure I follow this reasoning. The existence of a condition in nature does not imply that it is good for tree growth, much less in the bonsai environment. Trees in nature are very commonly stunted by high winds, as you see in any number of high altitude junipers.
 
Juniperus chinensis 'Old Gold' is likely a slower growing yellow cultivar than the normal green type, hence the stunteded growth particularly where its exposed to a stressful windy environment
 
I'm not sure I follow this reasoning. The existence of a condition in nature does not imply that it is good for tree growth, much less in the bonsai environment. Trees in nature are very commonly stunted by high winds, as you see in any number of high altitude junipers.
Unless you've been having winds in excess of 50 mph every day, I don't see this as the problem.

High altitude juniper are also stunted by heavy snow, short growing season, growing in a rock pocket with little nutrients available.
It's not just wind. It's a combination of all these things.

It is very common to have trees sulk after repot and take a few weeks to get going again.
 
The purpose of the larger pot is to encourage faster trunk growth, similar to ground growing. It also looks nice, and I had the pot just lying around. Drainage/percolation does not seem to be an issue.
Last two years when I started getting into junipers I made this assumption as well, and after reading a lot and from my own experience with different juniper root ball sizes relative to pot sizes, there is definitely diminishing returns as to how much faster a tree will grow if you give it more space(especially in the near term). You wont see the benefits of your larger container until those roots finish reaching out to the corners and really begin to pay you back for your investment in soil real estate.

Remember that a tree has a hormonal feedback loop
1)auxin (produced in buds/tips/runners, and gets sent to down the trunk to the roots to stimulate root growth. it also suppresses back budding)

2)cytokinin (produced in root tips, and gets sent up the trunk to produce buds and growth tips)

Junipers produce 'runners' or elongated tips, then those tips pump tons of auxin to expand the roots, then the roots send cytokinin to expand the foliage again, etc...that's why you shouldn't remove tips unless you are in refinement, or unless you are deliberately trying to influence ramification, control your tree's silhouette, or control taper/thickening in sections of your tree.

Last year, my junipers slowed to a halt around this time as well, and I was wondering if there was something wrong. Then in late August through October there was an explosion of growth that really surprised me.
 
Gosh, not sure the wind is an issue here. The extra heat gained by moving the tree down under the ledge though is advantageous… until gets too hot. Junipers are normally found in pretty arduous conditions and seem to keep ticking.

A couple thoughts. The big pot will require a larger amount of water and fertilizer to get the same effect as a smaller pot. It will also be harder to water and fertilize effectively. Finally a smaller pot will keep the roots warmer which in turn will push towards the edges of the container, accelerating growth.

Finally, wondering what is the main goal for this tree? Grow out or prune to a design?

Best,
DSD sends
 
Finally, wondering what is the main goal for this tree? Grow out or prune to a design?
Currently, the goal is to keep it alive. I think I worked it too heavily, so I'm going to give it a rest. I have some design ideas (need to fix the "slingshot" shape, want to graft on shinpaku cuttings), but currently that's not my focus.

Concerning the pot, you can see that it's planted in 2 gallon grow bag with bonsai substrate. The outer substrate is outdoor planter mix.
Finally a smaller pot will keep the roots warmer which in turn will push towards the edges of the container, accelerating growth.
I would think this would be the opposite. but maybe only in winter? I know some folks will bury their trees only in winter. My teacher encourages this as a way to encourage growth, either placing trees on soil beds or burying their containers. In fact, she has several planted in an old canoe!
 
Currently, the goal is to keep it alive. I think I worked it too heavily, so I'm going to give it a rest. I have some design ideas (need to fix the "slingshot" shape, want to graft on shinpaku cuttings), but currently that's not my focus.

Concerning the pot, you can see that it's planted in 2 gallon grow bag with bonsai substrate. The outer substrate is outdoor planter mix.
Good to know.

Using two medias with the dry one in the middle creates a lens effect. The outer media draws the water away from the inner one. As a result the tree gets underwatered. This stalls growth, even endangers the tree in extreme cases.

In the other case, if the medias are switched, (wetter inner/drier outer) usually the tree gets too much water and root rot follows.

If one wants to create a ‘larger pot’ the medias must be matched. Similar to slip potting. This may or may not accelerate the growth depending upon the amount of root mass in the central container. Once there is a critical root mass with roots populating the entire inner container, then there is every chance the tree growth will accelerate.
I would think this would be the opposite. but maybe only in winter? I know some folks will bury their trees only in winter. My teacher encourages this as a way to encourage growth, either placing trees on soil beds or burying their containers. In fact, she has several planted in an old canoe!

Winter storage is a whole different discipline. There is a BN developed resource posted here to help get one started.

Once again I’m hoping the medias are matched and the roots have critical mass..

cheers
DSD sends
 
Using two medias with the dry one in the middle creates a lens effect. The outer media draws the water away from the inner one. As a result the tree gets underwatered. This stalls growth, even endangers the tree in extreme cases.
This makes quite a lot of sense. Hard to say whether it's consistent with my experience, but I'll need to do some more tinkering. In your opinion, should I remove the root bag from this pot?

I'm not really considering winter storage, so much as making as good a winter environment as I can. This may include bottom heat for some of my deciduous species, especially as my roof gets quite cold and breezy.
Once there is a critical root mass with roots populating the entire inner container, then there is every chance the tree growth will accelerate.
I did repot this tree in the spring and pruned the roots heavily. Perhaps it's just been focusing on root growth?

Thanks so much for answering my silly questions.
 
This makes quite a lot of sense. Hard to say whether it's consistent with my experience, but I'll need to do some more tinkering. In your opinion, should I remove the root bag from this pot?
Absolutely. Personally not experienced in the effectiveness of root bags on roofing material. Someone here may be though. Usually put mesh pots, root bags etc on soil to get the ‘humidity effect’. Should be some though.

Some folks put the net pot or root bag inside a nursery pot for stability and humidity. I’ve done it to good effect with net pots.

I'm not really considering winter storage, so much as making as good a winter environment as I can. This may include bottom heat for some of my deciduous species, especially as my roof gets quite cold and breezy.
Time to start planning, imho.

I did repot this tree in the spring and pruned the roots heavily. Perhaps it's just been focusing on root growth?
Keeping the roots drier will stall their development.

Thanks so much for answering my silly questions.
You are most welcome. No honest questions here are silly.

Some day down the line I hope you will be helping others in need, paying it forward.

cheers
DSD sends
 
I just noticed you're based in Bothell. Do you do anything for winter treatment for your trees? We have mild winters, but I'd still like to keep things rolling to whatever extent I can. My teacher encourages bottom heat for root development, but would love to get some details on what other locals do.

I've had conflicts for like all of the PSBA events, but I have the workshop in September penciled in, with some specific work I'm saving for it. I wonder who I might see there from this forum.
 
Absolutely. Personally not experienced in the effectiveness of root bags on roofing material. Someone here may be though. Usually put mesh pots, root bags etc on soil to get the ‘humidity effect’. Should be some though.
Do you think that leaving the root bag in the pot but lowering the soil level of the outer soil would have a good effect? I would like to keep it growing on soil, and this large pot allows for that while still letting me position in full sun--the 16h sunny days these past weeks have been wonderful for my trees--which my planting beds don't make feasible.
 
Do you do anything for winter treatment for your trees?
I'm silly, I just saw the huge and wonderful over wintering resource you posted. That will be my homework for tonight, and I'll follow-up after reading it.
 
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