JBP September Repotting?

Tidal Bonsai

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I found this throwback video series on JBP on YouTube. In part 1 they talk about repotting in March-April (pretty standard), but they also mention a window in mid-late Sept. has anyone reported JBP's this time of the year? If so, is this done so you can repot in the Fall and still decandle in the summer?

PS the time mentioned is around 9:30

 

Lynn E

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Hey B and B--Two blog/ posts on summer re-pot
Bjorn Bjorholm-- 07/2016 " Repot your bonsai in summer" and
Kaizen Bonsai--" Graham's Guide to Repotting Your Bonsai"
I would not re-pot and decandle. Cheers, Lynn
 
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Paradox

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Repotting JBP not recommended now unless emergency
 

0soyoung

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Mine, just like other pines, other conifers (juniper, thuja, tsuga, pseudotsuga, chamaecyparus, abies, picea), quince, azaleas/rhododendrons, elms, as well as other 'waxy' broad leafed species (like elms and oaks) don't have a problem with being repotted in August or September. I do it routinely.
 

Paradox

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Mine, just like other pines, other conifers (juniper, thuja, tsuga, pseudotsuga, chamaecyparus, abies, picea), quince, azaleas/rhododendrons, elms, as well as other 'waxy' broad leafed species (like elms and oaks) don't have a problem with being repotted in August or September. I do it routinely.


Your winter is typically much milder than what Brick NJ typically experiences.
 

0soyoung

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Your winter is typically much milder than what Brick NJ typically experiences.
There is a 50% probability of temperatures dropping to 32F by 18 October. Hard freeze (24F) doesn't occur until 24 November. I don't see any problem. Plenty of time to recover and for new roots to harden.

My winters are indeed milder. My 50% probability date is 15 November, about a month later. Hard freeze doesn't happen until mid-January.

A place like Steamboat Springs, CO would be an interesting place to experiment since the first frost date there is 30 Aug with hard freeze by 1 October. Certainly one could repot sometime in late July and (likely) into early August since temperate trees switch their growth pattern shortly after the summer solstice, but it is unclear how far one can push repotting (with root combing and pruning) into the period of deepening light frosts.
 

Leo in N E Illinois

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I routinely repot JBP in August and September. My very local micro-climate makes Summer-Autumn repotting more successful than Spring repotting. I am within a mile or so of Lake Michigan, my spring weather can be quite cool compared to those living just another 2 miles west of me. JBP does not ''wake up'' the way it would if you had warmer weather. I loose far fewer trees by repotting in late summer or early autumn than if I repot in spring. I just repotted a grafted JBP 'Kyokko Yatsubusa'' yesterday.

Trees I repot I do not decandle before repotting, nor do I decandle the following year. My growing season is too short to decandle more than once or twice in a 5 year period. I also provide winter protection in a well house that will stay at or above 32 F all winter. AND it stays below 40 F (4 C) all winter. Perfect, unfortunately not enough room for everything. But the JBP get ''priority seating''

The only JBP type I keep are the various cork bark JBP. These are ''touchy'', and are not as cold hardy as the typical JBP types. This likely plays into why Summer-Autumn repotting works better for me. I do not have any standard normal type JBP.
 

augustine

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I think those that do off season (not in spring) repotting successfully are very knowledgeable/experienced folk that really know the timing on the calendar as well as on the tree. Vance has it figured out after much experience, Leo too, and there are others. For instance I saw an article in Bonsai Today in which Mr. Kimura repotted JWP in August. However that was Mr. Kimura.

I think that it is safest to repot in spring (with the exception of summer repotting of Mugo per Vance Wood)
 

Wilson

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I am convinced that a few types of pine can handle summer/fall repots if they don't get left in frigid temps. I have never had trouble collecting Scots pine in August. I am also fairly sure the vigour of my kotobuki would handle a late season repot.
 

Tidal Bonsai

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Thanks for the answers, I am waiting till spring. I was just curious, because the way it was described seemed like such a common thing.
 

Paradox

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I repot my pines in spring when they tell me it's time, not by the calendar. When their buds start to swell, I know it's time.

I know by then, their roots have begun growing and that energy is starting to transfer to the buds.

Some years that is early March, others its late March.
 

GGB

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To me spring is when the buds get juicy and you can see the green pigment about to pop. ..hmm too sexual? That's when my year starts
 

PiñonJ

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Thanks for the answers, I am waiting till spring. I was just curious, because the way it was described seemed like such a common thing.
Trees have a spike in root growth in the fall, so it is a good time to repot in general. I can't tell you about JBP specifically.
 

BeebsBonsai

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I think it also depends on your ability to provide winter care. Do you have a place where you can keep the tree above freezing, but in the 30s? or is it going to be largely unprotected and have it's pot buried in the soil. It is definitely not ideal for most. Leo excluded, because Leo, going to Northwestern for those four years really made me realize how much different temps can be right on Chicago's northern lakeshore. I can totally see that spring could be a problem for repotting on the lake. What I would say is, if you can provide adequate shelter from freezing winds, and keep the tree in an area that is above freezing, then you might have success. But, at the same time, you have to think of the fact that, really you only have two more months before winter, and 6 or so until you could definitively repot at a better time. Why not just wait?

If you are talking about repotting a weak tree because you aren't getting water and air percolation or you think there is a root related issue, then you would definitely need really good winter protection. But, if it's life or death, rolling the dice might be the right call. If you can wait, wait.
 
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