JBP repot - spring or summer

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Ok I know there’s multiple camps here but am looking for views with respect to my situation and weather .

Am from zone 4 where our spring can be completely unpredictable with cold below freezing temps . Am receiving a root bound , pot bound JBP in April and the owner told me that it needs a repot for sure as it hasn’t been repotted in many years . This is field grown JBP and has quite an amazing nibari and quite old a tree .

I have performed summer repot of my mugo pines that take summer repot like champs and no casualties ever . No worry of crazy cold temp after Julyupto September and temps are within 70-80 and amazing for root development .
I few if I do spring repot - I need to protect the tree from cold snaps , provide bottom heat and much more risky .

So am thinking I would do a summer repot during July upto august end after temps come down to 70s and treat it like my mugo rather than a spring repot.

Question to all you experienced JBP or pine guys - any reason why I should still consider spring repot and not summer repot ?

Regards,
Abhishek
 

bdmatt

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You shouldn't base your repottings on strict calendar dates. Instead, repot according to how your pine is responding to the weather. As Brian said, you should repot when the buds are starting to grow in the spring. If your area in the spring experiences freezing temps, then your pine would likely not push out growth because it still thinks its winter, ie since it's still cold, the pine will stay dormant. Timing for repottings always vary by region and can even vary by tree. So repot whenever your black pine is pushing out bud growth, whether that be in spring or early summer.
 

Paradox

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JBP are not the same as mugo pines
I repot JBP in spring

I've had mugos that survived summer repots too. I prefer spring repotting even for them though. In my experience, they recover better.
 
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Thank you for the reply .

So if you have a green house where you can maintain 35-40F and provide bottom heat , could you repot your pines in January or February and still have 2-3 months before spring arrives ?
 

Paradox

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Thank you for the reply .

So if you have a green house where you can maintain 35-40F and provide bottom heat , could you repot your pines in January or February and still have 2-3 months before spring arrives ?

where I am, JBP are typically swelling buds and ready to repot in mid to late March,
I dont have a greenhouse and I never provide bottom heat.
I will put them back in the cold frame or the garage for a night or two if we get a freeze after repotting
 

Potawatomi13

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Personally usually repot somewhat late to be after last freezing(no protecion available)when rain allows(no shelter for repotting) so can be even later into very early growth. Has not been a problem so far😜.
 

Shibui

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So if you have a green house where you can maintain 35-40F and provide bottom heat , could you repot your pines in January or February and still have 2-3 months before spring arrives ?
What is the point of all this manipulation of conditions so you can repot out of season? It is proven that spring, after frost, is safer for repotting so why the need to manipulate temps to change the timing?
I can repot pines from mid winter through to late spring here because of mild winters but I don't see any big difference in overall growth between early and later repot.
 

Leo in N E Illinois

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Zone 4 is awful cold for JBP, sure you can protect them over winter. The issue is the growing season is short, weeks or months shorter than the ideal growing season for JBP. JBP like a 200 day growing season, you need a long summer if you plan on de-candling and other techniques. In parts of Minnesota you are near or less than 100 day growing season. No time to grow, decandle, grow again and mature before freeze. JBP look like long needle Scott's pine when one is not able to decandle regularly. In zone 4 look at jack pines, scotts pines, mugo and other single flush pines. JBP are generally poor performers in short summer climates.

With changing climate, there's a possibility that marginal trees might begin to thrive, though this year, we had a hard freeze "on time" for an old fashioned winter, then poof, we warmed up to early autumn temps again. Rain for New Year's is not normal for me.
 
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Zone 4 is awful cold for JBP, sure you can protect them over winter. The issue is the growing season is short, weeks or months shorter than the ideal growing season for JBP. JBP like a 200 day growing season, you need a long summer if you plan on de-candling and other techniques. In parts of Minnesota you are near or less than 100 day growing season. No time to grow, decandle, grow again and mature before freeze. JBP look like long needle Scott's pine when one is not able to decandle regularly. In zone 4 look at jack pines, scotts pines, mugo and other single flush pines. JBP are generally poor performers in short summer climates.

With changing climate, there's a possibility that marginal trees might begin to thrive, though this year, we had a hard freeze "on time" for an old fashioned winter, then poof, we warmed up to early autumn temps again. Rain for New Year's is not normal for me.
JWP are excellent in zone 4, especially if you can find them grafted onto EWP instead of JBP.
Yeah I have stayed away from JBP precisely for this reason but the one I was offred was so cheap and amazing that I wanted to try. You are right ! May be just because the material is easily available , I want to jump on it . Need to curb my excitement and possibly pass over on it
 

Leo in N E Illinois

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I have repotted in spring, success was not 100%.
Due to work schedule I had more time to repot trees in summer and found August repotting in my "Lake Effect" micro-climatewas nearly as good as spring repotting. Key was waiting until night temps began dropping below 65F at night. Normally this begins in August. Still success was not 100%.

I am always wary about repotting, as this activity can prove fatal if you get careless, over prune or allow root tips to dry too much. Always provide some extra winter protection to trees repotted that year. Testing extremes of cold tolerance the winter after a repotting is a bad idea.
 
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