Bonsai Study Group Forum

Species Specific => Japanese Black Pine Bonsai Discussion => Topic started by: mickbonsai on December 13, 2015, 10:18 AM

Title: japanese black pine (kotobuki)
Post by: mickbonsai on December 13, 2015, 10:18 AM
I was wondering if anybody ever grew or is growing Japanese black pine (Kotobuki) in Colorado or in zone 5b?
Title: Re: japanese black pine (kotobuki)
Post by: Leo in NE Illinois on March 03, 2016, 12:39 PM
I've got a Kotobuki, a second year graft, getting ready for its 3rd growing season. In the Chicago-Milwaukee area, JBP in general is only marginally hardy, even in the ground. Some years it makes it, some years it they freeze out. I always protect my JBP from extreme cold in my area, too many dead trees on the compost pile to risk our zone 5 weather. If you plant a JBP out in zone 5, it may last a while, but eventually one winter or another will do it in. In a pot, it is even more cold sensitive. I currently protect mine in pots from temperatures below 23 F.

Second - grafted trees, regardless of how "good" a graft looks, it takes a long time for a graft to fuse completely with the understock. Water or sap in the unhealed part of the graft can freeze, expand and separate the graft union. For the first 5 years after grafting, it is probably best to protect trees from freezing much below 31 or 30 F. Light frost does not seem to be a problem. Some will say no problem after 3 growing seasons, some will say it takes longer. The quality of the graft union makes a difference. Some "nursery production grade" grafts can be 10 years before being fully fused.

So in all cases, in zone 5b, grafted or on own roots, I would protect 'Kotobuki' from severe cold. And if a grafted tree, I would protect the tree from hard freezes until it is maybe 5 years old.
Title: Re: japanese black pine (kotobuki)
Post by: mickbonsai on March 03, 2016, 07:09 PM
Thanks for the input I'm growing 2 kotobuki and 3 regular JBP right now I've never grown them in Colorado so its more of a challenge for me to see how they do, I keep them in the garage during the winter completely in the dark with no ill effects so far I hope they come out of dormancy O.k.   
Title: Re: japanese black pine (kotobuki)
Post by: Leo in NE Illinois on August 23, 2016, 02:38 PM
Garage should e enough added protection