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Up-potting small Sango Kaku

2 months ago

I have some Sango Kaku JM’s I’ve grown up from seeds and had in pots for some time due to moving house. I will eventually plant some out in the yard starting the with the largest ones, because for me these aren’t best container JM’s, ( I’ve already missed best tree-planting time here, due to Life happening , so may only plant one out in the easiest to water area) but smaller ones I just want to upsize for better health & growth .

They are in “regular” potting soil of some sort, but now I’m able to do 5:1:1. Is it better to re- pot with least root disturbances, other than any girdling, or best to go to bareroot and spread out in the new mix so as to get benefits of new soil mix ? I suspect the latter, but just checking!

Trees have already started leafing out, but would I prune any large roots out or just do least trauma since actively growing now?

Comments (5)

  • 2 months ago

    Was trying to post in Maples but HOUZZ somehow gave only limited options.

  • 2 months ago


  • 2 months ago

    I did just find Al’s thread on potting up vs re- potting- very helpful maybe that’s most of the answer. Perhaps if any major encircling roots these would be untangled mainly to allow potting medium to fill in. But may not matter as much since those would not be major feeders.

    I think I am partly asking, if it does not do much good to pot up, is if not even worth the time, and I should just try to get the smaller pots to survive through this year until early next spring.

    I had thought that potting up would provide more growing medium for watering & make the small trees a bit more resilient during the hot summer, but that was when assumed the roots would automatically be “ happier “ when potted up.

  • 2 months ago

    Sorry I missed this discussion earlier and I'm not sure if I am really answering your question but I grow ALL my JM's in containers and when I buy a new one - almost always in leaf - I just pot up. No bare rooting, no root pruning. But I buy small, JM's here are most often grown in a very barky planting media anyway and I have yet to find one that had root issues serious enough to warrant bare rooting and correcting before planting up. And I do use a mix very similar to the 5-1-1, so again, very barky.

    But I have not grown any from seed intentionally so I can't address how that approach may be different or the impact that may have on the root system compared to store bought trees growing a very durable growers' mix :-)

    I should also tell you that seed grown Japanese maples can never be referred to by a cultivar name. Reproduction of all the attributes of a named cultivar, in this case Sango Kaku, can ONLY be achieved by asexual propagation - grafting or cuttings. Seed grown trees are just considered the straight species of Acer palmatum regardless of their source and may or may not resemble the parent tree very closely once they mature. So what you are growing may look like Sango Kaku but technically it is not. It could also grow up to look nothing like SK.

  • 2 months ago

    Thanks. gardengal, that is helpful. I will just pot up a few into 5:1:1 without messing with the roots really.

    I do realize these are not “ true” SK’s. I had potted up the seedlings with the best fall colors & have grown some in pots for over 5 years now, so a few are 3-4 feet tall, what I know is that they’re green in summer, yellow in fall & do have red stems of new growth and a generally vase shape, but don’t know what would happen in the ground over many years. So mainly I’d be cautious about how big they might get or about giving them a prime location where I need a predictable size or shape. I have some areas of yard that are like woods’ edge but I can still reach with hose for watering in so I’m thinking about just , plant, live or die.

    They came from trees I planted on another property 20 years ago, where I also had a lovely Viridis and container JM’s also, ( here I have a Full Moon, Crimson Queen , and Shishigashira in containers, but not in 5:1:1 yet), so there’s also that sentimental clinging to plants related to a former garden, and growing “ my babies”. And I have planted a number of things I managed to bring over.

    But also I am finding that after a couple of years in the new neighborhood, different soil & topography, I’m becoming more pragmatic about doing a new thing, not trying to re- create the old where it might not fit.