Trying Japanese White Pine Tree Again? April 2025

Back in the Summer of 2021, I bought and planted a Japanese White Pine that included the name "Nana" on the tag - but otherwise the cultivar was not-listed. This small conifer tree was hanging out at the big box parking lot nursery for months and when it dropped in price, I grabbed it. By Summer 2022, the tree was gone. Browned out and dead . What caused the death? I'm not sure. Drought, likely. But, also...could it have been 'over watered'? Not sure, but who knows. What about hardiness? Are they hardy down to our Zone 6a/5b borderline? I'm not sure, either. Did I plant it incorrectly? Perhaps. These Home Depot trees are typically ball and burlap and are air-pruned/rooted - I think. They usually have a large, main trunk that terminates into a cut-end that has been rooted with some small root growth. In the past, I've cut these balls open - and when I did that - I've almost always LOST those trees. More recently, I've left t...