Help with zanthoxylum piperitum

[Steinar]

Hello guys, my first ever post here.

I am new to bonsai, and one of the trees I bought is an 8 year old zanthoxylum piperitum. I bought it from a bonsai shop in Portugal, and brought it home to Norway. This is a large shop so I assumed trees were well cared for.

I've read a bit about the species, including that it might lose its leaves even if you move it from one room to another, so I thought that moving it to a different country was the reason why it started losing some of its leaves. Now a few weeks later, leaves are still dropping slowly, but it has also grown a considerable amount of new growth, from every major branch. I would estimate it's lost 10-15% of the original foliage. New shoots are still emerging and growing.

The tree is quite potbound (first picture), and also the roots are protruding up from the soil as you can see in the second picture. Maybe I shouldn't have bought this one, but I didn't know better. The last picture shows a mix of new and old growth.

The branches on the tree are too long, some go in the wrong direction, and I would like to trim quite a bit of it back. But I am thinking that of course the roots need help first, correct?

My question is - WHEN do I repot? It's now new year's, it's pushing out lots of new growth (I don't know if it knows what season it is, haha). I will happily do it now or wait, I just need someone experienced to tell me the best way forward.

 

[Bonsai Nut]

Welcome to the site!

There is a lot going on with this tree, particularly because you bought it in a warm country where it was still holding its foliage, and brought it to a colder country where it would typically be dormant at this time of year. Good news is that it is cold hardy to Zone 5, and most of Norway is much warmer. In the future you will want to keep this tree outdoors so that it can experience the seasons like any other deciduous tree. So the priority should be keeping the tree healthy until the spring, when you can hopefully move it outside and it can get attuned to natural cycles.

I do not have experience with this species, so I will give general advice and wait for others to chime in. Usually a deciduous tree will be dormant at this time of year, and you would plan to do repotting and root work in the early spring just as the tree is waking up, when the risk of a hard freeze is behind you, but the tree's buds are not yet opening. With a deciduous tree that did not go dormant, this is too late to try to move it outside and try to acclimate it to your area. Rather, just provide care as if it were a tropical, and do not do any major work on it until the spring.

Where do you live in Norway? (In general)? Would it be possible to get a photo of the entire tree?

 

[Steinar]

Hello Nut, and thanks for your quick response.

I live in Oslo, apparently right on the border between hardiness zones 7a and 7b.

Anyway, here are pictures of the tree. I have removed the leaves that were about to fall off (just by shuffling my fingers through).