Collecting oaks like Mauro Stemberger

Hy everyone

I watched this video from Mauro: Yamadori Bonsai Collection - YouTube

I’ve watched the video many times because i wanted to try his method of collecting oaks.
I’ve done everything like he describes but sadly he missed out to tell one important step.

The method in short: collect oaks in Dezember or Januar 》cover the tree with a black plastic bag so it gets no light and doesn’t loose to mutch water, then put it in a frost free greenhouse 》when the first leafes are out change the plastic bag from a black to a transparent one. Still let it in the greenhouse under a shade cloth. 》in the begining of june the tree can go outside but sill under shade.

The problem is that he never told when to remove the transparent bag from the tree. I tried to ask him in the comments but got no answer.

Has someone heard or practised this method before and can help me out with this?


1 Like

Ryan talks about the plastic bag method in this video


After taking it out of the greenhouse, knowing it still doesn’t have many new roots until after its first fall out of collection, I would leave the transparent bag on the tree for a little after moving it out of the green house. I also live in a very mediterranean climate, and by June, things can be getting dry.

For me, I would also open the bag in the mornings and maybe mist it. Then at the driest part of my days, I would close the bag back up to keep the foliage from drying out too much. Each week I would probably decrease the amount of time the bag is sealed as the tree is able to regulate its temperature and water requirements.


1 Like

Well he just briefly talks about it, unfortunately no answer to my question.

Thanks Danielle, that aproach sounds like it will work. I will try it that way. Hopefully it will work because i like this tree quite much.

1 Like

Where are you located and what type of oak is that?

It’s lovely. It might not need any bag at all. At least not black bag.

I live in lower austria and thats a quercus robur.
I just removed the black bag this weekend, it was collected in januar and stayed in the bag till now.


Depending on the roots that came out with the trees collection, I don’t think that would need a bag if you transition to sun slowly.

If there’s not many roots, a clear back would probably be a better transition