Repotting Question - Black Pine

(A. Gordon) #1


I have an 18-20 year old Yatsubusa Black Pine in an 8" pot that I’d like to repot this season (it’s been in its current pot for approx. two years).

Can you recommend a pot size to move up to as well as the proper soil mixture to purchase? The tree is approx. 13" tall now.

Lastly, the tree is in San Mateo, CA in the San Francisco Bay Area - when is an optimal time of year to begin repotting?


(Frank Corrigan) #2

If you are looking for an economical alternative for development purposes i would reccomend a terra cotta bulb pot. 10 inch round and 4 inch depth.
As for soil mix, my preference would be clay king or a combination of pumice, lava, granite and akadama. Paying attention to particle size and screening out all fines.
The tree looks like it may have lost a branch or two and a repot with an upsize to regain vigor is a great plan.
Nice tree!

(A. Gordon) #3

Hi Frank, thanks very much for the reply - I like the pot size and soil combination recommendations. Yes, the tree lost a branch last year =(. Any suggestions on when to repot? I’m very new to bonsai and have read that February is probably the latest to do so given the climate in the SF Bay Area. Thanks again!

(Jonas Dupuich) #4

Now is a good time to repot. It’s safe up until you see the buds start elongating, often in mid February depending on the year. At that point you can still repot but the more root work that’s done to the tree, the more stressful it is for the tree.

Am curious why you’re looking for a larger pot - I’d suggest a smaller pot and a focus on refining the branches at this stage.

(Ανδρέας Γάβρης) #5

Now is the right time to change the pot.
I would prefer an oval pot with a length of 25 cm.
This pine is very good material but I think you need to deal with shaping now.

(A. Gordon) #6

Thank you very much for the reply and for the recommendation to focus on shaping!

(A. Gordon) #7

Thanks, Jonas! Frankly, I don’t have an educated reason for wanting to repot to a larger container - just assumed in my naivety that repotting always meant bigger - so thank you for challenging that assumption. I’ll take your advice and repot to a smaller container and focus on refinement. That said, can you recommend a soil mixture to purchase from your site that is sufficient for an 8" or smaller pot?

(Jonas Dupuich) #8

A mix with about 30-40% akadama would be good for the tree. The other 70% can be a mix of pumice and/or lava (scoria). I currently have the akadama and pumice in stock.

(Stephen Fong) #9

I’m by no means an expert or even that experienced but I’ll offer this:

Generally, you only want to pot up into a larger size if you’re trying to achieve growth, since your tree is ready to start developing branches/refinement you would want to get it into a pot that is going to be similar to the final pot size or in future repottings you’re going to end up having to reduce the root mass to get it back into a smaller pot and stress the tree.

Also, do not bare root your pine when repotting it. Only gently tease out around 50% of the existing soil and replace with new soil. You can remove the remaining old soil in a future repotting several years later.