need help identifying disease and advice on cure.

[anthony burce]

Hi there I haven't posted in a while but I just recently purchased this older Japanese red pine. Compact Tanyosho ( Pinus Densiflora Umbraculifera- Compacta)
I traveled to Chester CA and found this. Originally priced at 99 but I pointed out the ailment and the nursery owner accepted $50. She mentioned maybe it was over watered. Today the weather in Chester is about 70 degrees. They had moved the plant underneath a full grown tree to give it a shade because it was obviously in stress. When I took it home and inspected the roots, I noticed very few white fleshy roots and a lot of black stinky rot. I removed a bit of the rot from the bottom of the root ball, and put the tree back in a larger pot. The substrate I used is sifted succulent and cactus formula. Very free draining. I sat the tree under a 50% shade and now I am here to beg for advice. My plan is to let it rest and give it time. Also, my instinct is to maybe slightly underwater it for awhile. Let me know if that is unsubstantiated or ill-advised.
Thank you.

 

[Potawatomi13]

Personally feel original diagnosis largely based on roots condition to be correct. Perhaps give somewhat more than 50% sun, be careful not to allow to dry out. Some will disagree but personally would mix up spray bottle of .75 to 100% recommended mixture of fertilizer to spray foliage every couple days. Reason is not much strength can come from roots just now.
Maybe irrelevent now but how much soil was removed from roots?

 

[anthony burce]

I removed the bottom 1/4 of the root mass. All of that was swampy and squishy. Is it possible for the die back to be a feature in later years?

 

[Dav4]

So, your current mix may be very free draining, but it could still be retaining too much moisture... and it's currently over potted in my opinion, which further worsens your moisture issue. Pines generally do best with full sun, but I'll defer to those who grow them closer to you. I do think you need to be very cautious with watering going forward until you can re-pot into a smaller container with better soil.

 

[Jzack605]

Sounds like it may have Phytophthora root rot. Treat with a potassium phosphate based fertilizer or fungicide as a drench. Reliant and agrifos fit the latter. I treat trees in the landscape at a rate of 12oz /100g as a fungi and up to 2qt /100g when it’s fertilizer.

 

[sorce]

If this was healthy with useable structure it wouldn't be worth $50.

We have to be careful about how discounts can make things seem like a good deal.

Sorce

 

[roberthu]

I would move it under full son and mist the foliage a few times a day. Mixing a diluted rate of fertilizer is a good idea. Watch out on your watering schedule. I’d water every other day given how big the pot is. If your soil retains more water, you can even water twice a week. I dug out a field grown JBP this spring and it is potted in a big pot with mostly organic soil. I only water every three days with full sun here in Georgia. Another JBP I dug out the same time is in mostly turface which is pretty free draining. But again it is in a bigger than ideal pot, so I water that one every other day.