Paging Dr. Mugo

[Kanorin]

Last week I got 2 free tickets to ride the mugo train due to the generosity of a local Bnut member who had to reduce some stock due to a move. Unfortunately, a couple of weeks before I got it, the larger of the two started to get brown needles - starting on the lowest branch, but starting to spread. I've looked all over the tree and can't find any evidence of scale or other obvious insects (but it's possible there could be borers or something in there)

What I know of the tree's history
Spring 2020: Repotted and wired by previous owner
Early July 2020: Needles began to brown on lowest branch
End of July: Came into my care
Over the past week: More needles started browning and this started spreading to other branches

Since the tree had been in a dark brown pot and started going south in July, I wondered if maybe the roots got cooked in the 3 consecutive weeks we had with highs in the 90-100 degrees F range. Since the tree was going downhill fast, I got a much larger vessel ready and decided to do a slip pot and get a look at the roots.

What I discovered in the roots
Most of the roots at the exterior of the rootball were black with the consistency of overdone spaghetti. Rotting.
While the surface and sides surrounding the tree were in a Boon's mix bonsai soil, there was still a lot of fine dirt in the rootball. Maybe it was ground grown until this spring - I'm not sure.




So I cut off a few of the exterior rotted roots (5-10% of rootmass), but I left the majority of the rootball as is and slip-potted into a large anderson flat.
Should I have taken a hose to the rootball to clean out more of the fine dirt?
Should I have cut off more of the rotten roots?
Was it probably too late to save it anyway?
Trying to learn so I know what to do next time something similar comes up.

 

[roberthu]

I would never wash a pine’s rootball. I think you did all the right things. Now you just need to let the pine fight this through.

 

[sorce]

Between the too quickly completed Shari, wiring, and potting, I'm surprised it waited this long to die.

That is a Shari that should have taken 10 years to do the Kathy Shaner way. Connecting patches over time.

Just the roots that die from the removal of a complete side of a tree is enough to clog such a small pot with ...overcooked spaghetti, killing what roots were left. That may be why the delay.

Sorce

 

[Kanorin]

Thanks for the replies. We'll see if it survives. If it does, I'll just let it recover next year. If it doesn't, it was still a free pot and a learning experience!

 

[Colorado]

I would not have wired and repotted this tree at the same time. That probably initiated the downward spiral. (I recognize you didn’t do that part).

 

[Waldo]

I tend to think you're on the right track with the overheated pot. those unglazed pots can get so hot you can hardly pick them up. I live in zone 5B, but we had pretty hot spell. high eighties and low 90s. I tested the pots with a laser thermometer they were 121 deg. F. on the sunny side. and that was at 10am. Probably got hotter by mid afternoon. by putting a sheet metal (aluminum) around the sunny side it reduced the temp of the pot to 90 deg. F. I think if you could drop something over the pot to protect it through the worst part of the heat and remove it otherwise it may help with cooking roots. Several years ago, I mistakenly set my bonsais on a steel I beam. Cooked the roots on all of them. So, I do think that those high a temps could be your problem. I have reduced the root mass by 50 to 60 % on my Mugos, trimmed branches, wired them, and repotted them at the , supposed, wrong time of the year, pretty much all at once .And none were affected by it. I don't believe I would want to try that with a JBP or a JWP. I would be careful about overheating or overwatering. But as Vance has indicated, Mugos are surprisingly tolerant and forgiving. Just sayin'. Hope your tree recovers .

 

[Kanorin]

I don't think this one is coming back...

 

[leatherback]

I don't think this one is coming back...

you might be onto something there