Suspected root rot on JWP

[BJJ&Bonsai]

We went from drought conditions to flash floods everyday for the last week and more rain in our forecast here in Durham. I’ve watched this JWP Iseli cultivar “Zig zag” slowly deteriorate since the beginning of the month. Roots looked healthy last time I pulled the tree, and I’ve added a thick layer of pumice to the bottom of the nursery container. I can only guess root rot? I’ve applied Neem, but no other fungicide. Thoughts?

 

[Shibui]

Unfortunately, just adding a layer of coarse material under the existing root ball rarely improves drainage. All it does is lift the soggy root ball up a bit.
Rain for a week, even torrential rain, is not enough to cause root rot. Root rot takes months to take hold.
Above ground symptoms of underwatering are almost identical to symptoms of root rot from overwatering because both cause dehydration.
Your mention of recent 'drought conditions', coupled with the paranoia about overwatering and mention of layers of pumice in the pot make me wonder if the tree has been too dry at some stage. The pumice will have disconnected the existing root ball from the pot making it so much easier for water to take the quick way around the root ball instead of through it. Slip potting can cause similar where the outer soil appears damp but the inner root ball is still way too dry. Symptoms can take a long time to show up in conifers so you may still be seeing problems from a few weeks ago.
I would encourage you to investigate how wet the internal root ball really is.
Apart from that I can't suggest much else to do apart from cross fingers and hope.

 

[rockm]

FWIW, Neem oil, heat and conifers are not a great combination. It can burn foliage. There is no reason to apply it if you suspect root issues. It's an insecticide that coats insects and smothers them basically. Applying oil-based sprays to a conifer in summer heat can cause stress.

 

[shohin_branches]

Can you share photos of the soil surface and the whole tree with the pot?

 

[Paradox]

Durham North Carolina???

Please put your location on your profile so we don't have to repeatedly ask you.

Looks like heat and too little water to me.
Root rot won't happen in just a week of high rain

 

[Deep Sea Diver]

Totally agree. Could be a lens effect.

With proper bonsai media one should be able to water the tree freely. A small drainage layer is all one needs. But the entire pot should be similar type media or issues can result.

Then, when it rains and one is concerned, simply chock up one side of the pot to lower the water table. Even will help somewhat with nursery soil. One can Drill holes in bottom at the “four corners” of the pot to get even better drainage.

Wondering also about the size of the pot. Can you please post a side image of the tree and pot?

Good Luck,
DSD sends

 

[BJJ&Bonsai]

FWIW, Neem oil, heat and conifers are not a great combination. It can burn foliage. There is no reason to apply it if you suspect root issues. It's an insecticide that coats insects and smothers them basically. Applying oil-based sprays to a conifer in summer heat can cause stress.

Duly noted, thanks Rock

 

[BJJ&Bonsai]

Durham North Carolina???

Please put your location on your profile so we don't have to repeatedly ask you.

Looks like heat and too little water to me.
Root rot won't happen in just a week of high rain

I had to google to see that there's a Durham Maine with a population of about 4000, but yes indeed the Durham of 300,000 in NC. Location added

 

[BJJ&Bonsai]

Totally agree. Could be a lens effect.

With proper bonsai media one should be able to water the tree freely. A small drainage layer is all one needs. But the entire pot should be similar type media or issues can result.

Then, when it rains and one is concerned, simply chock up one side of the pot to lower the water table. Even will help somewhat with nursery soil. One can Drill holes in bottom at the “four corners” of the pot to get even better drainage.

Wondering also about the size of the pot. Can you please post a side image of the tree and pot?

Good Luck,
DSD sends

I thought the notion of the "lens effect" has been dispelled by Michael Hagedorn, Julian Tsai, and others?
The tree was purchased early this summer, no opportunity to get it out of nursery soil and into bonsai media yet. Its been put on an angle and out of the rain in the greenhouse with the door and window open. I'll post further photos today.

 

[Deep Sea Diver]

Hmm… Not sure what you are referring to?

Is it the old trope about water drops on leaves?

The lens effect discussed essentially has to do with media in the shin or core being dissimilar to the media outside, such as a slip pot. So the core is a “lens’ or island with different water absorption qualities than the outer area.

Often it’s a shin of peat based nursery soil and a periphery of fast draining bonsai media. As a result one area is too wet and the other too dry.

In your case if the tree is merely in nursery media… recall nursery media is made to retain water and contains nutrients esp. carbon source so the trees grow faster. It has entirely different characteristics than bonsai media. However if peat based media dries completely through the core…. The media then becomes hydrophobic and can only be rehydrated by constant immersion overnight… or longer

Cheers
DSD sends

 

[BJJ&Bonsai]

Hmm… Not sure what you are referring to?

Is it the old trope about water drops on leaves?

The lens effect discussed essentially has to do with media in the shin or core being dissimilar to the media outside, such as a slip pot. So the core is a “lens’ or island with different water absorption qualities than the outer area.

Often it’s a shin of peat based nursery soil and a periphery of fast draining bonsai media. As a result one area is too wet and the other too dry.

In your case if the tree is merely in nursery media… recall nursery media is made to retain water and contains nutrients esp. carbon source so the trees grow faster. It has entirely different characteristics than bonsai media. However if peat based media dries completely through the core…. The media then becomes hydrophobic and can only be rehydrated by constant immersion overnight… or longer

Cheers
DSD sends

Ah, I see. Thanks for the clarification.

 

[Paradox]

I had to google to see that there's a Durham Maine with a population of about 4000, but yes indeed the Durham of 300,000 in NC. Location added

Still not seeing your location on your profile.
Did you add it to the right place?
Thanks