Coast redwood fungal issue

Hey Mirai fam! I purchased a coast redwood from Bob Shimon a few weeks ago at the Pacific Bonsai Expo and I’ve noticed a fungal problem starting to develop. It seems like all the new foliage is turning brown then gets fried. A few pieces of foliage that have hardened off have it as well. I want to get ahead of it because I purchased one from him in February in Oakland, it had the same issue and was dead by May. At the time I chalked it up to over watering (he keeps his redwoods in a river sand mix, it stays very wet) but I’ve been extra careful with the new one. I’ve only watered it once in the three weeks I’ve had it.

I reached out to Bob as well as some fellow American Bonsai Association of Sacramento members for some advice. Bob said try a fungicide and see how it goes. My fellow club member said they had (tree died) and are having a similar issue with a redwood but have not been able to rein it in. It appears to be a root issue. Her teacher Peter Tea recommended subdue maxx since it seems like a root issue. I applied some danconil, subdue maxx, and Cleary’s 336 granules today and am hoping the combo knocks out whatever it is.

Has anyone else had this issue? See below for pictures.
This is the one I currently have:

The one that died:
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Any advice would be a life saver! I really hope I didn’t end up paying over $600 for two stumps this year LOL

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I have bought a few trees from Bob, great trees but if you don’t live in his coastal climate, I have had trees turn just like yours. I have found that his soil medium needs to be changed out in the first spring in new climate. I have repotted with 2:1:1 and that solves it with, as Ryan would say, balance of water and oxygen. I don’t think you have a fungus, and if you do the underlying root health is the “root” of the problem.


Thanks Garrett!

You’re right, It’s definitely a root issue. From reading descriptions of diseases redwoods get, it looks like phytophthora. I asked Bob if I could get away with a repot now and keep it in an enclosed patio area, he recommended I wait until February.

I’m seeing it pop up on my other redwoods too. I didn’t keep them far enough apart. Two are planted in a 1:1:1 mixture and two are in straight akadama. 2 trees from both soil types are worse than the other in the same soil.

Looking at old pictures, one tree I’ve had since December 2020, had a similar issue when I got it. It was in a 1:1:1 soil, it’s now in akadama. I let that one get considerably more dry before watering and it seemed to bounced back in spring. But right now it’s one of the most fried looking ones!

At this point, my plan is to continue spraying every week/applying cleary’s, really watch the water, and hope for the best!

Have you checked for spider mites or other sucking insects? That could be what’s happening and could also explain the spread to other trees.

Hey Keith,

I have checked, thanks for the advice! I didn’t see any signs, there are a few other pests that are attracted to redwoods and I have yet to see any evidence of them as well.

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Have you tried using the hydrogen peroxide therapy when you do water to flush the soil with oxygen? My not solve your issue but could be a treatment to get you to a repot?
3Tbsp of 3% hydrogen peroxide to 1/2 gallon of water, water as normal.
Good luck, I’ve seen similar coloration on my red woods, likewise have no definitive cause. Mine are from liners, hoping they acclimate to my climate from seedling stage.

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Thanks Kyle!
I tried that with a previous redwood and I’m pretty sure it killed the tree. Not saying it doesn’t work, but I’m just hesitant! I know it’s worked great for a lot of people

I ended up repotting into a redwood box with a 1:1:1 mixture Monday the 12th. I have it in an enclosed patio that gets decent sun, in a cheap $30 “greenhouse” and on a heat pad. So far so good! The parts with the worst of the issue have died but the rest seems to be doing quite well, buds are even swelling a bit. I didn’t trim any live roots but was able to get rid of a good amount of dead ones.

I plan on keeping it where it is until my others start growing in spring, then move it outside. In another week or two I might treat with some Clearys 336 granules.

The substrate needs to be watered about every 3-5 days so I’m guessing the heat pad is allowing for some root growth.

Only time will tell. Wish me luck!

Hi Bob - I’m wondering if you could provide an update on your tree? I’m monitoring a new coast redwood acquisition of my own from Bob Shimon and wondering if I may have a similar issue.

Hey Chris!

It seems to be doing ok. 2 weeks after repotting I started my fungicide regiment. Cleary’s 336 granules, Danconil, and Subdie Maxx. I applied the Clearys every other week and sprayed Danconil and subdue maxx every week(both in separate spray bottles). It was looking pretty bad most of December and January, the buds that were on the tree previously turned brown and dried up. Once the “atmospheric river” we had here in CA ended and temps started to warm up I noticed lots of new fresh buds. I trimmed all the dried/infected looking areas off, sealed the wounds, and took the trimmings directly out into the yard waste bin far from my trees. Since then I turned the heat mat up to 77 degrees Fahrenheit and the buds are getting nice and fat, some are even starting to pop. Going to wait until my other redwoods are popping to put it outside.

I’m not saying it’s in the clear yet, a previous tree I got from him last year at the Mammoth Sale in Oakland leafed out then dried up and died. So we’ll see how spring goes.

I hear this is a pretty common issues with trees from Bob, unfortunately. I’ve heard Ryan Neil has even lost a few. But I was assured this fungicide regimen works well, and so far it seems legit. If you got it recently I highly suggest repotting into better soil.

Hope it pulls through!

Here are some pictures from early January before I trimmed all the nasty stuff off.

I too have a Coastal Redwood from Bob. I live down in Orange County and found my tree needed MUCH more water than I expected. Thirsty trees. This summer was it’t first SoCal summer and it suffered similarly to what your tips look like.

I repotted mine January this year and there was no root related issue that I saw. This to me looks like sun and wind burn. There was also a podcast that I was listening to and for the life of me I cannot remember which one it was, but it was one on the newer nutrition stuff Mirai is testing. There was a nutrient/mineral imbalance that can stunt the newest buds to where they just die off. I’m not sure what your water quality is like, but might be worth checking too. Just my 2cents.

Since moving my tree to slightly more protection from the Santa Ana winds (or off shore for that matter) and protecting it from hot southern sun, it has rebounded with TONS of new buds from all the scorched looking branches.

Thanks for the heads up!

I’ve spoken with quite a few people about it at my local club and online, all have had this issue with trees from Bob, unfortunately. Nao Tokutake bought one from him the same time as me and his is doing something similar. He’s had his in a greenhouse in Portland and hasn’t had to water it once since November! Soil is still water logged. He told me he even drilled several dozen holes in the side of the pot hoping it would help. Even in full sun here in sac the soil never even began to dry. I have many redwoods, and you’re right they are very thirsty, but I think this is a root problem, specifically Phytophthora(I didn’t get any cankers so I’m not 100%). When I repotted it in December I was able to get rid of a ton of dead and rotting roots.

I had some other redwoods get wind or frost damage this winter,(I moved last summer and my garden is now much more exposed to wind) but this one was already tucked away recuperating.

Thanks again for the 2cents! Definitely something I’ll keep an eye out for.

Ahh. Yeah, I drilled extra holes in the nursery pot when I got it. Thinking back too when I got it. I did take it out of the pot to clean the surface and find the base and front, so I could style it in the nursery pot until repotting time was right. When I put it back in the nursery pot I filled the extra space with straight pumice. I did that last May, so maybe that helped the roots some. I’m hoping to get another from Bob, now I’ll have to keep an eye for what you’re dealing with too. Thanks for sharing your experience!

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Thanks, for the update Bob. I hope yours pulls through.

This is my first Redwood and I’m still learning. I repotted mine this weekend into straight akadama and cut any browning off. Most of the roots seemed decently healthy - hopefully I wasn’t too conservative in root removal! What I’m hoping is that perhaps I was just overwatering it given Bob’s soil mix and/or I caught this all early enough since I got the tree from Bob just a few weeks ago.

Below is a picture from before the repot.

My wife and I plan to be at the Mammoth sale this weekend - I hope to not get into too much trouble with the auction, lol.

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Thanks! Buds are starting to push so we’ll see in a few months. Redwoods are pretty hardy, but I’d definitely recommend hitting it with the Danconil and Cleary’s 336 granules. Whatever this pathogen is it can easily kill redwoods. A fellow club member said he gets the same browning and die back but that combo seems to knock it out effectively. Redwoods are super fun, I especially like them because of the constant pinching. It keeps me busy and away from messing with my other trees too much.

That’s a nice tree, I actually almost bought that one at the bonsai expo in Oakland(at least I think it’s the same one)! I loved the almost circular deadwood feature. I chose a cheaper one because I wanted to get a pot from Nao Tokutake as well. Really hope it pulls through.

I can’t tempt myself with the Mammoth Sale this weekend unfortunately, have some house projects I need the money for. But, I do hope you’re able to grab some nice material!