I have an otherwise happy bald cypress that has some-but-not-all branches and leaves turning rust brown. See below for evidence of health and new growth and a picture of the rusty browning.
I don’t think it’s late enough in the season here in Louisiana for it to be taking on fall colors (lows of 72ish overnight, highs 90-100).
Rust mite? Water issues (I’d be surprised; I soak it twice a day, and it’s in a 10 gallon nursery pot with organic soil)?
I too am having one of my two go brown a little early. I was concerned until I noticed some of the neighborhood bald cypress doing it too. Our other club members feel like it could be a combination of heat and low water?
Nebraska was consistent 100+ for a week or two and 90+ for the past few weeks. Perhaps a fungus? My other one on the adjacent bench is a vibrant green like your top photo
Mine used to do that it is a water oxygen issue, in the heat of the summer if you are submerging it and it’s in heavy organics it’s having trouble breathing. I have lava, Pumic and some organic’s in the heat of the summer I’ll but the pot in an suacer with only an inch on water in the saucer so that the cypresses feet can get wet. Usually the inch will have evaporated within 8 hours
That makes sense. The tree is currently stuck in a nursery pot, in organic, sitting on the ground.
Could you advise on whether I should do an emergency repot into real bonsai substrate, whether it might improve by getting it on a proper bench, or whether I should leave it as-is and wait til spring to repot?
(I live in southern LA; it’s going to be hot for another two months.)
Yes, he is right that looks like sun burn. I do not have any bald cypress because I am up north but my spruces do the same thing. More shade or shade cloth will help. Ryan uses 30%, but I could imagine going up to 50% in LA. Not sure if misting works on bald cypress.
A repot will just lower its’ water uptake in the near future. Better off staying put till spring.
I would not do any root work, you may want to consider slip potting it. Tease out the sides and bottom slightly and slide it in an slightly larger container filling the gaps with a better substrate. If you want to wait it should be ok as well, bald cypress will grow in about any soil, but having the better water oxygen mix has made mine allot healthier
Thanks much for your reply! When @Erobling said it was a H2O/O2 balance issue, I assumed he meant the issue was O2, given twice daily soaking, given organic soil, and given it’s a BC.
Are you thinking it’s a lack-of-H2O penetration issue due to the tight soil?
I’d be surprised if it were sunburn; my entire yard is shaded, and the ~15 other shohin-sized-ish BCs in similar places don’t show any of the same symptoms.
Could be either o2 definitely an issue, however compacted soil and h20 uptake could hurt too. Just remember the plant drinks evaporated water, not liquid. So you need to keep in mind an environment to allow vapor
Yup! My guess was that it was an aeration issue, after listening to you all.
I just set up another couple benches in the yard, one of which has more shade, so I moved the BC to a shaded spot. The bench is basically mesh, so it should allow more aeration than sitting on the ground. Will update in a week or so!
Thank you all!