Dawn Redwood - Leaves turning brown

[IsaM]

I repotted my dawn redwood forest in early spring (before buds swelled). It was left out of the sun for 3 weeks post repot and it seemed to be fine, has put out a load of growth. I'm in London UK where temperatures have been c.10c for the last few weeks but has warmed up in the last couple of weeks to more like 15c.

My understanding is redwoods prefer to be damp vs. dry so it's potted in Kaizen Bonsai's high water retention mix: https://www.kaizenbonsai.com/premium-bonsai-compost-no1-high-moisture-retention-

The growth has started developing brown patches. Not necessarily at the tips, often in the middle of branches/leaves. The pictures aren't great but this is consistent across every tree (11 in the forest) and has gotten worse since I last took these photos.

The trees get full sun from 9am-4pm. It also does get a bit windy in my garden unfortunately. Any idea what might be causing it? Anyone else had this issue?

Any thoughts welcome!

 

[LittleDingus]

It looks kinda like this?



Mine do that in the spring sometimes if it's still cool. We dipped below freezing for a couple nights earlier this week. It's routinely been 10C at night here...maybe a bit cooler even...since this first flush budded out.

Sometimes the young leaves are more purple than brown even. The cold slows the growth...or can even kill...the chlorophyll structures so you see the other pigments. Same reason maple leaves emerge redish/purplish, etc...Also the same reason leaves color in the winter except in spring it's because the chlorophyll hasn't filled in yet.

If it is the same thing (hard to tell color sometimes), it's nothing to worry about. New growth should be bright green and healthy and will stay that way once the temps climb a bit higher

 

[IsaM]

Thanks very much for the reply. Looks exactly like your images. Have found a couple of older threads on the same topic with similar suggestions. We have had some very cold nights, hopefully gets its colour back soon! Thanks again.