Sun burn on new needles? - young larch (laricina)

[coh]

Well, the month of May was an outlier, in that we barely had any rain, most days were very sunny and drier than usual. My trees grow on my SE facing balcony, exposed to constant wind from the west side, so I think it might have been sort of the perfect storm for that repotted larch. It was pretty much dead by mid-June.

Trees in the neighbourhood are starting to really be thirsty, we've barely had any rain since June. That includes a few old larches growing nearby. We've had the same heatwave as you guys to start July off (7 consecutive days of 90+ F weather).

Same here. Bone dry for the last 2 months. The grass has gone brown and crunchy (bonus, no mowing ) and I have to water the perennial and shrub garden as they were suffering. So far the trees in the landscape are holding up pretty well. but if we don't get rain soon, they will start showing stress and dropping leaves.

 

[WNC Bonsai]

There seems to be a lot of varying information on these trees. Some sources say to repot before budbreak but most seem to recommend just when green tips show on the buds. Most say to use a free draining bonsai soil but a Scottish group says 60:40 grit and organic. Most say full sun, bit others say except in summer, and yet another says keep them under a tall tree in heat of summer. All say never let them dry out, always keep moist. I can see this is going to e a leaning experience for me next year!

 

[coh]

I've always heard they have a very narrow repotting window, essentially from when the buds start swelling (they start to look a tan color I believe) to when green just starts showing. However, as with most things...it depends. You can do it later as the needles start to show but that increases the risk significantly. Aftercare is the most important thing especially if you start pushing the envelope. For trees that haven't been repotted up here, I can usually get away with full sun all summer, except if we have a string of days in the 90s. Then I'll move them to an area that gets afternoon shade.

Since you're in an area that is somewhat out of their range, if I were you I'd try to find out how they handle them at the Arboretum down there...when do they repot and how much sun do they give them.