White Pine Help!

[Bogsi]

Hi all!
This is my first post, and have only been working with bonsai for the last year or so.

I purchased this little Japanese White Pine starter, and it seems to be struggling! And not sure how to help the wee thing.

The first photo is from March, at the nursery. The second photo is in May, autumn in NZ, when I repotted, being careful not to disturb the roots too much. And the latest in July, the middle of winter, currently, with browning tips!

Any clues as to how to help it? Or just keep on holding out hope that it will bounce back in spring.

Some more background, I'm based in Auckland, New Zealand and so it currently is the middle of winter, only dropping to 13 degrees celsius with lots of rain. The tree is in a sunny spot and only watered when the top couple cm were dry. Soil is a 30/70 pumice and organic mix.

 

[Shibui]

Howdy neighbour.
White pines have a reputation for being temperamental down here. I killed a few many years ago but have since grown some that have survived and grown well for about 10years so it is possible. Auckland won't be quite as hot in summer as here but also may not get quite enough cold in winter for white pine to stay healthy.
Your tree appears to look much better after the repot but the browning needles now is not a great sign.
Your cold is unlikely to be a problem for white pine which comes from cold mountains. Possible root problems possibly associated with too much water. One of the problems with repotting with minimal root disturbance is that the original roots are still in the original nursery mix. If new mix is quite different there can be problems with water moving from old to new and vice versa.
Would it be practical to keep it out of the rain for a few weeks but still have sun? If that's not practical, maybe try repotting properly. Now would be suitable in Auckland. Remove any compromised roots and make sure the roots are just in one soil mix rather than different types.
Sometimes just tilting the pot a bit can help more water drain out.

 

[Bogsi]

Kia Ora! Thanks so much for the advice!
And you are right about the weather, it has been one of our wettest winters in a while.
Will keep it in a more sheltered area, and hopefully it will dry out a tad. Will give repotting a go as well.