AusBonsai

Hi All,
I was advised when I bought the starter pots that this species was difficult to keep in Melbourne but decided to go ahead anyway. Well it seems we have gotten through the hottest part of the summer now and I now have decided to repot my cryptomeria japonicas into small bonsai pots. I trimmed around one third of the roots after untangling them and trimmed about the same of foliage. I think that the trunks are looking great and haven't done anything to them just yet. However, there has been some massive die back as you can see and I'm worried they won't survive.
I've fed them with a tiny bit of sulphate of potash and blood and bone. I've also sprayed a white oil just in case there was some microscopic bugs attacking it.
Do you have any suggestions to keep them going?

Gotta say they are not looking too good.

I'd lay off the fertiliser (blood and bone) and give them a bit of seasol and leave them in a semi sheltered spot.
By semi sheltered I mean of both full sunshine and in particular winds.

I'd consider soaking the tree and pot in a seasol bath to make sure the root ball is totally saturated.
Then I would let it naturally dry over a day or so before resuming a normal watering pattern.

By normal I mean that the pot should be "near too" dry (NOT DRY) before re-watering.

Good luck. Afraid to say that often by the time a tree starts looking good - it's gone.
This is not the case for you.

First things first, remember that your tree changes colour and dies back a little during Autumn/winter. It needs to be repotted in late August ( that is when i do mine) Prune off anything you know for sure is dead and water lightly over Winter and see if it bounces back. Temple cedars are tough so dont write it off just yet. If the branch is still flexible it should be okay only prune off the dried out ones.

Hi there,

I had one of these cryptos a while back and noticed mine went purple in parts after summer and in to autumn. After that it went brown and I too thought it was dead but kept it anyway and kept watering, only lightly this time. The tree went green again the following spring and was ripe in summer.

Given this experience I would say only cut off brown parts that are actually dry and treat the plant like all other pines and conifers and keep it on the slightly dry side. Seasol can't hurt so give it a try- only as directed though.

Cheers,

Brad Jackson.

I would try the product called Uplift, it is very good and can help ensure plants survive root pruning.

Thanks all very much for your help. It gives me some encouragement.
I have had another thought however, could it be the fungus-like organism, phytophthora? The information I have found says that it infects through the root system and leads to plant death. It thrives in wet soils above 12 deg C [54 deg F]. The disease kills the inner bark and reaches stems or branches. Visible symptoms include a dark layer of sapwood in areas around the upper root and crown and stressed leaves that can turn yellow-green or red-purple.
This information is from http://www.ehow.com/list_6526971_crypto ... eases.html
I hope it what I think it is. I'll take a look across the forum to see if anyone else has come across phytophthora.