Japanese Juniper browning off?

[Shane Martin]

I have an advanced Japanese. Juniper around 25yrs old which was removed from the ground about a year ago. It's been left to recover without pruning and has been looking great until a couple of weeks ago when I noticed a few parts of this seasons new growth starting to slowly wilt and brown off. The rest of the tree is covered in new growth and buds. We have had a ton of rain over the past few weeks and I was thinking it might be a soil/drainage problem?
I'm pretty sure the soil is what it came out of the ground with, so I'm guessing with the rainfall of late the soil may be waterlogged maybe and not draining too well. Can I remove ALL the old soil NOW ? (in Northern NSW),and replace it with a better free draining bonsai mix/diatomite combo 50/50.
I've never completely barerooted a juniper before, so any advice on this would be appreciated. I'm not ready to style the tree just yet so it would just be a switch of soil mix at this time.

[bodhidharma]

It is my experience that Juni's brown off on occasion and i wouldnt be to concerned. The latest i have repotted a Juni is January and the tree is fine. I do not think it a good idea to repot and work the roots at this time of year but if you are concerned you can pot it up to a larger pot. My rule of thumb when working a Juni is to never take off more than 1/3 of the rootball to be safe.

[Shane Martin]

Hi Bodhi,
I've since had advice telling me that it is the result of wet foliage that's been scalded by the heat of the sun..... caused in affect by our crazy wet and hot summer here in northern NSW. One minute pouring rain.... next minute blue sky and scorching hot sun. I have since removed all the affected foliage, and given it a bit of protection, and the problem has ceased. I've also cleaned out and thinned the foliage to get some better air flow around the tree, and it looks so much the better for it. I'll wait 'til next spring to repot, and in the meantime, working on some jins and an overall plan for its styling. I'm in total agreement with you on the amount of rootball to remove, being 1/3 max with juni procumbens.... any more and I've always had major set backs which took forever to recover, if at all.

[Mojo Moyogi]

Hi Bodhi,
I've since had advice telling me that it is the result of wet foliage that's been scalded by the heat of the sun..... caused in affect by our crazy wet and hot summer here in northern NSW. One minute pouring rain.... next minute blue sky and scorching hot sun.

Hi Shane, there is very little chance that what is affecting your J.pro.Nana is sun scorch, Japanese Junipers in fact like foliar moisture and warm to hot summers/high rainfall/overcast with sunny periods sounds like the prefered climate for the tree, not unlike it's indigenous climate.

The second picture that you have posted of a stunted, desicated, pale green to tan/grey shoot looks like foliage that has been deprived sunlight, this is very common in procumbens. If you were to periodically thin foliage throughout the canopy of your tree to relieve some of the congestion, this would be far less likely to occur.

The other images of poor foliage does look a little like the result of wet feet, clearly there are noticeable differences between healthy and weaker branches, improved airflow through the canopy may help a little bit also.

If you do suspect that the tree is still in a high proportion of field soil, rather than risk removing the soil at this time of year, I would be inclined to slip pot the tree into a styro box of 20mm gravel which would give the tree some airflow at the extremities of the root ball until a more suitable time of the year for repotting. Elevating the tree and allowing air circulation around the container is a must, mesh benches are great for this purpose.

If this tree has been dug only a little over a year ago, the emergent roots themselves are quite immature and the tree is still in what I would describe as a recovery period. In fact, I would be reluctant to do anything other than thinning on a field grown conifer for a full 2 years after being dug regardless of how the tree is performing above ground and I would be just as reluctant to sell such a tree, and never in a high proportion of field soil. Even vigourous deciduous species, I would allow 12 months to establish in the pot.

Good luck and keep us posted.

Cheers,
Mojo