Is it OK to repot a shimpaku Juniper now?

[longd_au]

Hi

Just wondering if it is too early to re-pot a juniper now. One of my pot fell and shattered and I am thinking of re-potting it into a bonsai pot instead.
I noticed the buds on one of my elm is swelling and temperature in Melbourne seems to be warming up.

I will probably keep it in a green house over night and bring it out during the day until spring truly has arrived.

I am also just giving the roots a light trim with no top pruning.

Risk too high?

Regards,
Dennis

[shibui]

I've started to repot my trees and it is a lot colder up here than Melbourne. I usually leave the conifers until last but that's just because they don't seem to object to later root pruning rather than they don't survive earlier. I'd be quite happy to repot junipers now. When doing just a light root prune I think you could do it almost any time of year. Trees are far hardier than we give credit for.
In the greenhouse or out I would expect it to manage quite well at this time of year. Just keep a close eye on how dry things get as spring rolls in. I've seen trees suffer because I did not notice that the days were just a bit longer and drier, the temperature rising and the trees starting to grow and needing lots more water.

[longd_au]

Thanks Neil. I feel a lot more confident.
I might still take some extra precaution and place it in a green house at night.
I am going to switch it over to a new mix. 30% diatomaceous rocks, 30% scoria, 30% pine nuggets and 10% coir peat. All 2-3mm except for the pine nuggets.
I might leave the centre of the root ball untouched but bare root as much as I can.

[Daluke]

Hi,

I’ve bare rooted shimpaku with not one loss. I’ve repotted about 100 this way. These things are very tolerant and if it’s in a nursery pot I’d be encouraging you to remove everything soil wise in one hit. There is often old muck inside which will be holding your juniper back.

The easiest way to kill is to trim or pull ALL growing tips. But you said you won’t be doing that.

I’m not sure you need coir peat - it’s going to clog up your pot and retain too much moisture. You should let your trees dry out to help promote root growth and promote stronger self sufficient roots. Treeman wrote a post on this I believe?

Your mix seems pretty good otherwise.

You’ll find when you look at the roots that there are likely thicker blackish rotten ones (can be removed) and finer roots that are maroon x brown colour which should be kept.

Can you get your hands on pumice?

I’ve been using pumice (33%), scoria (33%) and orchiata pine bark (33%) and the conifers love it.

Also, smash it with seasol. Some think it’s pointless, but I swear by it. Foliage feed by spraying seasol onto the green and it will thrive.

Good luck!

[Pup]

Northern hemisphere do most of their repotting in February and March. When you look at their temperatures at this time.
They are around what ours are at the moment, I have done mine at this time without any problems.

[longd_au]

Awesome. Thanks for all your inputs.
Daluke: Thanks for your advice. I added peat to help slow the drying. I use automatic timers to water my plants as I don't have time balancing work and two children under 3.
I remember reading from a thread here that the national gallery in Canberra also adds coir peat to their mix. Or am I mistaken?
I tested the mix over the last few weeks in a pot without a plant and I noticed it dries quite quickly. I can imagine it will dry way too fast in summer.

I think this mix will still be dryer than the original soil the plant was in for the last few years. But I managed it by limiting the watering frequency. Will keep an eye on it this season as an experiment and modify as required.
I will only have two plants in this mix once I re-pot the Shimpaku. The other one is a chinese Elm which I've already re-potted in this mix.

[Daluke]

Elms get thirsty.

It seems the consensus, whatever the ingredients is 2 parts inorganic to 1 part organic for coniferous material and 2 parts organic to 1 part organic for deciduous.

Let me know how the growth goes on both because I’m interested in the topic of potting mediums and both species!

[melbrackstone]

Mixes, as always, can be contentious. I was told yesterday there's a US artist who travels extensively, and specialises in coniferous material, that if you use anything organic in your mix, he won't work with you.... Don't know how true it is...

[Ryceman3]

I have coir in my mix and I’m happy with it. I will say I haven’t put conifers in it yet though (elms & maples mainly, also some natives) but that will be changing when I repot a few in the next month or so. Like Dennis, I rely on auto watering a bit and I find the coir peat keeps in moisture without overly clogging my mix. Been using it for the last two years (about 10% of my mix) and I’m happy with the performance. As Dennis also said, it is part of the mix used in Canberra arboretum... can’t be all bad! But... as always, that’s just my experience with it, do what works for you!

[longd_au]

Just to add to the Coir peat discussion, for the Elm, I also added finely grated sphagnum and some green moss onto the surface. I remember Ryan Neil does this and I like the look of a layer of green moss on my pot though I am not sure how well it will survive in summer. I may further clot the mix so this is experiment number two.