Juniper root management

[ACrawl]

Here’s my blue point juniper. The nursery pot is 9 inches deep. In pics below, you can see some surface roots happened, and as I learned today, it had roots emerging from the drain holes.

My question please:

I’d imagine there’s a fair amount of roots in the pot. How would one manage moving this juniper to a more shallow pot? I don’t have the experience, but it seems like going from 9 inches deep to 3 or 4 inch would call for significant root pruning. The nursery pot it 9 inch diameter - I thought I’d move it into a 8 inch round pot when it’s time. The tree is currently 26 inch tall from the soil up (though I didn’t intend on keeping it that way).

Is it common practice to see that type of depth change when repotting the first time or is there some intermediate step I’m missing?

 

[Empty Mountain]

Reduce root mass gradually over multiple repottings. Nursery stock that hasn't been through any bonsai training shouldn't go straight into a pot that shallow, it should take a few years of applying bonsai techniques in training pots before it's ready for a bonsai pot. When you get the tree out of that nursery pot and take a look at the roots you'll probably find that you don't have enough fine roots close to the trunk, maybe most of the root system is at the end of long structural roots, there's no way to know until that first repotting. In that case you will have to slowly reduce the roots over the years to encourage more roots to grow close to the trunk to eventually build a root system that can exist in a shallow pot.

 

[Orion_metalhead]

You really dont know the extent of the roots until you go through a repot. Sometimes roots can accumulate at the bottom of a pot only, sometimes there is a layer at top and bottom, sometimes only in the middle...

Id probably repot next spring. Junipers can normally take a decent amount of root reduction since we find that their strength is in their foliage. In an initial repot such as from a nursery pot, its common to simply saw off the bottom 1/3rd of the roots, tease and spread out the rest neatly and move it into a flatter grow box of reasonable size, say 4" or 5" deep and let grow out for a few years, with progression work done when the specimen has recovered appropriately.

 

[Shibui]

I don't seem to have any problem reducing juniper roots by half and they'll often take even more reduction if given good conditions and care.
I think 1/3 root reduction is conservative but probably a good place to start given less experience.
Such a tree has the potential to be with you for many years so don't get caught up in needing to rush in and do everything immediately. Root reduction could be done in 2 or 3 steps over the next few years with some top styling interspersed whenever the tree appears strong enough.

 

[ACrawl]

I think 1/3 root reduction is conservative but probably a good place to start given less experience.
Such a tree has the potential to be with you for many years so don't get caught up in needing to rush in and do everything immediately. Root reduction could be done in 2 or 3 steps over the next few years with some top styling interspersed whenever the tree appears strong enough.

Thanks for the insight. I typically like to pick up practices that required time - in an effort to slow down and enjoy the process of things. Yet, the reminder not to rush is still needed and very much welcomed.

 

[ACrawl]

...slowly reduce the roots over the years to encourage more roots to grow close to the trunk to eventually build a root system that can exist in a shallow pot.

@Empty Mountain and @Orion_metalhead

This reminds me of something - the last time I attempted to repot a tree (many, many years ago), I remembered that most of the roots where at the bottom of a long trunk that was pretty much at the bottom of the pot. I didn't know what to do. Stuck it back in. It eventually died - compounding reasons I'm sure. Glad to have found a community here with people willing to share their knowledge.

 

[Orion_metalhead]

That sounds like what we woud call a tap root - depending on the species it can take several repots to remove or some others it be cleanly almost immediately.

Juniper with a long tap root, Id cut back in a way that ensure some finer feeder roots are left - once again, maintaining 50% - 70% of the fine feeder roots.

 

[Shibui]

This reminds me of something - the last time I attempted to repot a tree (many, many years ago), I remembered that most of the roots where at the bottom of a long trunk that was pretty much at the bottom of the pot. I didn't know what to do.

This is common with commercial stock. Low paid workers pot small trees from small pots into bigger pots. The easiest way is to dump the small root ball into the bottom of the bigger pot and dump soil in around it. This gives a long, buried trunk with all the roots in the bottom. Many species will produce new roots from the buried trunk but not all can do so. This is also why we get commercial stock with roots circling.

 

[ACrawl]

This gives a long, buried trunk with all the roots in the bottom. Many species will produce new roots from the buried trunk but not all can do so.

Yep. This sounds like what I remember - bark all the way down with 75% of the roots on the end.