Azalea's first potting.

Hi everyone,

I have an azalea that I want to put in a training pot (Duchess of Cypress). Right now it's in a nursery container.

My question is how much can I safely remove at one time? I've never worked with azalea so I'm a bit fuzzy on this one.

Thanks,
Ed

They have such a fibrous and dense root mass if they have been planted for any length of time, that you have to take it slowly. I generally remove the lower third with a saw and then tease out around the edges and jet spray carefully with a hose. Don't change to a completely different mix all in one go, as this can kill them. Put them into a training container that is only slightly larger than the remaining rootball. Too much space can lead to problems. When finished, top off with a layer of sphagnum or similar moss to hold humidity and remove all flower buds for this year. Make sure the tree can't move, so that the new fibrous roots aren't snapped off.

Thanks Kev.

The usual thing you do with azalea is to cut off the bottom part of the pot bound roots, as they will be black/unhealthy/rotten. I don't think you have to go as far as 1/3rd.

Then you have to pull open the root ball. You can make a cross cut with a knife in the bottom, and then pull open. Then it is recommended to soak the root ball for like 10-15 minutes.

If you want to remove a lot of roots for bonsai purposes, you would also have to remove foliage. The larger the leaf surface, the more moisture a plant loses and the more roots are needed. If you create too much of an imbalance, you will starve out the plant of moisture.

But you do have to fix the pot bound issue like described.

Glaucus wrote:The usual thing you do with azalea is to cut off the bottom part of the pot bound roots, as they will be black/unhealthy/rotten. I don't think you have to go as far as 1/3rd.

Then you have to pull open the root ball. You can make a cross cut with a knife in the bottom, and then pull open. Then it is recommended to soak the root ball for like 10-15 minutes.

If you want to remove a lot of roots for bonsai purposes, you would also have to remove foliage. The larger the leaf surface, the more moisture a plant loses and the more roots are needed. If you create too much of an imbalance, you will starve out the plant of moisture.

But you do have to fix the pot bound issue like described.

I'll be soon be repotting several Azalea for the first time too. I'm glad I read your post first!

My advice about cutting off the lower third is to get the rootball down from a nursery container, ready to eventually go into a bonsai pot. This is what I have always done. It may take two or three seasons to reduce the depth of the rootball sufficiently.

To add to this a bit. When it is impossible to pull open the root ball, which may be the case especially with florist azalea in my experience, it is recommended to cut out triangle pie pieces one by one over a few years until all of the old roots are gone. The florist azalea root balls I have seen had the peat and roots fused beyond any hope of untangling.

When you are putting it in a bonsai pot many people bare root and remove all the old soil. But this has some risk involved. People in certain climates speak strongly against this. It is a stress on the plant but if it survives then that is the best.

You don't need to pot with kanuma soil. We don't live in Kanuma city where this stuff is harvested next door. But still for an expensive imported bonsai that already is in kanuma, it is probably best. For local nursery stock, I use perlite with peat but in the future I want to see if I can add some pine bark if the pieces are the right size. Perlite is like kanuma but pH neutral. Peat makes the pH lower but can water log. Sadly all peat I have bought so far has been ground very finely. So it kind of water logs all by itself.

You just have to remember that besides bonsai logic, azalea and rhododendron already are paradoxical in that they love and need water, but at the same time they are very susceptible to fungi in the root balls. In nature they grow on a layer of humus on rocky mountain slopes. It is often overwatering that harms them rather than underwatering. Overwatering or water logging and too high pH is what kills azalea and rhododendron in people's gardens.

[edit]
Yeah, removing to fit in bonsai pot and removing bad roots are different things. I generally wouldn't move new nursery stock into a bonsai pot right away. I like to work for the long term.
You can cut off all foliage and cut off half the root ball and fit it in a bonsai pot.

Just to show how well they bud back:
https://www.youtube.com/watch?v=5oEB7OjlBl4&NR=1