Best time to repot satsuki azalea in Canada

I live in Southwestern Ontario, Canada and have around 10 years growing bonsai but no experience with azalea. Last year I bought a nice little satsuki azalea tree that requires repotting, but I don't know what is the safest time of the year to repot it. I heard that early spring, but I also heard after flowering in June. Please let me know which is the best time to repot it. Thanks.

I am no expert but what I have read is that it should be repotted after it flowers

Bonsai Tradition "requires" that azalea be potted after flowering. But if you don't care about flowers this early in its potted life, they PREFER to be repotted in early spring like any other plant, and likely will do better in the long run. Just to save energy, you probably could remove most of the flower buds when you repot.

Satsuki foliage buds start to swell in early spring, usually several months before the flower buds open. That is the ideal time to repot and perform root work.

Hi IBC members. Thanks very much for your replies. I kept the tree in an insulated garage beside a window and kept the temperature between 1oC and 8oC. It is still pretty cold and I still don't see any buds growing (please see photo below. I have a few additional questions:

The link provided says late March, but since there are no buds growing yet, I imagine I need to wait a few weeks?
The tree has a nice nebari and trunk, but some of the branches are long and spindly. Can I prune them hard now or do I need to leave the leaves at the end?

Thanks in advance for your help.

The problem with following a calendar to do your seasonal work is that different regions of the country (and world) have different climates and the same plant will grow at different times depending on where it is.  We have had a very cold winter here in N. GA and my satsukis started moving about two weeks ago.  Three winters ago, they were moving in early February and several were repotted in Mid February.  Last year, they were moving in Late February and were repotted in early March.  My point is that it's more important to listen to the tree and do work at the appropriate time which is when the tree is telling you to do it, as opposed to following a rigid schedule. Also, you can prune the branches back now, as well.

The problem with following a calendar to do your seasonal work is that different regions of the country (and world) have different climates and the same plant will grow at different times depending on where it is.

Very true, and Bonsai4me is a UK site. Much different from this side of the Atlantic. Lots of useful stuff on that site, but timetables don't translate for the USA.

OK, I will keep monitoring my tree and report when I see some buds starting to show. I will also do some hard prunning at that point. Thanks again for all your input.

ivillaCanada wrote:OK, I will keep monitoring my tree and report when I see some buds starting to show. I will also do some hard prunning at that point. Thanks again for all your input.

Just to give you some more concrete timelines, in S. Ontario with an azalea overwintered as you described, your azalea will probably start growing in mid-late April, then you can safely repot. Standard recommendation is to not let your azalea flower after you repot it.

Alternatively, you can let it flower, remove the flowers then repot. For us in S. Ontario with garage or cold frame wintered azaleas, that usually means mid-June repotting. My friend winters his in greenhouse conditions and his timelines are about one month earlier.

As for pruning... you can prune now or in the summer. Azaleas are flexible in pruning and repotting schedules.

Have fun - you have a sweet little tree there!

LSBonsai, thanks for the timelines for S.Ontario. What soil mix do you or your friend use when repotting azaleas in this area? Preferably not Japanese bonsai soil.

ivillaCanada wrote:LSBonsai, thanks for the timelines for S.Ontario. What soil mix do you or your friend use when repotting azaleas in this area? Preferably not Japanese bonsai soil.

As long as it is coarse and free draining the tree will be happy. We use kanuma because we have a few bags kicking around and we easily bend to peer pressure. However, last year I bought an azalea that has been growing in a terrible compacted mix of haydite and what looks like potting soil for many years. It is doing fine in it but requires careful watering. This year I will be barerooting it and putting it into kanuma. If I didn't have Japanese soils on hand, I would use pure lavarock and a fertilizer for acid loving trees. The guy I get lava from is actually in your neck of the woods near London. He can be contacted through www.bonsaiguy.ca

It can be repotted anytime it does not freeze.

In Mediterranean climates, don't repot in the dry hot summer. But in subtropical ones, like Japan, it can be repotted during summer.

ivillaCanada wrote:OK, I will keep monitoring my tree and report when I see some buds starting to show. I will also do some hard prunning at that point. Thanks again for all your input.

I know I'm on the other side of the country but if the tree were mine I would not root prune/re-pot and shoot prune in the same year.....been there, done that and it died even with the flowers removed. "Patience grass hopper"......
Cheers
Graham