I have found that you can safety repot containerized plants at any time. The important things are too use good quality planting soil, water the plants as needed, and keep them in a shady location after repotting. That said, I usually try to repot my JMs in the fall or early spring. I often repot in the fall so the maples will have more soil insulating their roots through the winter. In the spring, I tend to repot new plants that I've gotten. However, I've also repotting during the middle of summer and never had a problem from doing that.

Not yet. My goal is for next week. Mine are too large for their current container and it is a must that I do it now. I have prolonged it and I can see the effects of this mistake. The spring growth this year is definitely not what it was last year.

I'm certain that Dawgie is referring to "potting-up" in the summer, not "repotting", which includes some degree of removal of old soil and root work. "Repotting" any deciduous tree that is in leaf carrys the potential for disasterous results - even if the grower is very skilled.

Mine have been root-pruned & repotted for several weeks and are waking up and coming on nicely now.

Al

I potted up a 'Lima gold' and a 'Junihitoe' yesterday they were gift plants that had been grafted this winter. Both were ready for a larger pot.

Mum if your plants are all leafed out I would suggest you re-pot only if you are going to drop them into a larger pot with minimal fussing to the roots. If you root prune you will have issues.

There was some discussion a while back about autumn root pruning. I would definitely recommend this practice(Z7). My trees are having the best spring ever and I did not lose one plant out of 40 or so.

Here is a link that might be useful: UBC fall repotting

I got some 1st year grafts that were in 4 inch pots and moved them up to 1 gallon containers. I made my own mix of what I had available - peat, vermiculite, and some orchid mix (it had lots of chunky, well draining stuff). I filled the botton 1/4 of the pots with shredded pine bark and then filled the rest with my home-made brew. Then I topped off each pot with sheets of moss I gathered from the base of a tree in my woods. Hopefully that will transfer in some good forrest fungi and other helpful life forms. If there's something commercial that's supposed to be the bees knees, I'd like to know about it. I ordered 9 more grafts and will need to pot them up as well.

Thanks,

K4

I use Metromix for repotting. It's a commercial blend available at many nurseries in 3 cubic foot bags for about $14. Drains very well yet retains moisture. I've never lost a Japanese maple using this mix, repotting in just about every season.

"Repotting" any deciduous tree that is in leaf carrys the potential for disasterous results - even if the grower is very skilled."

At the every least, do not transplant when the plant is in a full flush of growth (wait till mid.-late summer), wait for it to set terminal buds. This will help reduce overall stress on the tree.
How many folks watch what the roots do on Acers once the plant/tree has finished a flush of growth above the soil/media line....not many is my guess (they explode into growth)??? A lot of decid. plants, but not all, work/grow in cycles...concentrate above, then concentrate below......

Schmoo

I have four (my first 4 last year) all mine grew at least 1/2 foot over the winter.. amazing... no repotting though... they are all leafing out and looking lovely.