I have a number of trees that need larger pots but I’d like to also root prune them as some are larger and pot bound. What’s the thoughts on fall root pruning best time? all leaves need to be fallen off or sooner or completely dormant almost winter season? I believe @ROEBUK typically replant in the fall season is it just an up potting (slip pot) or full root prune? Thanks Lisa
Good morning Lisa, I do all mine in late Winter, around early March time. I have found that the roots get away better with warmer soil rather than struggling throughout the cold Winter months. D
Hi Lisa We do all of our root pruning in mid feb. when the pots are not frozen. The last few years we have decreased the pot size. Many of our large container grown trees are now in smaller pots. We have gone from 2' x 2' approx. size down to approx 18" x 18" . These are all 20 -40 year old trees. I take my rough edge pruning saw and literally cut back at least 6" - 8" all the way around and then the bottom as well. When trees are in their full dormancy it is virtually full proof to do dramatic root pruning with no ill effect. An example of a large tree to be root pruned was a 40 year old seiryu, went from 2' x 2' box down to a new 18" - 18" cedar box. The same tree with fall colors was from the mid 1990's when a garden magazine came out to do a photo shoot. Then it was in a 2' - 2' cedar box and 16 years old. We also had not yet painted our exterior of our home to the new color yet as well! I will make a video next feb when we do more re potting from big to smaller pots.
Thanks guys I really appreciate the input. I was really hoping to do them in like October but maybe not. I do have a couple trees I may need to just up pot cause they are like 1 gallon and not fairing well which makes me think they will die in the cold winter.
I asked this exact question of @ROEBUK a few months back and he does all of his after leaf drop and before any freezes, so late fall/early winter. He root prunes very aggressively and even pressure washes the root balls. If I have time later I will look for the post and link it. Now, I am not saying one method is better than the other, just that there appears to be more than one window in which this can be successful.
any time during dormancy is fine. Out here we do tend to get the odd freeze up combined with arctic outflow winds so the safer window is usually at the tail end of winter at our end. And yes pressure washing and then ship bare root which is what we have done in the past as well during the nursery days. Wrapped in moist newspaper then plastic bag. We even had trees shipped to us from Dick Van der Maat (holland) , bare rooted in winter, took over two weeks to arrive, all survived once potted.
Oh thanks guys for all this information I had planned to do a number of trees in late fall early winter so I’ll let you all know how it works out.
If the winter where you live is not too harsh, repotting after leaf fall can be done. Here, frosts don't usually come until late November, early December. When we repot in mid-October, the roots are safe. Most of the time. Repotting in late April is though being on the safe side if you don't have a cold greenhouse...
I just bought a very tall (5.5ft) Ikandi in a 3-gallon pot. I definitely want to up pot it to a 7-gallon or maybe 10-gallon grow bag but my fear is that the tree is fairly root bound and needs a semi-heavy root pruning. I should wait til late fall or possibly February next year before I try to up-pot this tree?
I like to up pot at around this time of year, that is after the first flush of leaves has fully expanded and the tree is about to start a period of root growth. Not everyone would agree, but for me it is the most logical time of year to do so.
@Connor Sullivan hi there, I am No expert but have a few maples. I have had a few that were severely pot bound from the nursery, my favourite I’ve named the rescue tree. My recommendation for the “safest”method would be to simply slip pot it and hope it takes the opportunity to benefits from that until it’s safer to root prune. (some of mine were so pot bound they did not root out into the new soil for quite some time. When I’ve done this I’ve hosed the root ball as much as I can and gently attempting to loosen soil and poke through a few inches the root ball a few times so water and new soil can find their way into it, I also used transplant treatment. Occasionally the root ball is so tight I cannot make any finger sized holes. As someone told me if your willing to lose the tree then you can root prune outside of the “safe zone” of when they are basically dormant as @Acerholic noted as his time to root prune. I have root pruned outside of the safe zone and fell into a heat wave the following day. My tree survived but looked horrible the remaining year and I had to keep it protected from harsh elements. 90% of it looks great today but I wonder if the remaining 10% is going to kill it off. It’s early in the season so definitely safer than summer but many will root prune when it works best for their schedule, you just may need to provided added protection and care. Hope this helps. Lisa
That's my recommendation also Lisa. I don't like to mess with the roots in Spring. But I'm very interested to hear M @maf thoughts, re his posting #12
When I have to slip-pot a tree, I fill in the space between the rootball and the new pot with a high proportion (70% +) of lava rock, and composted pine bark. It's easier to entangle the rootball when repotting it properly either in autumn, or preferrably in spring, just before budbreak.
No, just regular repotting. As in take tree out of old pot, remove some soil if needed, tease and trim roots, anything up to moderate root pruning. I wouldn't do full on surgery such as root pruning enough to go down to a smaller sized pot at this time of year but anything else is fair game. It makes sense for me to do this after stored energy has been moved from the roots to the canopy and energy is just beginning to be directed back down initiating root growth that will help the tree quickly establish in new pot. By my understanding of the phrase "slip potting" is a temporary measure and I have never done that.
I like to think of the tree's leaves as like solar panels, gathering energy, and the roots as like a battery, storing energy. It always makes more sense to change a battery when it is low (after a flush of top growth) rather than when it is full (before leaf out).
