0-10 year development questions

This question applies to all species I suppose, however I’m wondering about acer pal. So spring is the overall preferred season for repotting I know. What about teasing the soil, detangling the roots and increasing the growing can. Wouldn’t it make sense to do so now? This is just how I see it, but wouldn’t doing this now reduce the chances of disturbing growth in the spring?

If you can protect them from frost then maybe.
I always prefer doing any root work in spring, the chances of failure are a lot smaller.

I repot Acer palmatum in development in the spring. However, I have loosened the outer edges of root bound nursery stock and slip potted them in the fall. My goal in doing that is to start getting some fresh root growth so I have more to work with in the spring. I protect those trees, particularly the roots, from very cold temperatures.

Being you I would ask myself a question: ‘why now and not to wait till spring when it is much safer to do?’ what’s the hurry?

Well the only reason I would do it would be to avoid having to touch the roots in the spring. Thinking this would allow for growth in the spring to be uninterrupted. It seems counterproductive to , right as a young maple or pine is about to send out shoots and grow, to go in and fuss with the roots. Again not necessarily cutting any root, just splaying them out for even flare at the base and detangle.

You will damage and disturb the roots no matter how careful you are. Doing it now may cause the tree to not heal or compartmentalize any damage that is done.

There is logic in your thinking though, and not doing it as the tree is spending energy waking up makes sense, but doing it in spring gives the tree the longest time possible to survive the operation.


Yeah well we shall see. So the trees and seedlings I did this to, would they be better off heeled I in a group of about 25. Or bring them in to unheated garage. I’m just north of Boston. 6b. Until I joined Mirai a month ago, everything was going in unheated garage. Now with what I’ve learned, I’m second guessing putting anything in the unheated garage.

As far as I understand, metabolic rate drastically slows down during the fall time, thus the wounds created by teasing the roots would have a higher likelihood of dying back and not be compartmentalized, however, doing this work in the springtime would ensure higher metabolic activity and faster transportation of nutrients and compartmentalization that would leave a root system with a higher degree of success for recovery and response. Just as well, the foliar growth on deciduous in the spring time is largely determined by the root capacity to support such leaves, thus doing the work in fall or spring time wouldn’t delay any growth for spring.

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Okay that makes a lot of sense but how severely are roots really wounded. The wounds must not be visible without magnification right?

Depends on the species of course however from my experience bruising or crushing of root tissue can often cause dieback of roots, however, I suppose if you are aggressive enough you will notice torn roots

My experience is that there is always a fair bit of root damage when doing anything other than a slip pot without touching the root ball. Teasing out / untangling the roots always results in some scuff marks and tearing regardless of how careful you are. Cutting back the long roots is also a form of damage. Bending the roots to arrange them causes at least some internal damage (just as bending branches).

Since we are discussing repotting of a fair number of developmental trees in this thread, my guess is that that root work will be done fairly quickly which normally results in more damage. The good news is that younger trees will heal any root damage faster than older trees. At least I don’t want to spend an hour per tree when doing 25 developmental trees - I’ll spend that time on the older trees. For reference it takes me about 2 minutes to untangle, root prune, and repot a 4 year old Japanese maple seedling from a 4" (10 cm) pot to a flatter 6-8" (15-20 cm) pot. It is less than a minute for potting into the 4" pot.

Yeah I definitely take longer than that. I didn’t realize the damage is cased just by moving them. It makes sense because like you said with branches the damage can be internal. Maybe someone can answer this. How often when a tree is going from small to larger nursery cans do roots need to be teased and untangled? For the purpose of creating the best possible root base. I know all species will be different.

If the goal is to create the best root base it is probably necessary to work the roots each time the tree is repotted. If the work was done well in an early repotting it will often require minor work in later ones. Unlike the branches, you only get to work on the roots when you repot every few years.

For example, I have grown Japanese maples in the plastic drainage trays that are 6 - 12" (15 - 30 cm) diameter and 1.5 - 2" (4 - 6 cm) deep with holes in them. After a year or two I get a pad of roots in the bottom and circling roots. I cut those off when moving to the next larger pot every time. I root wash and sort out the inner root about every other repotting.

PS My previously listed repotting times were for the actual repotting. Pot prep generally takes that much time or even a bit more.

Okay that’s great thank you. It’s impossible to find the kind of information so I really appreciate it.

Technically when ever up-potting you’re going to want to work roots to continue to develop the nebari, just like when you prune the branches. However keep in mind that this process doesn’t need to be performed frequently, I’m a grower, and I do my field planted trees every 2 yrs, to develop nebari, if the tree is potted, in good soil maybe every 5 seasons, possibly longer.