I have 4 mature palmatum cultivars all have roughly 75-85mm diameter thick trunks at the base, 2.5 -3mhigh, Shigitatsu Sawa, osakazuki, katsura and a peaches and cream 1m high 2m+ wide..all have been in 120-130ltr pots for 3/4 years and the root bed is solid across the 70cm top. How much would you prune off this before reporting into 160ltr pots?
This is a good thread for this time of year R. Everyone has their own idea about how much to remove, but for me it's always been around the 30%. I know some that go to 50 %, but I've never been that brave tbh. As you are upping the pot size I would go for the 30%. Others may have a different opinion, but that's my thoughts. Hope thats of some help R.
Thanks D.. 30% sounds about right for me..I was thinking of using an electric carving knife..as it’s a solid bed of fine roots
@Acerholic 's advice sounds good. I would remove mostly the bottom with a saw (at least 1/3). Then cut slightly a small part all around the exterior and then use a chopstick or something similar but heavier to guide the roots radialy and verticaly so they can grow freely.
A couple of cultivars from 2018 both lifted on the 03/12/18 root pruned and re potted into 20ltr for the going green but this was then slipped potted into a 45 ltr pot in December 2020 for this season and won't be touched now for at least two years dependent on the root growth from now on wards ? The pictures show the tree the following year 2019 through the summer then fall, note the yellow leaf colour which is wrong for this cultivar , then again 2020 summer then the fall colour which it should be a stunning orange with reds. The second cultivar Mizui kiguri again lifted and root pruned same day but in to a 60 ltr container same process and then early spring 2020 then the fall. The removal of roots is basically the same dependent on what size container it goes in, just make sure you have a good spacing between the edge of the pot to the edge of the root ball so it has space to re grow the new roots, see last picture of another one i did recently 45 into a 60ltr and the space allowed.
Few more over the last four years.... The last group of pics Ki hachijo was from 2020 ear marked for lifting early in the year so bottom part was taken off during the summer then lifted in the fall , huge root ball on this so i had to pressure wash all the crude etc off this one then trim back for it's new 80 ltr pot looking at this today and it's budding up very nicely , colours on this will be stunning, very last pic is another Ki hach which can be seen in picture 6 when that was root pruned then beautiful fall colours which followed.
@ROEBUK most helpful thanks ever so much...very helpful photos. Woww some of that pruning is vigorous. Do you root prune some of the planted trees? Looks like you hose off a lot of the soil before repotting.. So root pruning does not necessarily knock them back for a year or two.. Do you use Mycorrhizal fungus? My shigitatsu sawa needed doing last year..did not get so much vigorous new growth as normal. Can I ask what soil/media mix you use?
If that's a baby R, your adult trees must be enormous Lol. Quite a challenge you have set yourself for 2021.
I’ve had that one for 20 years..it’s a crimson queen..purchased as a 30cm tree..embarrassingly I had it in a medium sized pot along with green viridis, there was a kind of ying, yang thing going on but the viridis suddenly died one year..quite early on..so not so ying yang at all!!!
Those two do look so good opposite each other. I love playing around with contrasts, something you can only really do when in pots. A bit more difficult when planted in the ground. But looking at M @ROEBUK photos he manages it very well indeed.
Agree with you D, it is fun to play with contrasts and even more when you find 2 maples that compliment each other. So far I experimented that orangeola and viridis in full sun works very well all the season. Another one I enjoyed was a tall Inaba shidare with a small Deshojo at her feet, at least the contrast was lovely in the end of spring, when Deshojo was fading slowly into pale red before ending switching to green for the summer. This last pic is just a random improvised mix of maples but works well too Another nice addition to a solitary Shishigashira is to plant around him some purple campanula muralis (campanula portenschlagiana ) If you know more great combination, feel free to share them (sorry for off topic)...
Wouldn't class the pruning to severe for me or my trees , i like to go to a point where i know the tree will survive but may take two or three years to come back dependent on how much i remove , some times i will just do a light root "tease" where i just give a good pull out of the roots then trim them back but leaving about 2 to 3 inches still protruding from the root ball, similar to a good "slip"potting , this method i usually find they will come back the year after again dependent on the cultivar. I do many ground grown trees i tend to find these cope better with a good cutting back of their roots because they have had time to set out a good symmetrical spreading of the root system over the years as you can see from the Going green and Mizui kiguri pictures there is plenty of room in the root ball mass for you to get into without damaging the main feeder roots, more visual and i find easier to work on. I find the cultivars which have been brought on in pots over the years and been left to girdle the pots far more challenging to work with. Some of the root balls can be a night mare to work with especially if they are old and thick set (dense) you can pick as much as you want with your mini rakes brushes and picks but i have learnt from experience to just pressure wash them , you will be amazed at all the old growing medium that comes out ,then you can start again with new mediums compost bark chippings etc and the cultivar will repay you in the years after, it's a new lease of life for them. My growing medium is the same as what it was when i first started with maples well over two decades now , and that is irish moss peat @ 50% pine bark nuggets @ 40% and j innes no3 @ 10% have just changed my j innes 3 to Bord na mona which is not claggy as some of the other brands in the UK. I know every one as their own takes and ratios when it comes to growing mediums but i find this works very well for me and my trees. Quite a lot of people in the UK now use the Melcourt range of composted pine bark , peat free composts etc and seem to be having good results. Yes i do use Mycorrhizal fungus i find the granular range is better over the powder though. Added a few more pictures of dissectums which were done recently. Branch and root pruned and doing nicely. First set of pics a Baldsmith 10 years in the ground lower half of tree branch pruned in 2018 and lifted in the fall of 2020 well over seven foot in height. Second set of pics Watnong again lower half removed in 2018 then lifted in the fall 2019 and then pictures from spring and then fall 2020, so as you can see Maples are very forgiving when it comes to pruning and lifting. Then to finish if you really want to be harsh with your trees the saw method very quick to do with hard packed roots, this was last done three years ago then another three before and it just keeps on bouncing back , and to finish some pics of my growing medium as well and the new j innes no 3.
@ROEBUK thanks for your effort explaining your method and going into this level of detail, very interesting and helpful. They certainly look healthy!
Good morning M, really interested in your new John innes no3. How long have you been using it? Have you noticed a big difference? Your mix is identical to mine , but I'm always willing to improve if you think the Bordna mona is better. I use Levington BTW.
Great post from a master of this subject! :) I think Melcourt is the benchmark, unfortunately these products are not exported at all, so the rest of us must do without. But have been very impressed with the composted pine bark, and also some custom mixes they make for various UK nurseries. I agree the granular form of mycorrhizae seems better, not the least because it doesn't blow away (or up your nose) in the slightest breeze. Have used Rootgrow for years, but that's another British product so don't know what the availability will be post-Brexit. Rootgrow also seems to have more species than our German or French producers, at least those I've found, and is specialized endo (inside the root-wall, which is what is needed for Acer) whereas the other products are general purpose, containing about equal parts of endo- and (wasted) ecto-mycorrhizae. Although I do have some oaks to plant and repot, so... Here's my question: Brits are always talking about John Innes no 3 (or some other number). But what is it exactly? A brand, or a mix? Have always wondered and never got around to asking.
Even over here it is very expensive, so if it were exported to Europe it would be astronomical prices. Going the same way as Akadama price wise.
It's a mix, very gritty and supplemented with loam, peat substitute, sand and fertiliser. I use no3 for large or older trees as it has more feed and no2 for small grafts etc as it has less fertiliser added. Many brands produce it but IMO, some better than others. And as M @ROEBUK has pointed out, a new producer which is less clump forming. Am going to give it a try next season btw.
Thanks! So, each brand is different? Was there a brand originally do you know, and who is or was John Innes? What are the other types. Don't want to pester :)P but have truly always wondered about it, heh.
I think as a whole the ingredients are much the same, but after trying a few brands as M has; I decided upon Westland. I think tbh we all over think our mixtures, but a bit like everything we all come to different conclusions after trial and error. The ingredients 'should' be the same whoever sells it, otherwise it is not John Innes. It came to light in 1938-39 in the retail trade as John Innes compost. Two scientists developed it in the 1930's, William Lawrence and John Newell who were based at the John Innes Horticultural Institution. Regarding John Innes, I have copied this for you. I think it explains him better than I can write it. John Innes (philanthropist) Hope that gives you an idea what we Brits are always going on about when referring to John Innes compost.
Added some pics of the Bord na mona j innes no 3 i use now , as you can see from the first pic i measured out 500 ml of the mix then added 5oo ml of water and left to stand for a hour then strained , you can see i have managed to strain just over 400 ml of the water back out of the mixture which is a good sign which in turn has left a well opened mixture and not a muddy claggy mix that i tend to have found with other makes. Have left the mass to drain over night in my workshop and will post some more pics tomorrow. Again it's trial and error with finding something your trees like to grow in without having constant wet feet. D couldn't have put the description better myself , basically a generic term for the compost but each company producing said compost using the "formula" or as near has possible to it. I definitely find this brand more lighter and free draining when mixed with my other components.
That is very important info, I will definatly give it a try when my stock of Westland has run out. This is yet another good reason why people should get involved with the forum. So much good advice. Thanks M.
Some more pics of various cultivars given the " Yorkshire pruning method " :):) over the past five years, first set a large ground grown viridis lifted in 2015 then how it managed over the next three years and finally when i decided to cloud prune the tree for something different to look at and how it's coping now given the large amount of branches removed to achieve it's new look, this was an excellent size and shape to do this on and will look very good this year loads of new growth and bud swelling up nicely. Second set of a large old Garnet again ground grown then into a container then finally given a "bonsai style" appearance As you can see i am just basically playing with these cultivars trying different ways of making them look more interesting for me ? then a couple of pics of murasaki kiyohime which was again ground growing but i decided to lift this in June 2017 after removing the lower section of the tree then just using hedge clippers removing a substantial amount off the top of the crown trimming the roots and re potting , next pic same tree in May 2018. One of the main reasons for cloud pruning the viridis was it took up so much room on the drive and it was a night mare to get into do general maintenance on , now it's so much easier made a small gap at the back but i could still do with finding a new spot for it to live, then i can put at least another three large pots there. The last set is of a large Kashima again heavily lower limb pruned and same treatment on the roots , same tree a year after in it's new 80 ltr pot. So as you can see any tree can be dug up root & branch pruned then re potted either in large containers or back in the ground which i also do if i think a tree is looking a bit tired and forlorn, let's face it trees will grow better once there back in the ground !! Out of all these trees pictured i only have the viridis left now and all the others have been moved on over the years just don't have the room any more , so any trees that get dug up beware your days are numbered !! :) :) unless it's something really eye catching then i have a re think , already got this years trees ear marked for lifting.
