Hi, All my maples are in containers, and I would like to keep it that way. Most of them are in 7 gallon "smart pots" (fabric containers that are supposed to aid by aeration, root pruning etc). My soil mix is 50% pine bark, and 50% inorganic (turface, expanded shale), it drains well and holds up for 2 to 3 years atleast. Some of my trees are due for repotting after 3 years, these are 5 to 6 year trees mostly dissectums, 3 to 5 ft tall. The roots have filled their 7 gallon containers, but the trees themselves are not too big with less than an inch calliper. Can I root prune them and put them back in the same 7 gallon container? I do not want to bump them up to a 10 gallon as even now the container size look disproportionate to the trees. Is there some way to select a proportionate container size for a tree calliper or size? I have some 2nd year grafts that have filled out 2 gallon containers with roots, while the top is just a single twig. I know that the top will eventually catch up, but at the same time I do not want be bumping up the container size everytime. thanks, xman
Howdy Xman, That's a great question. I'd love to hear that someone has come up with a formula for JMs and container size! That has been a frustrating detail for me too. Personally, I do pot by root size, rather than top growth, but this practice hasn't produced any wacky twig tree in a giant pot yet...well, at least nothing so exaggerated that it looked super goofy for any length of time. In general, that means I can wait 3-5 years before having to re-pot, but should I see any circling of roots, or any hints of being pot bound - I pot up no matter what. Because I too will not be planting my trees in the ground any time soon, when I repot to a slightly larger size, I lightly root prune. I take out any big, woody roots the tree has sent out - as these are for stabilization in the ground and only take up precious pot space that could be occupied by tasty organic matter for my tree. You can definitely root prune and re-plant into the same container. This just requires a little more vigorous hair cut for the roots. I am kind of a weenie when it comes to this, (maybe I'll get more confident in time, or when my containers get too big to handle!) so I almost always pot up, albeit only by a small margin each time. There is a great photo essay about how to re-pot into the same container at EssenceoftheTree.com. They seem to be masters of the root prune - holding training sessions and all...AND their trees are beautiful! I do notice - and perhaps there are differing observations out there - that my trees seem, like goldfish, to grow to the size of their container. If I keep a tree in a smaller pot and simply root prune/re-plant in the same pot every few years, the tree stays small - maturing only in proportion to its container. I have seen when I take a tree that has been in the same pot for many years - even with root pruning - and pot it up to the next size - the tree gets noticably larger in a short period of time, eventually "maxing out" in the new size too. So, it seems that root pruning is a great way to manage tree size. I suppose that is the major principle of bonsai. (Ok, duh Katie!) Anyway, I suppose my point with this reply is to tell you that I, in my humble practice, pot when the roots tell me to pot - not so much the caliper or size of top growth. For me, the challenge to keeping JMs in containers is keeping the roots healthy; the beauty of the tree above is merely the result. I'd love to hear what others do with their container collections though. I am sure I can learn something! :)
Howdy Katie, I did see the re-pot video on EssenceoftheTree.com. I had visited a local maple nursery when they were potting up the bareroot red dragon trees that they had got from New Zealand. These about 3 ft tall, almost no branches, no roots except 2 or 3 thick roots that were about 4 inches long, no fibrous roots at all (probably since they were imported into the country). They all looked like tripod stands, but the owner assured me that all of them would grow ok. Of course they were dormant, but after seeing those I am not scared to root prune. I grow my trees in those ugly "smart pots", so I need to place them in decent looking ceramic or clay pots. So it becomes an issue everytime I pot up, since the old clay pots do not fit. It is interesting that you mention that the trees remains small if kept in a small container and root pruned. Having very limited space, this may be a good option for me. In fact I like trees that are small and stocky, I will use the same size pot this time for my 7 gallon trees and see how they fare. xman
X, I tried out smart pots this year (your recommendation) and they seem to be excellent for root health and development. My trees are all potted and I have a few 10+ yrs. I've never lost a tree to root pruning. I prune very aggressively taking up to 2/3 of the roots at a time. I always take at least 1/3. I return to the same pot if they are in 3 gal or larger because I don't have enough room or support for too many 10-15 gals. I agree with Spookie that the plants match above ground growth to the pot size (for the most part) and that they tend to get stocky from root pruning. Fall pruning of roots seems to pay off (here) with a better jump in spring so I've been pruning for a few weeks already. Lastly I might try some of the Niwaki pruning techniques I picked up from the Hobeson book. That book presents a very different aesthetic sensibility along with informative how-to pruning info. I've been practicing on pines and I am gonna get to work on a few acers. Your potting mix sounds like another good idea. Seems like using a inorganic approach makes good sense for pots. Just as it seems chemistry beats out biology for superior roots in pots.
Hi guys, Those smart pots look great. I have been looking around here in Europe but I have not found them (has anybody been luckier?). I've checked their website in the U.S. and they do ship to Europe, but I am wondering how heavy they are and how they are packed for shipment, have you received them by mail order? Could they also be used as liners for terracotta pots?, I was thinking of this since it would give the beneficial effect on roots while being hidden from sight ;o)) Thanks Gomero
Gomero, They are very light. I bought mine online and domestic shipping fee is nominal. They work perfectly as liners for containers. I have a P. bungeana cult in a black metal vase with the smart pot inside and large bark chunks in the spaces. It looks completely legit. I shall post a pic.
Gomero, Like Poetry to Burn mentioned you can place them inside terracotta pots, most of mine are. I like to get the terracotta pots slightly larger than the smart pots I want to put in them, and fill the space with pine bark chunks. Some of mine are just in the smart pots, these are especially placed in spots where the ground cover is tall enough to cover the pots. These bags and the 1/2 in-organic soil mix has really worked for me because I have hooked up containers to my sprinkler system, and I do not have to worry too much about over watering because the drainage and aeration is really good. xman
Bark of bungeana 'Silver Ghost' 'Silver Ghost' in a smart pot inside of metal pot (lightweight) 'Hanami nishiki' in a smart pot.
Gomero, I looked around also and didn't find any in Europe. They look great, drainage is obviously the thing. If you're ordering I'd love to get in on it. -E
