Building a Better Container

As most of you know, roots circling around a container isn’t considered a good thing.  And so people try various things to control circling roots.  One of the more creative horticultural minds out there, Carl Whitcomb, a guy why basically got sick of academia and went into private industry (and, as far as I can tell, loathes peer review and the whole process of publication), decided to see what he could do about making containers that don’t encourage circling roots.  He came up with a number of designs, but my favorite is the RootTrapper.  The container is made of a flexible cloth which roots get lodged in, preventing them from circling.  Not that I’ve never seen a circling root in a RootTrapper, it’s just that these circling roots are extremely rare.

A row of elms in RootTrappers

A cut open RootTrapper

This is one of those innovative products that really works and it surprises me that so few people use this growing system.  Yes, it’s a bit more expensive than standard containers, and yes, it does take a little more effort to take the tree out of this container than a smooth sided one.  But man, I’ve never seen a better root system come out of a container than those which you get out of these.

7 thoughts on “Building a Better Container”

  1. This sounds like a great idea.

    This reminds me of a question I’ve been meaning to ask. My wife and I are about to buy a house in Oakland, CA. This means leaving behind our garden, and our fruit trees which are just starting to bear. We want to plant a number of trees at the new property, but we won’t be able to actually do so until we prepare the site a bit.

    In order to get the new trees to size up as quickly as possible, we were thinking about buying trees in pots now (local nursery sells them in 10 gallon pots) and holding them for 6-9 months before planting them, potting them up if that’s indicated.

    Can you tell me, is this a good strategy overall? Would this be a good application for the Rootrapper? How long can we hold, say, an apple tree before doing so will compromise its future development? What size pot should we plant up to if we are going to do this?

    We have lots of gardening experience but limited experience with young fruit trees.

  2. Fruit trees are typically tough transplants, and harder the larger they get. Buying an appropriately sized tree in a ten gallon pot and transferring to a 15 gallon roottrapper would work fine, but I wouldn’t bet that, if properly cared for, the tree wouldn’t do just as well if you put it directly into your soil — after you have it tested of course!

  3. Well I really wish that the Magnolia stellata that I had to plant today in a client’s garden had grown in one of those pots instead. This specimen was such a mess that the original circling roots from its time in the original 1 gallon pot were hidden by a whole other root mess that filled in the spaces since it was repotted into a 3 gallon. Plus, of course, there were all the roots that had to force their way upward to make up for the 2 inches that the rootball was buried in the second pot. I really wish I had taken a pic of this! I did what I could with it and cut and teased out where possible. It’s in the ground now, no soil amendments, well m
    ulched with wood chips and I can only hope for the best. I would rather have it die next week than watch its slow demise over the years to come…

    And I will comment on GreenEngineer’s question about fruit trees: I used to work at a garden centre and those fruit trees in 10 gallon pots are likely just the leftovers that didn’t sell while still dormant and bare rooted in the very early spring. You will be paying at least twice the price for a tree that most likely will be badly stuffed into its new container because those bare root trees come with nice wide horizontal roots. I spent an afternoon at that garden centre trying to figure out how to stuff the leftover fruit trees with 24 inches of shallow horizontal roots into containers that were 10 inches wide and 18 inches deep. I probably created ugly messes and most of those trees are likely dead or dying now, 15 years later. But I didn’t know better and neither did anyone else I was working with. Knowing what I now do – thanks to The Garden Professors! – that bare root is the way to go I would suggest that you wait until you can purchase the best bare root trees you can find while they are still dormant. If you make arrangements with the garden centre to arrive on the day that their shipment arrives and choose your specimens before they temporarily heel them into whatever they heel them into you can choose the one with the best root structure and overall form. I would be very, very careful about buying trees or shrubs in large containers from garden centres unless they are buying them already that size from a reputable commercial grower. Most large pots of trees or shrubs at most garden centres that I’ve seen are just badly repotted leftovers, possibly from many seasons past, stressed out but kept alive with regular injections of water and synthetic fertilizers.

  4. I think that there’s a bit of over reaction here. I see many trees in garden centers that are grown in containers, and most are not leftovers, stuffed in a pot, or stressed. There’s little question that many container grown trees are root bound, but this allows us to plant more than the month or two of the year that we are limited to with bare root, and for trees with weak roots I would prefer a root bound pot to a loose and broken root ball. I can fix root bound, I can’t fix broken, and short and long term survival is generally good with container trees, although they take more attention to watering in the nursery and once planted. As Natasha makes a critical generalization about the quality of container trees, she still buys them, so I don’t expect that she really finds them as objectionable as she implies.

  5. This seems similar to pots I’ve seen that have little cones facing outwards all the way around them. There are little holes at the tip of each cone so the roots of the tree get aerial pruned as they grow out of them. The cones also stop root curling. I like this root trapper design though – it’s a bit more environmentally friendly than plastic pots.

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