I have small Ukigumo maple that is still in the original nursery pot (~10 months), when this tree goes dormant next winter, I am planning to repot using rootmaker or superoots. Root development is very important, wondering if anyone in this forum have tried any rootmaker or superoots (airpot) products. www.rootmaker.com www.superoots.com The 4 Inch Rule http://www.rootmaker.com/docs/4inchRuleWeb.pdf Thank you, Wilson
I know that Lucile Whitman uses with success, root control pots; a new technology, or alternative to the traditional nursery container. I think both of the pots you mention are similar in concept, just a different design, but I may be mistaken. Here is a link to her "About us" section on her website where she mentions the root control bags that she uses. She also has a link to the manufacturers webpage for more information: http://whitmanfarms.com/sample-page In her "how to" section she plants a tree from a root control bag: http://whitmanfarms.com/blog/planting-trees-from-root-control-bags-video The point I am trying to make is that there are maple growers in the industry that are successful in using an alternative to the typical black plastic trade pot. A technology that promotes healthy root growth. Based on the size of the tree in her video and the quality of the root mass, one may argue that it's a better way to grow in container cultivation. Personally, I like the look of a ceramic pot for my garden. But if you are open to the look of this pot technology, or if you are going to disguise it inside a decorative pot, it maybe the way to go. Aside from new technology, I never understood why nursery trade pots are black. It attracts heat and bakes / steams the roots. Maybe if another color was used (like light brown), one would wonder if the roots would stay cooler, healthier, and require less frequent watering.
These pots are not available in France, as far as I know. But the basic ideas are similar to a technique used by bonsai amateurs: - Free-draining mix, sometimes 100% inorganic, the nutriments are brought by fertilizers - Use of pond baskets : the roots come out of the holes, then dry out, they ramify inside the basket instead of circling the pot. It's mainly used fo conifers, most deciduous trees can be pruned back hard when done at the right moment.
With the bags the material constricted the outside of the root causing a sort of half root to grow beyond the walls, with the roots inside branching or at least thickening (eucalyptus) behind the point of constriction. So not all of the active roots ended up outside the container, unlike with roots growing out drain holes of conventional pots, for instance. This reduces the damage and shock when the plant is lifted. You can read about Whitcomb's findings and inventions in his books, libraries of colleges with horticultural programs have them here. He has been testing nursery production methods since at least the 1960's, I first read about his determinations in an interview that was published in Rodale's Organic Gardening magazine around 1977. After he retired from university work he put up the Lacebark Inc. web site, descriptions of his books and other information can be found there.
A cost-effective way to do this is to make your own out of landscape fabric. One advantage of this approach is that you can customise the diameter of the fabric pot and the angle of slope of the walls to just fit inside any decorative pot with a small air-gap all around the sides. I have been using this method for a couple of years now, and, so far, all of the Japanese maples grown this way have seemed to be very healthy. Some of the maples are due for repotting this spring and it will be interesting to examine the root structure when the time comes.
I also use landscape fabric to line the inside of wooden pots that either I make or I buy. You will find when you take your maples out that their external roots are basically glued to the fabric and you will have to pull hard to unstuck them. Another option would be to prune all the external roots to ease removing the plant. Gomero
My example is different to what (I think) you are describing in that I make a standalone fabric container slightly smaller than the outer container, thus maintaining a slight air-gap all the way around the perimeter of the rootball and inducing an air-pruning effect on the rootball. Your example sounds like the liner is in contact with the sides of the container all the way around (please correct me if I am wrong here). I imagine that in the places where the air-gap is breached by leaning on the container wall the roots will grow through and produce external roots as you describe. I will try and take some pictures when I get round to repotting some of the maples in bags.
