The growing conditions of plants are fundamental for the quality of their roots.
Growing in Open Ground
This growing method, less and less used for retail sales, is still very much used by professionals, especially for medium- and large-sized plants. It’s the best way to produce sturdy, dense, and well-shaped trees.
Growing in Containers
This is a very popular method, as it gets rid of the inconveniences of open ground, as well as extending the planting season, as all the roots are contained in the pot, which you simply remove the plant from before putting it in the ground…..but:
- Inconvenience No 01: the plants are not very dense, especially if they are a few years old (and on condition that they are repotted every year in a bigger pot!).
- Inconvenience No 02: some plants with a strong implant form what we call a “root spiral”: their long roots turn in circles at the bottom of the pot and must be cut before planting in order to prevent auto-strangulation. These plants shouldn’t be grown in containers…nonetheless, a lot of people do this!
Warning: even plants grown in the open ground may have spiraled root!
Most young plants with delicate growth are multiplied in pots before being planted in the ground, which means that they have already spiraled in a very small diameter. This is heresy! Unfortunately, this is widely practiced in ornamental nurseries.
To overcome this inconvenience, there are procedures to avoid roots from spiraling:
- The biodegradable peat pot for young plants
- The forestry pot for trees with pivotal roots
- The above-ground basket for trees and conifers 2 or 3 years old.
The forestry pot (20cms. deep) allows the pivotal root not to bend when it touches the bottom of the container.
The peat pot and the above-ground basket (1 to 4 liters) both allow an “aerial encircling” of the roots. That is to say that the roots dry out when they grow outside the walls of the container, which encourages the growth of other roots on the inside, which in turn grow out, and so forth…
Which Plants are Most Likely to Be Affected by this Phenomenon?
Those whose roots don’t branch out much, especially those with pivotal roots. Indeed when there are few roots, they tend to lengthen, whereas dense, thin their branch out much more, at the same time thickening less. Spiraled roots must be avoided, especially for future big trees.