Nearly every tree or bush that is produced in a nursery using modern production methods leaves the nursery with destroyed primary roots (taproots). This is caused by the fact that the taproot has not enough space in a pot or plastic bag to grow vertically downwards.
When the taproot grows downwards and reaches the bottom of a pot or a plastic bag, he starts to grow in horizontal circles or even back to the top. Once you plant such a plant in dry areas, the primary root is not capable of penetrating deeply into the soil to find water.
On this page, you will find all the information about how you can recover the taproots, making it possible for your plants to grow in dry areas with the help of the Groasis Waterboxx® plant cocoon and without any need for irrigation.
Destroyed taproots and the consequences
Taxodium distichum sapling with circular growing destroyed primary root
Detail of destroyed circular growing primary root of Taxodium distichum sapling
Platanus occidentalis in Hortus Zodiacus botanical garden Holland, blown over by the wind 6 years after planting
Not recovered, twisted instead of vertically downwards growing primary root of Platanus occidentalis 6 years after planting
The photos above show you what the consequences are when trees are grown in pots/plastic bags and when they start to grow in horizontal circles. The photos show that when a taproot start to grow in a horizontal circle, he will never grow vertically downwards. Not even after years.
This means that a taproot that is growing horizontally, will never grow automatically vertical. The consequence of this is that a taproot isn’t able to grow vertically downwards to search for water deep in the ground. A tree with a destroyed circular growing primary root isn’t able to grow in areas without the use of irrigation.
How to recover destroyed taproots
It is easy to repair a taproot. Cut the horizontal part off.
The importance of the primary root for trees
The principal way of Mother Nature to reproduce and multiply is by sowing seeds on top of the soil. The seeds are usually transported and deposited on top of the soil by means of the wind or through the excrement of animals. The seed then starts to develop its primary root in order to find water, thereby establishing itself. Once the primary root has found water, the plant starts to develop secondary roots, and then starts to grow and evaporate.
Mother Nature's planting technique in 4 stages on one photo. As you can see, the taproot is growing vertically downwards.
How can I take care of good taproots?
Plants sold today, multiplied with modern production methods, are produced with deficient primary roots. The plants are grown in such a way that the primary root is touching the bottom of the pot or plastic bag in which it is produced, and then starts to grow in horizontal circles, grows up again or splits into secondary roots. In recent years, Groasis bought and photographed plants in over 20 countries, and wasn't able to find a single plant among them with a perfectly downwards growing primary root. All purchased plants turned out to have destroyed primary roots and over-developed secondary roots. Plants with such roots are utterly unable to survive dry periods or dry soil without the help of irrigation. Moreover, secondary roots are not able to penetrate deeply into the soil or break rocks.
Destroyed, split and upward growing primary root grown in plugs in Spain
Destroyed, split and horizontal growing primary roots grown in plastic bags in Kenya
A young plant in Dubai (before transplanting into its second pot) has a destroyed, twisted primary root.
After having been transplanted to the second pot, two smaller and thinner roots have
developed, but they lack the power of the original primary root.
Rounded and twisted growing primary root
Upwards (!) growing primary root
All primary roots are destroyed and grow horizontally under the plugs. These plug plants are
transplanted to bigger pots but as you can see, the primary root which is supposed to grow vertically
downwards is already destroyed, and is growing horizontally instead.
This is what perfect primary roots in a plug look like: downwards growing and white
How to recover destroyed primary roots from older plants with trees and bushes
In recent years Groasis not only learned to produce plants with perfect roots. We have also learned how to repair plants with destroyed primary roots. The secret to recovery is to prune the horizontally or upwards growing parts of the primary root. After pruning, the primary root resprouts and this newly sprouted primary root is growing vertically downwards again. The root is now capable of penetrating dry soil or rocks.
This is how you remove the destroyed part of the primary root
This is how you create a vertically downwards growing primary root
These are the horizontal growing primary roots that you have removed
Three months after pruning, new, vertically downwards growing primary roots have developed
Four months after planting: recovered vertically downwards growing primary roots
Which quality requirements are there?
There are several quality requirements young trees when planting must meet before you start planting. Below are they showing
- (Northern Hemisphere) Stem Diameter - 10 cm height of the planting period October to March: 5 mm;
- (Northern Hemisphere) Stem Diameter - 10 cm height of the planting period April to September: 8 mm;
- (Southern Hemisphere) Stem Diameter - 10 cm height of the planting period April to September: 5 mm;
- (Southern Hemisphere) Stem Diameter - 10 cm height of the planting period October to March: 8 mm;
- The stem has to be woody, not 'meaty';
- A maximum length of 20 cm is sufficient. If the plants are higher, they are pruned back to 20 cm;
- The taproot has to grow vertically downwards;
- The root must be white;
- The plants must be in the nursery for at least two months hardened in full sunlight.
You can find extended videos and photos about this subject here: