How the roots are pruned and how the aquarium plants are inserted into the substrate depends on the type of plant.
Basically, it is of little use to merely prune the roots of aquatic plants. The roots of aquatic plants have a different function than those of land plants.
After transplanting, the aquatic plants usually repel the old roots and form new ones. So there is no point in trimming the root tips before planting. The old brown roots have to be cut back to the healthy, whitish plant tissue.
Frequent repositioning does not benefit the plants at all because they have to form new roots every time. So you should always put each plant in its final place in the tank from the start. You have to make sure that the plants are not planted too deep. The root neck of the plant should be flush with the soil surface.
Planting Stem plants
Stem plants are offered with no roots anyway. The lower part of the shoot above the roots has already been cut off. The lowest pair of leaves is removed and the cutting is placed a few centimeters in the ground. You shouldn’t just push the stem into the ground. Stems of aquatic plants are usually soft and would bend or even kink. Then they rot within a short time and the stem plant dies. So you drill e.g. Use your finger to make a 3 to 5cm deep hole in the ground, insert the lower part of the plant into the hole and then press the substrate against the side of the stalk so that the plant gets a firm hold.
Unfortunately, as long as they have not yet formed new roots, these stem plants have little chance of anchoring themselves permanently in the ground. Therefore, they sometimes float back to the surface. It is important that the stem plant is not planted in bundles. Even if they are to form a group, each cutting is placed individually in the substrate. The distance between the individual cuttings should be at least one leaf length.
Stem plants are usually offered as a plant bundle with rock wool or foam tape wrapped with a lead tape, more recently with a ceramic ring. As a result, the plants are weighed down to such an extent that they stand vertically in the sales tank, even without being planted. However, this should by no means tempt you to plant these plants in your own aquarium as a bundle with a ceramic ring or even lead tape.
Basal aquatic plants that have only thin and few roots, such as the Vallisneria, Sagittaria species and smaller Amazon sword plants, are shortened only a few or not at all, as they need the roots to anchor in the substrate until they slowly form new roots.
Planting Rosette plants
With rosette plants – this includes e.g. the water goblets (Cryptocoryne) and the sword plants (Echinodorus) – the roots are shortened to 2 to 3 cm, then pressed deep into the ground and then pulled out of the ground as far as they were previously offered for sale in the culture pots. The rhizome points vertically downwards and soon forms new roots again.
Planting Rhizome plants
When planting rhizome plants, care must be taken to ensure that the rhizome is not completely covered by the soil substrate, otherwise the plant will begin to rot.
Planting Bulbous and Tuber plants
Onion and bulbous plants are usually sold in pots and rockwool in the aquarium trade. These have to be carefully removed. If there were several plants in one pot, then the individual plants are divided up. Onion plants such as the hooked lilies of the Crinum genus are only used to the extent that the onion protrudes halfway out of the substrate. Tubers, on the other hand, are planted in the ground up to the beginning of the planting shoot.
Planting Ground cover plants
In the case of ground cover plants (e.g. of the genus Eleocharis and Glossostigma), on the other hand, rock wool is sometimes used as a ground anchor. First remove the potty and some of the rock wool. The rock wool is shortened to a length of 2 cm. Then you divide the plants together with the remaining stone wool adhering to them into several portions and place them at regular intervals of 1 to 2 cm on the entire area that will later be covered by this plant lawn.
Epiphytes – this includes most ferns and mosses – are tied to stones or wooden roots with a fine wire or thread until they have found sufficient hold in the ground. You can get aquatic mosses in specialist shops as colonies on small ceramic plates or stainless steel grids. This makes it easy to place these cushions anywhere in the aquarium. Soon the aquatic moss will overgrow the artificial substrate so that it is no longer visible.
Plants that have so much buoyancy due to their large leaves despite having a larger rootstock that they could float to the surface of the water are not buried deeper. Instead, the rear part of the rootstock is inserted at an angle and pushed a little deeper into the ground, while the root neck is flush with the ground. Then you weight the root stock with a stone until it finally grows.