If the plants get out of hand in the aquarium, they must be thinned out, shortened or cut back. Smaller, more frequent interventions in plant growth are better than a one-time, strong pruning that could upset the biological balance. In addition, the aquarium always makes an optimal impression with regular plant care.
Depending on the type of plant and growth form, the pruning process must be different:
Trimming Stem plants
The upper shoots of stem plants are shortened – at the latest when they reach the surface of the water. Stems with flower buds, on the other hand, are allowed to grow further, as they can often only fully develop their inflorescence when immersed, i.e. above the water surface. The remaining shoots are cut back as deep as possible to just above a leaf. These shoot pieces can then be used as head cuttings and directly replanted. Within a short time they will form their own roots.
Side shoots often form at the interface, giving the stem plant a bushier, compact appearance with its branches. These side shoots can also be used for vegetative reproduction if they are long enough. The cuttings are always placed in front of the existing stem plants in order to get a staggered plant structure with a depth effect.
Trimming water moss and ground cover cushion plants
Water mosses and cushion plants that cover the ground are “mowed” evenly like a lawn, i.e. cut back. They usually grow back very quickly. Shortening the height of the lawn pads promotes surface growth. Frequent trimming creates a dense cushion of moss. Cut pieces of moss can be tied up at another point with somewhat transparent fishing line.
Trimming water goblet
In the case of the water goblets (genus Cryptocoryne), only yellowed or damaged old leaves are removed. If the group becomes too dense and the individual plants compete for space, then you have to remove individual plants completely from the group every now and then.
Trimming Rhizome-forming aquarium plants
Rhizome-forming aquarium plants usually grow slowly. However, if they threaten to occupy large parts of the aquarium with the help of their long rhizome runners, the plant is shortened by carefully removing the rhizome and dividing it between two eyes. These eyes are the buds from which a new leaf base develops.
Each rhizome section can be replanted in another place. It is important that each piece of rhizome contains at least one eye. The rhizome pieces are planted out on the surface. They must not be completely covered with the soil material, otherwise they will rot. Pieces of rhizome, like those of the Java fern, can also be tied on a bog root or a stone with a piece of cotton thread or a piece of wire.
Trimming Rosette plants
If rosette plants reproduce too much due to their runners, then you have to thinning them out so that they do not mutually take away the light with their leaf rosettes. Old, decaying or heavily algae-covered outer leaves of the rosette are carefully cut off above the leaf root without damaging the plant.
If the aquarium plants form daughter plants on their long runners, the adventitious plants are only separated from the mother plant when they threaten to grow into neighboring groups of other plants. Old mother plants have to be removed every now and then and replaced with runners.
Trimming Floating plants
Floating plants serve as powerful nutrients in the aquarium to avoid over-fertilizing the water. However, that is why they spread particularly quickly on the water surface. So that they do not shade the aquarium too much and hinder the exchange with the air, they must be regularly lighted. Pruning is hardly possible with floating plants.
Smaller floating plants such as the water and pond lentils or the floating fern are skimmed off with a net, while larger plant species such as the sumatra fern or the mussel flower are removed individually.
The pruning of aquatic plants is of particular importance in aquascaping. A passionate aquascaper is actually constantly on the move with planting scissors in the natural aquarium to bring an underwater landscape into the desired shape.
It is no longer just the growth behavior of the individual plants that is important, the overall impression is decisive. For this purpose, the plants are laid out and trimmed according to the rules of the golden ratio, which comes from architecture. But not only when the plants have grown too big, as soon as the ice nets in the aquarium, are they cut back with long scissors so that a harmonious overall impression is created.
In the nano aquarium, too, thinning and cutting back has to be carried out more often, since the space available to each plant is particularly limited here.
Amazon sword plants (genus Echinodorus), as well as bulbous and tuberous plants (tiger lotus, hook lily, etc.) are trimmed by removing the outer leaves every now and then.