Cutting orchids: how to deal with roots / aerial roots?

If an orchid is cultivated in substrate, it can only grow on “normal” roots or develop additional aerial roots. If an orchid is cultivated with bare roots, only the aerial roots are available for supply anyway. With which care and in which environment an orchid is cultivated, with or without a substrate, also has a decisive influence on whether earth roots, aerial roots or a combination of earth-air roots develop splendidly or whether corrective maintenance interventions are required more often.

In a German apartment, an orchid never grows completely in its dream environment (to put it in a friendly way). The living room with a German climate is just not a rainforest – even if in theory every private person could create an artificial rainforest climate in the living room today because the technical possibilities allow it, that is of little practical use: If you “miss a climate” in your living room in which the orchid feels comfortable, the wallpaper is making waves on the walls from the sheer moisture and after a short time you have the feeling that you can no longer breathe, below 90% humidity the world is not all right for an orchid in the long run.

If people want to live with these special plants in a room with an indoor climate that is tolerable for humans, that always amounts to a compromise for the orchids. The best care can tear a lot, but you have to assume that an orchid is statistically more on the verge of a lack than “suffers from too much vigor”.

Therefore you should be extremely careful with every pruning of an orchid, above all the orchid needs every small piece of root to ensure the supply; regardless of whether it is earth roots or aerial roots. For the pruning of the orchids themselves and the roots of the earth, this means:

Orchids in earth culture: pruning and root pruning

Many orchids naturally grow in soil and therefore like to grow in substrate “in exile”. So quite normal, roots below and trunk and shoots above, leaves and flowers, with a rather unique growth behavior: Orchids never grow right up in the tropical forest, then they would somehow have to float in the treetops, but in a more or less light-based “basement”. The genetic growth program of the plant is geared towards this, it strives for the light, and so consistently that new shoots only develop at the top, while the lower leaves say goodbye after a certain lifetime.

That is why an orchid “around the top” does not normally need any pruning at all, or the pruning of above-ground parts of an orchid’s plant is only necessary to correct undesirable developments.

We will come to the individual possible undesirable developments in a moment, the general rule for trimming in the areas of flowers, leaves, shoots and stems:

• An orchid is not a wood that reacts to cutting with increased budding – scissors are always the very last solution
• Because the cut usually only interferes with the efforts of the plant to produce new shoots
• Neither flowers nor leaves need tuition when they begin to wither
• Orchids sometimes form complicated anchors and often also draw nutrients from wilting parts
• Therefore it is better to wait until the withered parts of the plant fall off by themselves
• Even if an orchid throws everything off, the now bare trunk does not need scissors
• But time and rest until new shoots form, which can take a few weeks
• For example, with orchids with multiple shoots, where the fallen flowers leave an empty stem
• If this looks nice and green, it should not be removed yet; new flowers often form again

You can help the plant with the following (incorrect) developments by pruning:

• Single-shoot orchids bloom on a main shoot that stops growing after the vegetation phase
• Instead, the orchid sends a new sprout up from the rhizome
• When the old flower shoot is visibly completely dead, it is cut deeply
• Stems of multi-shoot species that have become completely brown and dry should also be removed
• If only part of this has dried up, only this part should be cut away
• New flowers can develop from the still living piece
• Plant parts that have stunted due to incorrect care are cut away
• These are usually suitable for cutting because they look yellow, rotten, or brown and dry
• If the appearance of the lower leaves that are drying up disturbs, gently pulling them often helps
• If the loss of leaves gets out of hand, the whole plant should be checked for diseases and pest infestation
• If the trunk is diseased, it can develop yellow to brown discoloration
• Then it can be shortened to a healthy green, but will not necessarily survive that
• If in doubt, it is better to wait a bit here as well, to see whether the drive recovers
• But don’t wait too long either, dead plant matter pollutes the orchid
• Rotten, old orchids can be rejuvenated by pruning the roots a little more resolutely

Roots are never pruned unless it is necessary to correct undesirable developments. In the case of orchids in soil culture, there is a risk that the roots will develop incorrectly in two directions: The growing medium – hydro-clay balls, coconut, cork chips, perlite, bark chips, clay lumps, styrofoam balls, vermiculite or mixtures of these and similar substances – gives the plant a hold, but also stores it in a very similar way like the sponge-like root skin the water.

With this type of culture, whether the earth roots develop well depends above all on the fact that you provide the roots with as much moisture as possible. If the orchids stand in dammed water even for a short time (which they do not know from their homeland, the rainforest sounds like a lot of rain, but is still structured in such a way that a lot of water always drains off from above), earth roots like to start to rot. If you water too hesitantly, fine root ends will dry up. If the orchid is not cultivated with enough moisture, it will often form aerial roots in addition to the earth roots in order to search for nutrients in the air.

The same applies to the roots that only visibly and safely rotten or dried out parts should be cut away. The best time to prune the roots has come when the orchid has to be repotted anyway. It always has to be repotted when air or other roots noticeably no longer fit the planter in size (if possible, wait until after the flowering period with repotting and pruning, the orchids then have more resistance). Take the next larger flower pot, containers that are too large do not give the roots enough support.

If an orchid in earth culture has formed aerial roots “out of self-defense”, these do not correspond to the taste of every carpenter from a purely visual point of view. Even so, you should try to live with these aerial roots because cutting them away “could put the orchids into agony for good”. However, you can use the new, additional roots to make it easier for you to look after your orchids in the future: In the future, spray the aerial roots above all and the whole orchid secondarily – if you can always manage to keep the aerial roots a little moist do a lot to ensure that the orchids feel comfortable in our climate.

With moisture freaks like the Vanda orchids, you can even get rid of a typical difficulty in keeping them with this tactic: Vanda orchids prefer to have a constant humidity of around 90 percent around them, which is only possible in the living room of Vandas in pure earth culture create is when you keep spraying them with water. When your living room slowly resembles a damp grotto, the Vanda orchid begins to feel good. However, there are experience reports that when you spray the aerial roots in particular, you need to distribute a little less moisture in the air, with the result that humans and orchids can live happily together.

The right tool

If you read that you should clean or even disinfect your pruning tools, you are correct insofar as basic hygiene must be observed when handling plants. Exactly the hygiene in the household that ensures that a few salmonellae bought with the chicken stay on / in the chicken and die with it in the pot / oven at at least 75 ° C (at least 10 min core temperature) and not over the cutting board, knife, etc. .ä. distributed through the kitchen. Where they survive for weeks without being attacked by vinegar cleaners and perhaps multiply well on damp surfaces in the warmth of a heated or warm summer kitchen. With plants, the main thing is not to spread diseases and fungi.

If the cutting tool has not just been used to cut a completely fungal plant or the like (then boil in water for at least 5 minutes), normal washing is sufficient, the usual household germs are also floating around in the air and are your orchid anyway already known. Incidentally, these germs can also concentrate in the stones, expanded clay balls, etc. of the substrate, which should therefore be washed thoroughly from time to time. If you wash your hands thoroughly before snipping around at the orchids, you have done enough for the hygiene (and please only use normal vinegar cleaners, washing-up liquid, soap; if the medical disinfectants are not reserved for the medical sector, there is a risk the development of multi-resistant everyday germs).

In the case of sensitive creatures such as orchids, it is advisable to supply the interfaces that protect them against drying out and infection. If you had to cut away half the trunk of a rare orchid, it may be worth buying a sealing paste (after consultation with specialists, when pruning street trees, for example, no sealing is required today because the fungi that are already in the plant tissue are more likely to be Blossom ”brings). Mini-wounds can be powdered with traditional gardening agents such as coal, lime or sulfur (powder) and thus adequately disinfected. If you enjoy semi-alchemical mixes, you will also find great recipes on the Internet with tannin paste from the bark of mangrove trees (long-used natural tannin with a high tannin content of up to 42%),

Pruning bare-rooted orchids

Many orchids prefer to grow with their roots in the air and are therefore cultivated in hanging baskets made of wire mesh or cord or in airy glasses with a wide opening.

In the area above the ground these orchids are pruned as just described, for the aerial roots the following applies above all: Spray with water and only prune when it is really impossible to avoid. Because these orchids only feed themselves in the hanging basket by filtering water and nutrients from the air. In the glass you can usually “drink your fill” every two weeks, but the water that has been filled up is poured off again when no more air bubbles rise from the root area.

These orchids urgently need their aerial roots for their nutrition, should never dry out and only be carefully pruned if something is completely wrong:

• Completely dead aerial roots should be cut away
• Heavily overgrown aerial roots may be shortened so that the orchids do not lose their hold in the culture vessel
• In addition, the nutrient supply of the orchids should be checked, proliferating aerial roots proliferate from hunger
• If enough nutrients have been supplied, compaction of the substrate can make nutrient absorption difficult
• Rotten parts of the aerial roots or roots that look sick should be removed
• When old orchids no longer bloom, the roots can be pruned a little more radically, which rejuvenates the plant

Everything else stays better on the orchid, including dried out aerial roots – as long as they have not yet conquered the living room, they give the plant more stability in the planter. However, dried out aerial roots warn of a lack of nutrients and too low a humidity level, so the spray bottle should be used here regularly, or you should set up evaporation containers under the orchids. Here, too, it is best to prune in the course of repotting, which is due when more aerial roots grow out of the planter than there are in the container.

Conclusion
Orchids do not need regular pruning, but good root care, because foreign guests find it difficult enough to take care of them via roots and aerial roots in the local climate. If in doubt, this also includes pruning the roots, which should, however, be carried out with a high degree of caution. Even with the aerial roots, which are often underestimated, but just as much contribute to the care of the orchids as the roots in the earth.