Should You Prune Your Orchid’s Roots

When it comes to orchid care, much attention is given to the care and preservation of their root systems. These extensive systems are highly sensitive to moisture and fungus, and fungal rot is the culprit of many unsuccessful orchids. 

With all of their care requirements, it makes sense to wonder whether there is ever a need to prune these important parts. While orchids generally do not require regular pruning, their roots might occasionally be a special case. Let’s discuss whether there is ever a reason to prune your orchid’s roots. 

The Long Answer

Any time you are working with a healthy orchid, I would typically advise against pruning. There are some circumstances, though, that make pruning a necessity for the health of the plant. Before we get into that, I would like to touch on some of the basics of orchid growth and care.

A Bit of Background

The orchid family is expansive, containing more than 25,000 species divided into about 850 genera. While there is much variation among these species, some similarities link many of them. 

While all orchids do not share the same growth habits, many of those that we keep as houseplants are similar. The majority of these plants are epiphytes. Epiphytes are plants that grow on other larger plants, which help support their needs. Don’t mistake these for parasites; epiphytic plants do not harm their host.

Because they have adapted to their environment, the root systems of these plants are sensitive to moisture. They get most of their moisture from rainfall and humidity. Because they don’t grow in soil, they must absorb water and nutrients from the air. 

Along with this adaptation comes vulnerability. Because of their absorption abilities, they are susceptible to infection by fungal and bacterial pathogens. Cutting them makes them more vulnerable, as it leaves an open wound. Generally, if your roots are healthy, you should avoid cutting or breaking them. 

I want to talk briefly about growth habits here, as there are two of them, and there are important distinctions. This distinction will come into play more when we talk about dividing your orchids. 

Orchids are either sympodial or monopodial in terms of the way they produce new growth. Both types have a central rhizome or stem from which all new growth appears. The difference is in the direction of that rhizome and the way it puts out that new growth. 

• Monopodial: Monopodial orchids have a vertical rhizome, and they grow continuously upward. About once per year, the plant will drop its lowest set of leaves and produce one or more flower spikes from between younger leaves. Phalaenopsis and vanda orchids are the most common monopodial orchids sold as houseplants. When looking at them, you will notice that it appears to be a single plant with a single root system. 
• Sympodial: Sympodial orchids have a horizontal rhizome. They send up individual pseudobulbs along this rhizome. Each of these pseudobulbs will produce a flower spike once in its life. After the flowers finish blooming, the pseudobulb acts as a nutrient storage system for the rest of the plant.

Some common sympodial orchids you will find include dendrobium, cattleya, oncidium, and laelia. When you view this plant without potting material, you will notice that each pseudobulb has some roots attached to it.

Armed with these facts, there are exceptions to discuss to the no-cutting rule. Let’s take a look at what circumstances may arise where pruning is beneficial.

Healthy Roots

Healthy orchids can grow quite large over time, and to match their size they need a larger root system. Because they take in most of the moisture and nutrients through this tissue, increased needs mean increased growth.

In addition to those they grow underneath, many orchids grow aerial roots. These grow from leaf junctures, above the level of your potting media. 

It may be tempting to trim these to keep a tidier appearance for your plant. Resist the urge! They are vital to the survival of the orchids and should remain intact. 

Damaged Roots

When it comes to roots that are unhealthy for one reason or another, the no cutting rule changes. There are several reasons that they could be in need of some TLC. Those that dry out, are rotten, or otherwise diseased or damaged are a threat to the health of the plant. 

Dried tissue is typically not a great cause for concern, except that they indicate a dehydrated orchid. If you notice that the aerial roots are drying out, you need to raise the surrounding humidity. If the lower ones are looking shriveled and brittle, your plant needs more frequent or more thorough watering. 

Rotting or diseased tissue is much more of a threat to overall health. Too much water or decaying potting media can lead to fungal rot. Tissue that is rotten will be dark, usually brown or black, and mushy. Healthy tissue is green or white, firm, and plump. 

If you leave rotten tissue intact, you compromise the rest of the plant. If your orchid has fungal rot, you want to remove the affected portions all the way to the top where they connect to the rhizome. Otherwise, they will spread to the rest, causing the crown to rot and kill the plant.

You may have heard that you should use various substances to treat the cuts you make when removing rotted tissue. Things like cinnamon and hydrogen peroxide are often touted as a good way to prevent disease from spreading. 

Unfortunately, while these things may stop the spread of the decay, they are more likely to desiccate the tissue. A faint dusting of powdered sulfur is all I would apply to cuts. This will help them to heal faster and cleaner. However, don’t overdo it as sulfur can be drying as well.

Repotting

When it’s time to repot your orchid, you will have roots to contend with. If your plant is in a container with any porosity, it’s likely to grow attached to the container. It’s important to handle these roots gingerly when you repot. 

Never cut them away from the container, rather water your plant well a few hours ahead of repotting. Allow the container to soak in a bucket or sink full of water to saturate the roots. This makes them more pliable and easy to work with without breaking or damaging them. 

Use a stiff card, like a credit card, to loosen any tissue that is stubbornly stuck to the container. Do your best to not tear them or leave open wounds. Choose a new container that is large enough to contain the entire root system. 

The only trimming you should do when you repot is damaged and diseased tissue. If it’s healthy, don’t cut it. Orchids don’t require any regular pruning at all. 

Dividing

Dividing a sympodial species is the only other reason you’ll ever need to cut the roots of your orchid. If you recall the difference between monopodial and sympodial, you’ll understand a bit of what I mean here.

Because sympodial species grow horizontally, you divide them between pseudobulbs, and you will have to divide them entirely. Even in this case, you truly want to do as little cutting as possible. 

Before you divide your plant, soak the container in water to soften the roots and make them more flexible. The objective is to hopefully pull them apart without tearing or breaking them. Slice between two pseudobulbs all the way through the rhizome leaving some attached to both portions. 

If you need to make any cuts to separate your plants, use a clean, sharp blade to do the cutting. A pair of harvesting snips or sharp scissors should do the trick. 

Final Thoughts

While the generally accepted rule is to leave them intact, there are a few reasons why you might need to trim your orchid’s roots. Any time you need to make these cuts, make sure to use a clean, sharp tool that you have good control of. Make the fewest cuts possible, and remove decaying tissue entirely.