How to Trim A Cactus Plant | Detailed Guide

When Should You Trim A Cactus? Signs to Look Out For

Overgrowth

While most cacti grow slowly, it can be overwhelming to keep up with the growth of some jungle species, such as Acanthocereus, Epiphyllum, Hylocereus, etc. Also, some cactus sections can develop more quickly than others, resulting in an asymmetric shape.

Many have reported their cactus growing vertically at an abnormal rate instead of branching. Pruning can be very helpful, especially in these cases, as it also creates an opening for the new branches to form on the side.

You may also need to trim a cactus if it’s becoming too tall for its pot to keep it from toppling over.

Rotting

Cactus can rot in two ways:

Tip Rotting

Also known as top-down rotting, tip rotting is when the plant starts rotting from the top. Initially, the tip becomes brown and mushy, which then transfers to the lower section. Tip rot spreads very fast and doesn’t stop until the whole plant is ruined.

The biggest culprits for top-down rotting are disease, fungus, and collected water in the rotten spores.

Bottom-Up Rotting

Sometimes, the rot can start at the roots and spread up. Bottom-up rots are dry and spread slower than tip rotting.

With tip rotting, most of the time, the only thing you need to do is cut out the rotten part. But fixing bottom-up rot is more complicated; you may even need to repot the cactus after removing the affected root.

Pest Infestation

Many pests, such as mealy bugs, fungus gnats, spider mats, etc., can enter your cacti. They spread out fast, and the results may be more catastrophic if they reach the plant’s roots.

When you see some pests, you should try to clean them with water or cotton swabs dipped in alcohol or insecticidal soap. If the problem still persists, call in a professional service. And if even that doesn’t work, removing the affected area and isolating the rest of the shrub is the only solution.

Growth of Unwanted Sprouts

Many Barrel and Rosseta cactus can branch offsets, also known as pups. You can remove the pup from its parent and replant it for new vegetation.

Unwanted sprouts can also be in the form of fruits and flowers. While fruits fall off on their own, you may want to trim the flowers to give your shrub a new look or remove dead stalks. 

How To Trim A Cactus Plant: Step By Step Guide

Things You Will Need

• A serrated knife and pruning shears – You may need a saw, depending on the size of your cactus. Make sure the tool has sharp and pointed edges and is of comfortable size for your hand.
• Rubbing alcohol or 10% bleach solution to sterilize the blade
• Long, thick clothes and shoes to protect your body from being exposed to cactus needles
• Waterproof gloves to protect your hand and avoid irritation from milky saps
• Water-based marker to mark the area you need to trim
• And finally, an old newspaper or a plastic or paper sheet to cover the area around the newspaper to pick the cactus remains
  

The Process of Pruning Cactus

Step 1: Check for the portion you need to cut. This can include overgrown, rotten, or diseased sections of the cactus.

Step 2: Make an action plan. You have to move in from the outer branches to the stem. Try to envision how the plant would look after trimming off the part you want to remove.

Step 3: First, remove the limbs. This includes wilted and dead parts and the flowers blocking your way to the inner stem. Some of these parts can easily snap off, but be careful not to touch the inner branch.

Step 4: As you reach the stem, cut the part with a tong if it’s small. If it’s large, you can hold it with a rope and cut it off. Sometimes help from a second person is needed.

Step 5: Use a marker to mark the top and bottom parts of the cut cactus if you wish to replant it.

Step 6: Collect all the remnants and dispose of them appropriately.

Things to Remember

• Cut at a slight angle to not disturb the sap.
• Start cutting from the narrowest point if you’re dealing with an overly big plant. 
• For diseased plants, make sure to dip the knife in a sterilizer after each cut.
• Use shears on branches and knives on narrow areas. 
• If possible, don’t cut too much of the plant at once. It may affect the balance of nutrients as the shrub will be losing too much sunlight and water from that section.
• If you haven’t necessarily exposed your blade to any diseased area, you could clean it with soap and warm water instead.
  

Cutting A Padded Cactus

In addition to the above steps, you need to remember the following things while trimming a padded (prickly pear) cactus:

• Remove the entire pads that you don’t want, not just part of it. 
• Only cut at the intersection of the plant and not across the pad. 
• Trim the parts that you can reach, and ensure that the pad falls outside the plant and not inside it.
  

Trimming Columnar Cactus

Here are some additional tips for cutting columnar cactus:

• Using a saw can work better than shears.
• Be very careful while removing columns as they store water and absorb sunlight. Don’t remove too much at once.
• Make preliminary cuts before taking the section off.
  • The first cut should be some inches above the part where you wish to saw.
  • There should be another cut but in a different direction from the point of the first part. These cuts will help balance the fall of the column.

For overgrowing plants, remove the stem exactly at the growth point.

Things to Do With Cut Cactus

Here are some things you can do after trimming the shrub:

Replant

You can replant padded cactus pieces and pups immediately, also known as propagating, and they will start to root.

On the other hand, columnar cactus pieces require some days to callus.

Callusing A Cactus

• Remove all the unhealthy and moist bits from the stem.
• Dry it in a clean towel for about 5 days. Also, turn the pieces regularly to avoid rooting at the side. Avoid sunlight. 
• Fill a pot with cactus soil, stones, and volcanic rock. Plant the cactus in there. Don’t water until the root appears, generally at least 10 days.

Note: It may take several weeks for the root to appear. You can lift the plant and check occasionally. But make sure that you only water after the soil is completely dry.

Use as Compost

Fruits and flowers of cactus can be used as compost. For doing so, add the cut part to the soil and then let decompose on its own. This way, your cactus will be able to give life to another plant!

How to Dispose of a Cactus After Trimming It?

Cactus is a very stubborn plant, so disposing of it can sometimes be a challenge. Here are some ways you can safely throw away the trimmed part:

Throwing Away with Garbage

Cut the cacti into various pieces and then place them inside thick cardboard. Make sure there’s no sunlight inside. Then, you can throw it away along with other waste. 

Some cities can have their own regulations and guidelines for throwing away cacti. Here is an example from the City of Redding in California.

Intentionally Overwatering

Overwatering the cactus causes it to become moist and rot. Then, you can use the remains as compost.

For overwatering, place the plant inside a pot and fill it with water. Eventually, it will lose its hardiness and die.

Chemical Disposal 

You can dispose of the cactus with an herbicide as well. These chemicals are meant to be sprinkled on top of plants to kill them and are readily available online and in your local gardening store.

If you don’t want to use chemicals, mix in two tablespoons of vinegar, two tablespoons of rubbing alcohol, and a tablespoon of dish soap to a liter of water. This homemade herbicide is safe but can take a couple of applications to be effective.

Be Careful With the Cactus Root

If you are removing the cactus completely, you have to find the center of the root. This can be confusing since inside the soil, the root spreads across horizontally. Again, be careful and wear strong boots – the cactus spines can easily penetrate your slippers if the sole is soft.

Conclusion

You rarely need to trim a cactus, but when you do, it’s a little different from other plants. You’ll need to be extra careful since the plant naturally has spines and sap to protect it from predators.

But most importantly, make sure you do all the basics – using the right tools, sanitizing blades before using, and disposing of the remnants correctly.