Why Do Cactus Spines Fall Out? 3 Reasons! (Is It Normal?)

If you own any cacti, you’ve probably been punctured countless times by now. It’s normal to be occasionally pricked by a rogue cactus spine but do they ever fall out or come out on their own? Let’s go over it.

Cactus spines do not naturally fall out on their own but will sometimes come out after fake flowers are removed and after being repotted. In comparison, glochids, or fine cactus spines, dislodge easily and are more likely to fall off upon direct contact.

While it might seem like those spines are falling for no reason, there probably is a good explanation for it. Here are all the reasons your cacti might lose their spines!

1. Removal of Fake Flowers

Cactus spines can fall out when fake flowers are glued onto spines or areoles and harshly pulled off. The act of ripping off hardened glue can damage cacti spines and cause them to drop. Melting the glue and wiping it off can prevent spine loss.

For some reason, nurseries will sometimes sell cacti with fake flowers. What’s tricky about this is that they sometimes glue real flowers on the cacti to further maintain the illusion of a genuine flowering cactus.

Luckily, you can tell these flowers are fake when there are large mounds of hardened yellow liquid at the flower bases. This is not sap but rather hardened glue. Cactus flowers do not release sap.

Not only you have to remove the fake flower, but you’re also likely to harm the spines in the process. Oftentimes, these flowers are glued onto an areole or spine cushion to help make it look more realistic.

If there are any cactus spines stuck in the glue, they will inevitably be pulled or knocked out in the process.

But don’t lose hope—you can remove the fake flowers while minimizing the chances of ripping off the spines from your cactus!

To start, snip the fake flower as close as you can to the glue to prevent it from obstructing your view. If you own a hairdryer, try to set it to medium heat and use it to melt the glue. The melted glue can be carefully wiped off.

It might get messy, but it will be much gentler than simply tearing off the hardened glue and taking off a few spines with it!

2. Repotting

Cacti spines can be damaged and fall off while they are being repotted. To prevent cacti spines from falling off during repotting, lay the cactus down on paper or cardboard and avoid touching the spines.

The act of repotting can be pretty harsh on plants. Your cactus is not immune to this, especially when it’s wrapped in paper or tightly gripped with tongs while it is being released from its pot.

Unfortunately, the protective practices we take to shield ourselves from cacti can damage their spines and break them off the plant. Nevertheless, spine loss can be reduced if you’re careful enough.

When repotting cacti, it’s best to do it as gently as possible to avoid damaging the plant. Lay the cactus down on a piece of cardboard or paper and focus on easing the pot off rather than pulling the plant.

Check out our article on Repotting Cactus for more information.

Old cloth can be used as well but keep in mind they’ll probably have some spines in them afterward. Remember to clean the workspace after repotting any cacti, especially those with glochids.

Glochids are minuscule spines that easily lodge into the skin and can be difficult to see with the naked eye. So with that in mind, be careful not to sweep any of these tiny spines into the air!

3. Direct Contact

Tiny cactus spines, glochids, fall off easily upon direct contact. Cacti with glochids must be kept in low-activity areas and placed in heavy pots to prevent them from toppling over and dislodging spines and glochids.

There are very few instances where cactus spines might fall off. Glochids, however, come off with little effort.

I will talk about this more in-depth later in the article, but glochids are essentially smaller and finer versions of spines. They fall off very easily; even a light touch can cause these painful hairs to fall off.

Our homes and gardens can be hectic places. You might bump into a plant while walking by or accidentally touch it with a watering can.

For times like these, it’s not surprising when glochids get dislodged and drop off the plant. The best way to avoid this is to place cacti in low-traffic areas and away from pets and children.

If your cactus tends to fall over easily, consider using a heavier pot made of terracotta or clay. This will help stabilize the cactus and keep its spines and glochids safe.

This terracotta pot on Amazon is great for cacti!

What’s the Difference Between Glochids and Spines?

The 3 main differences between spines and glochids are that glochids are smaller, detach more easily, and typically only grow on Opuntia and Cholla cacti.

You might be wondering at this point how spines and glochids are different. While they are both technically spines, glochids have key features that set them apart from the traditional spine.

If anything, glochids can be worse than them due to how significantly more painful they can be to touch! The search for a method to safely remove glochids from prickly pear fruits has been so great that scientists have even tried to remove them with lasers.

It might sound like it’s too much, but after learning more about glochids, you’ll understand why such techniques were considered.

1. Glochids are Smaller Than Spines

Although glochids are technically spines, they can be less than 0.5 cm big compared to cactus spines which are 1.5 cm. Glochids are hard to detect and can be impossible to see without magnifying glasses.

Regular cactus spines are an average of 1.5 cm long. They’re usually very stiff and pointed. These are the spines that typically come to mind when you think of a prickly cactus. But there are other types!

Opuntia cactus can sometimes be seen growing very small and fine needles in each areole among the usual spines. These smaller spines are known as glochids.

Glochids are technically spines but they’re much smaller than the usual spines and can even be smaller than 0.5 cm. They can be difficult to see with the naked eye sometimes.

Because of this, it’s much more difficult to look for any loose glochids than it is to look for spines. Extracting glochids from the skin can be incredibly challenging and can even lead to a type of dermatitis, which I will be discussing later on.

2. Glochids Detach More Easily Than Spines

Cactus spines are firmly attached to the plant and do not fall off while glochids are easily dislodged from cacti. Glochids further help protect the cactus from predators.

Spines don’t detach as easily as glochids do. You can even lift a cactus and its pot a centimeter or two off the ground just by holding it by a spine.

Unlike spines, however, glochids have an unfortunate habit of coming off easily. Even the slightest nudge can prompt it to drop off the cactus.

These glochids help act as a secondary defense mechanism. Wild jackrabbits in California are known to attack almost every plant it finds, except for cacti with glochids, so you can tell just how effective these painful hairs are!

Due to how small and fine glochids are, it’s easier for cacti to regenerate lost glochids than it is for them to grow back new spines.

Read more about this in: Do Cactus Spines Grow Back? [Tested With Timelapse]

3. Glochids are Not as Common as Spines

Glochids are typically only found on cholla and Opuntia cacti, while spines can be found on almost every other cacti species.

Spines grow on almost all species of cacti, except for spineless varieties and Pereskia cacti.

Glochids, on the other hand, are different. These fine, hair-like spines are typically only found on Opuntia and cholla cacti.

It might not sound like much, but these two species are known to be some of the most painful cacti because of these glochids!

Glochids typically grow with microscopic barbs and tend to embed themselves deeper than the typical spine.

So if you plan to purchase any Opuntia cacti like the classic Bunny Ear’s variety, keep in mind that it comes with glochids.

Do Cactus Spines Fall Out Naturally?

Cacti spines do not naturally fall out and will only come off when they are bumped or broken. Cactus spines do not dislodge easily and stay attached to the plant for years.

Cacti have slow growth rates compared to other plants. While most other plants and trees drop leaves annually to replace them, many members of the cacti family do not.

Much of their skin and stems are kept and used for a lifetime. Even the act of producing flowers can take up precious nutrients.

To avoid losing much-needed plant nutrients, cacti do not usually shed their spines. There are cases where the spines may break off but they typically stay firmly attached for years, sometimes even in death.

Nature's fortress: How cacti keep water in and predators out - Lucas C. Majure

Cactus spines have various functions that are all important to their survival, so it’s very uncommon for cacti to drop spines without a proper reason.

Read more in our article on: Why Do Cacti Have Spines Instead of Leaves?

Do Spines and Glochids Come Out of the Skin on Their Own?

Broken cacti spines can eventually be pushed out of the skin over time. Cactus hair, or glochids, however, do not usually come out. Glochids in the skin can cause cactus dermatitis, leaving reddened lesions on the skin for months.

One of the disadvantages of collecting cacti is that you’re more likely to be punctured by your own plants than the casual plant owner. My hands and fingers can attest to this.

There are times, however, when it might be impossible to take cactus spines out of the skin. Not only are they sharp, but cactus spines and glochids can sometimes break into smaller fragments inside the skin.

Broken spines may eventually come out. Glochids left in the skin, however, rarely come out on their own which could lead to cactus dermatitis. This will cover the affected area with red and painful lesions that can persist for months on end.

These spines and glochids may be tiny but they can cause serious pain. If you’ve accidentally brushed against some glochids or spines, it’s best to remove them ASAP and seek medical help, rather than hope they’ll come out on their own!

FAQs

Do cactus spines grow back?

Cacti cannot regenerate lost or damaged spines. Over time, however, the cactus will generate new spines on the same areole. It can take 1–2 weeks for a new spine to grow and depending on the species.

If you remove cactus spines, will they grow back?

Cactus spines that are pulled out or manually removed will not regrow but will be replaced with new spines. These new spines will be softer than the previous growth but will eventually harden as they mature.

Summary of Why Do Cactus Spines Fall Out

Cacti do not naturally shed their spines. However, there are some instances where the spines may be damaged and fall out during repotting or when fake flowers are removed.

It is more common for glochids or fine cactus hairs to fall off cacti, especially with direct contact. This is because they are not as firmly attached to cacti stems as regular spines. Glochids are much smaller than spines and can easily fall off cacti upon direct contact.

Sources

• “Cacti: Biology and Uses” by Park S. Nobel in University of California
• “A Cactus Odyssey: Journeys In The Wilds Of Bolivia, Peru, And Argentina” by James D. Mauseth, Roberto Kiesling, and Carlos Ostolaza in University of Texas
• “Cactus Spine Wounds: A Case Report and Short Review of the Literature ” by Raymond A Dieter Jr, Lisa R Whitehouse, and Rebecca Gulliver in National Center for Biotechnology Information