Maybe you looked over at your cactus and saw the spines falling off the plant. With the needles of the cactus being the defining trait of a cactus, that makes it a big deal.
Do cactus spines grow back? No, cactus spines won’t regrow after removed. Cacti can grow spines at other parts of the plant in newly grown areas, but they won’t grow again where the spines were removed. This is permanent, so you want to take care not to lose spines.
If you’d like to learn more on how cacti lose their spines and how to stop it from happening, keep reading because we will cover this in depth.
How Do Cacti Lose Their Spines?
Your cactus could be losing its spines for several reasons like:
- Lack of fertilization
- Nutrient deficiencies
- Touching the cactus
Cacti will lose their spines for a number of reasons, but this highlights some of the key reasons that they lose their spines. In knowing this, you can take action to stop the cactus from losing its spines based on the cause. Prevention is better than the cure, especially because you can’t return the spines to their normal state. Once the spines get removed, it’s permanent.
Understanding the Cactus Spines
To better understand why cactus spines won’t grow back after you have lost them, let’s have a look at the spines. They act as a type of leaf, but they do this for the cactus. Cactus spines serve the following purposes:
- Collect water vapor at night
- Hold in an insulation layer of air
- Provides shade against the sun
- Water regulation
A cactus without spines will have an increased risk of water loss because the spines provide you with an extra layer of air protection.
Cactus plants that have had the spines damaged in an area won’t regrow in that part. This leaves them susceptible to a number of problems like predators eating the plant, sunburn in that portion of the cactus and less water regulation.
If you have ever noticed when watering a cactus, the spines can change colors. In fact, I wrote about that here in my article, “Why are My Cactus Spines Turning Red?”
Development in New Areoles
Cactus spines that have broken off on a plant won’t regrow in that spot, but they can develop on new areoles. Areoles are light-colored bumps from which the cactus spines will grow out of. In some cases, the cactus will grow new spines in an areole still active. You don’t, however, tend to see this with older parts of the cactus.
You don’t want to remove the aeroles because the spines won’t grow back if this gets removed.
Because of how the spines play such an essential role to the cactus, it will make every effort possible to bring the spines back. In cases, where the damage was too great, the spines won’t regrow.
What Do You Do When the Spines Won’t Regrow?
In some cases, the spines don’t return: What do you do? First, identify the reason why the spines have fallen off. The answer could be as simple as a cat that likes to rub up against the cactus. Believe it or not, the cactus needles break off easily. You have to exercise caution. Even touching the cactus with your hand can break off the spines, and they won’t regrow after they have broken off.
Prevention is the only way to respond to this. Once the needles have fallen off, consider it too late. If the plant has mealybugs, a common reason for cactus plants losing their spines, you have to respond fast.
To kill mealybugs, you will take a solution of 75-percent rubbing alcohol and 25-percent soap mixture.
Important to note: This will kill the existing mealybugs, but it will do nothing to stop future outbreaks. Beware of overwatering or overfertilizing your cactus because this can attract mealybugs.
Mealybugs can sneak up on a person, and they will suck the juices right out of the cactus until it dies. For that reason, you should check your cactus occasionally for an infestation. You can also use Apple Cider Vinegar to stop the molting process of mealybugs and killing them. This has the advantage in that it doesn’t use harmful chemicals that will hurt your plant.
What Do You Do if Your Cactus Lost Its Spines?
We have covered why the cactus loses its spines and how the cactus won’t grow back spines. What do you do after the fact that a cactus lost its spines? On a healthy cactus where it continues to grow, don’t do anything. You can’t do anything.
Instead, let the cactus grow until the portion with the loss of spines look much smaller than the rest of the cactus. Identify the cause of the damage to keep your cactus from further losing its spines.
In cases where extensive damage removed the spines from your cactus, you can try to keep it, but the loss of its spines will make it vulnerable to many things. To worsen the problem, the spines will never return, which will always leave it vulnerable. Prepare for the possibility that the cactus will die.
You have one situation where someone’s so-called friends skinned the spines off his cactus intentionally. Let’s just say, that isn’t a friend. Get new friends. Unfortunately, the cactus won’t survive in most cases, and if it does, it will survive as a shadow of its former glory. The only thing that you can do is to move it indoors and protect it from damage, but even this may not keep it alive.
In cases where the damage was extensive, the best thing that you can do is to start over by buying a new cactus.
Now, if you feel curious about the color of your cactus spines, check out my article, “What Color Should My Cactus Spines Be?”
What Can You Heal with a Cactus?
While spines won’t grow back on a cactus, you do have other things more forgiving. This plant knows how to deal with harsh conditions. For example, you can heal damaged roots and broken plant stems in most cases. You could also restart the cactus. Once a cactus loses its spines, however, it loses the crucial thing that makes it identifiable.
Think of cactus spines as like an adult tooth. Once you lose them, they don’t come back. The damaged part will eventually move closer to the bottom of the plant as it grows. New growth will have good spines that protect it.
Certain Cactus Species That Can Possibly Regrow Spines
We say that cactuses won’t regrow their spines because, generally speaking, they won’t, but you do have some cactus species that some cactus lovers say can regrow their spines. You might choose some of these cactuses if you were a beginner who wanted a choice that can handle more harsh conditions.
Some of the species that some believe will regrow spines in certain cases include:
- Trichocereus pasacana
- Mammillarias — Usually won’t regrow a spine cluster
This may depend on the age of the cactus as well with some species more likely to regenerate the spines after damage.
How Do Cacti Grow Spines?
To fully understand why a cactus generally won’t regrow its spines, let’s have a look at how the cactus grows its spines. The spines on a cactus serve the same function as the leaves of a tree or plant, but the cactus should never shed its needles because they never grow back for most cactus species.
The spines grow from the inside of the cactus tissues, rather than the skin, which explains why they don’t grow back. Most of the spine growth comes from the inside of the areoles. Areoles perform one of the most important roles for the plant. In some cases, they give rise to flowers, but they serve the chief function of growing multiple spines. Usually, areoles will grow 10 or more spines in a single cluster.
Cactus spines usually won’t regrow, which is why you must pinpoint the cause and correct it as soon as possible. Provided the damage wasn’t extensive, your cactus will recover in most cases, but it does leave it vulnerable. In some cases, buying a cactus online and having it shipped to your home can cause damage to the spines from it bumping around. Damage can come from something as simple as that.
If you found this article interesting, maybe you will like the article, “Is My Cactus Growing?”