White spots on a pencil cactus
Generally speaking, a Pencil Cactus (Euphorbia tirucalli) is easy to grow. You just place it in some sunny spot in your garden, in an arid soil, or a soil you got in a store for your succulents, and you can almost forget it. Or you can enjoy the beauty of the plant… Growing pencil cactus indoors, the most common problem people experience (or a most common mistake they make to say it more precisely) is over-watering, which leads to yellowing of the cactus. A much less common problem are irregular white spots of a pencil cactus, and we will look at the issue right now.
Before diving into details, let me briefly summarize the three main causes of white spots on a pencil cactus: Pests, especially mealybugs are the no. 1 reason. The second reason is mechanical damage, which can be caused by hail, storms, or even your beloved cat mistaking the cactus for a toy :). The last reason is lack of certain nutrients in the soil. Many people grow pencil cactus all around the world, and it is important to know what to do when you see the dreaded white spots. Let’s have a look at it.
Mealybugs or other pests as no. 1 reason for white spots on a pencil cactus
Pencil cactus isn’t one of the succulents that attracts a lot of pests, but in some cases it does attract them, or they may jump over to it from another infested plant you have at home. Many of these insects are super small, and unless you have very good eyes you won’t spot them without a magnifying glass. Some pests also hide during the day, and crawl out of their holes only during the night (when they feast on the cactus), and hence you again may struggle to spot them. Anyway, get a magnifying glass and inspect your cactus in different times of a day. If you notice any movements and small bugs, you have found your culprit.
What works best against bugs are either chemical pesticides from a shop (I strongly suggest you against using them though, especially on indoor cacti, since the last thing you want is to spraying such substances at your home), or homemade solutions, such as 90% alcohol, or combination of vinegar and water. There are many variations, just google it and you will find the recipe. What I want to emphasize though is that you will typically have to repeat the procedure a couple of times, and it can also happen that some bugs will survive, or their offspring will (in the form of eggs and larvae), and you’ll have to repeat the procedure all over again.
For this reason, you should think whether it wouldn’t be wiser throwing the infested pencil cactus away, together with the soil. Doing so you prevent the infestation of other plants (if they aren’t infested already), and can get rid of the bugs once and (hopefully) for good.
Mechanical damage as the no. 2 reason of white spots on a pencil cactus
If you grow your pencil cactus outside, you never know what the nature will throw at it in our era of climate change. Strong storms are ever more common, and hail may fall from the sky in almost any period of the year. Particles of hail, or even other sharp particles carried by strong wind, can easily damage your pencil cactus. Such a mechanical damage of tissues can often manifest in a form of white spots on the cactus, in the points of impact.
Other thing many people underestimate is what their cats (or other pets) can do to the plants. Cats are curious animals, and they enjoy exploring their surroundings. Pencil cactus is a funny looking plant for them, and they may start playing with it. What’s an innocent play for a cat, however, can end up deadly (or art least highly damaging) for the pencil cactus. Tissues cut with cat’s paw can easily open up and manifest as white spots on the cactus. Consider this especially if you have a cat at home (or your neighbor has one), and it has access to the plants.
Lack (or excess) of certain nutrients in the soil as the no. 3 reason for white spots on a pencil cactus
We can find many resemblances between the kingdom of plants and the kingdom of animals. For example, when we people lack Zinc or Calcium, we will have white spots on our nails. And though our organism is much more complex than the one of a pencil cactus (or any other plant for that regard), succulents also need some nutrients. If they lack some or get excess of some (for example when you over-fertilize them), they may change color, or develop white spots.
If you ruled out pests and mechanical damage, think about this one. Haven’t you fertilized the plant recently? Or haven’t you planted it in a soil intended for garden vegetables (or other type of plants), instead of soil for succulents? If you made any such changes, it can be that the pencil cactus experiences lack of some nutrients, or, on the contrary, it gets more than it needs. As a result it may develop white spots. Addressing this cause isn’t hard though. Just repot the plant to a fresh succulent soil, or stop fertilizing for some time (or completely, since pencil cactus doesn’t really need it and you are just throwing money away).
Conclusion
White spots aren’t natural for pencil cactus. As soon as you spot them, you should investigate your plant (and your actions related to it), trying to find the cause. Pests like mealybugs are the most common reason, but when you rule them out, you should consider mechanical damage, or lack/excess of certain nutrients in the soil. I hope this post helped you understand the issue, and you will soon see your pencil cactus in full beauty again 🙂
Pencil cactus turning red
Pencil Cactus (Euphorbia tirucalli) is often nicknamed Sticks on Fire. If you ever wondered why, you can now see the answer in your own backyard :). This wonderful succulent native to semi-arid tropical areas has a tendency to turn red in certain conditions, and in this post I will try to explain when it happens, why, and whether you should worry.
Let me start with good news: It is completely natural for a pencil cactus to turn read, in the main growing season, when it has access to plenty of hours of direct sunshine. We can see this more often outside, when we grow the cactus in the garden on a sunny spot (not in a shade of a bigger bush or tree). However, it isn’t completely unheard of seeing this with indoors Pencil Cactus as well, especially when you place it on a windowsill, and your room is oriented to the south, getting as much sunshine as possible. If you ever spot pencil cactus in its natural habitat (for example when traveling), you will notice that almost all plants turn red (setting their “sticks on fire”) in summer.
You should not worry if your pencil cactus never turns red
Whether or not your plant will turn red does not depend only on the amount of sunshine it gets. It also depends on the climate, how strong the sun is, how many hours a day it shines, how often it is cloudy in your area, and so on. What I try to say here is that in many instances you may never witness your pencil cactus turning red. It doesn’t mean that you do something wrong, or should change something in a way you treat the plant. It is just that the conditions aren’t fitting for the reaction within the plant that produces the red color.
In fact, the red color is a result of stress reaction of the plant. It releases certain molecules trying to protect itself from extreme sunshine (no need to elaborate on the chemistry here since this is a blog and not a scientific paper), and the presence of these substances changes the color of the leaves to red. Once the hot season ends and the cactus gets less sunshine, the substances will slowly wash away from the plant, and it will get green again.
Indoor Pencil Cactus turning red can be a result of some serious issue
If you grow your Pencil cactus indoors, and in a spot where it isn’t exposed to plenty of hours of sunshine every day, red color can be a reason to worry. Your plant suggests you that it experiences some stress again, but this time the excessive sun isn’t to blame. The most common problem people experience with Pencil Cactus indoors is over-watering, but in such a case your cactus will turn yellow, and not red. Hence we should rule it out. If over-watering isn’t the problem, what is?
It can be many things, but I would rule out under-watering either, since it is almost impossible to under-water a pencil cactus. Hence the most common issues you should look for are:
- Extreme changes of temperature during the day. This can happen in certain scenarios, such as when you heat the room only when you are at home and it gets cold when you are away, at work for example.
- Over-fertilization. Pencil cactus does not need any fertilization. If you fertilize it often, the excessive nutrient content and change of pH of the soil can cause the cactus an extreme stress, and it may turn red in response.
- Some infestation with pests or fungi. If this is the case, you should typically spot something going on, such as white spots on the cactus, or some insects roaming around.
Remedies for pencil cactus turning red from unnatural reasons
As you can likely guess, each problem from the ones I just mentioned requires a different form of remedy. If you identify extreme temperature changes as a culprit for red color, you should either adjust the patterns of heating/cooling of your room, or move the pencil cactus to another spot of your house, one where temperature does not fluctuate much.
In the case of over-fertilization, I would suggest stopping any fertilization for at least a year, and if you overdid it to some extent, you can also repot the pencil cactus to new soil, the one you get in a shop for your cacti and succulents, so it again resides in a soil with optimal conditions for the plant.
Infestation are fungi are the hardest to address, and in many cases the best thing you can do is throwing the cactus away, together with the soil, making sure other plants in the house won’t catch the infection. I understand though the you may have a special attachment to the plant. Maybe you got it from someone you love, or someone who has already departed this world. And you want to save it at all costs. In such a case, it makes sense investigating the issue further, and trying to cure the cactus from the pests. But such information exceeds the purpose of this blog post, and you’ll have to look elsewhere.
Conclusion
It is completely natural for a pencil cactus to turn red in the summer, as long as you grow it outdoors in some warm area which gets a lot of sunshine. It is the reason why this plant got a nickname “Sticks on Fire“. You should not worry–enjoy the spectacle instead!
If your indoors pencil cactus turns red, however, or even an outdoors one in autumn or winter, it can signify some serious issue, and it is a clear sign that the plant is unhappy with something. Investigate the issue following the advice from this post, and address it accordingly, making sure you won’t lose your beloved cactus…
Pencil cactus turning yellow
Pencil Cactus, known also as “Sticks on Fire”, or “Milk Bush” is a unique and interesting succulent that will catch the eye of every visitor of your house. Native to semi-arid tropical climates, it isn’t particularly demanding when it comes to soil quality or some special treatment. Even inexperienced growers can enjoy the captivating beauty of this cactus, that is naturally green indoors, but will turn to beautiful red color in summer season. Turning red is completely normal for this succulent. Turning yellow isn’t though, and in this post we will outline why it happens, and what you can do save your Pencil Cactus.
Before we dive into details, let me briefly summarize the three main reasons why your Pencil Cactus may turn yellow: Over-watering (which causes root-rot) is the no. 1 reason, natural aging no. 2 (these cacti can live decades, but they aren’t immortal), and specific fungal infection no. 3, and the less likely reason. Let’s have a look at all three issues in detail, so you can identify the culprit, and address the yellowing of your favorite cactus.
Over-watering as no. 1 reason of Pencil Cactus (Euphorbia tirucalli) turning yellow
Many people mistakenly think that when a plant turns yellow, it lacks water. This is no doubt true for many plants in the garden, and trees in the forest, but succulents are exception to the rule. Native to semi-arid areas, it is almost impossible under-water this cactus, since it is used to surviving long periods of drought. Plant strength can sometimes become its weakness though. Kept at home, or in a garden, especially outside of its natural habitat, it is very easy to over-water this cactus. The events unfold in the following manner:
- You give your pencil cactus too much water too often, or even not but have it indoors in a pot without a drainage hole. In both cases the soil remains constantly moist or even wet.
- In such a wet soil the roots of your plant will start to rot. This process can be slow, and you may not notice anything for quite a while, thinking that you treat your pencil cactus well enough.
- When the root rot advances, the root system isn’t able anymore to transfer water and nutrients to the body of the plant. It dries from inside, turns yellow, and the cactus will eventually die.
Addressing over-watering in a pencil cactus
Whether or not you can save your pencil cactus depends on the severity of root rot. If it has advanced to some stage and basically all the roots are rotten, you cannot really do anything except of learning a lesson, and do things better with a new succulent. If you spot the problem relatively early, however, you still have a chance to save the plant. Make sure to do the following steps:
- Remove the cactus from the original pot, and clean the roots from all soil.
- Cut away all rotten roots, but leave the parts of the root system that are still healthy on the plant. You should never cut away all roots whatsoever, because plant needs roots to gather nutrients from the soil, and water.
- Plant the pencil cactus in a new pot, in a dry soil, some good potting mix for succulents. You should also use a pot with a drainage hole.
- Water it heavily but just once, and then wait for the soil to completely dry, and just then water again. Don’t forget to always empty the saucer after watering. The key is to make sure that roots take some water, and then they stay in a relatively dry soil, and the rotting won’t continue.
Aging as a no. 2 reason for a pencil cactus yellowing
Some succulents can definitely outlive us. Growing slowly and enjoying their time on this marvelous planet, succulents can sometimes live up to 200 years. Of course it depends on the specie, and also growing conditions and everything, but it is fair enough saying that a plant can accompany you for your lifetime.
Pencil cactus can live for decades, and when it starts turning yellow simply because it is old already, and readying for a transition to the other world, the heaven of plants :), you cannot do much except of congratulating yourself. It isn’t common for us to outlive our succulents, so you likely did a good job with this cactus. What confuses some people is that they bought the pencil cactus just ten years ago and not it turns yellow.
The thing is that you do not necessarily know the age of the plant you are buying. Maybe it was ten or twenty years old when you bought it, they just pruned and shortened it regularly, hence it appeared small and young. Mark my words: if you rule out over-watering, it is highly probable that your pencil cactus has simply aged, and it is time to say goodbye to it.
Rare fungal infections can also be to blame here
Fungal infections and root rot often go hand in hand, but in some cases just the upper part of your plant can be affected. Pencil Cactus isn’t prone to pests and infections, but we should realize that we often grow it in environment that’s far away from its native land. Hence it may come in contact with pests and fungi it isn’t used to, and if the contact happens when the cactus is vulnerable–for example after winter, or after some stress caused by mechanical damage or extreme temperature change, the infection can find its way into the plant.
When you rule out over-watering and aging as reasons for the undesired changes in the color of your cactus, you should consider the option that it got infected with some fungus. This isn’t a likely cause, and it will be responsible for one in a hundred cases, but it is a possibility we cannot simply rule out. And I don’t have good news for you:
In a case of infestation of your pencil cactus, the best thing you can do is to throw it away, together with the soil. You should also disinfect the pot afterwards. The thing is that these fungal infections aren’t easy to treat, and they can jump to other plants in your house, which is likely the last thing you want to witness. That’s why I suggest you to simply get rid of an infected plant, unless it is a super rare and expensive succulent (then it makes sense trying to treat it). Pencil cactus does not fit this category though.
Final thoughts
When your Pencil Cactus (Euphorbia tirucalli) starts turning yellow, it is always a reason to pay closer attention to the plant. This particular color change doesn’t signify anything good. In most cases it is a result of a root rot, in less likely cases your cactus simply aged and will die soon, and in even less likely cases it is infected with some fungus. I hope that after reading this article you can easily identify the cause of the yellowing of your cactus, and will take action accordingly. Thank you for reading, and good luck with your plants!
Matthew
May also interest you: Succulent plants FAQ – All questions and answers you may have about your plants.