Succulents are quite hardy plants. These plants don’t require that much attention, making them one of the easiest plants to grow. But similar to other plants they are vulnerable to pests and diseases.
Black spots on succulents are one of the most common diseases among these plants. However, chances are you’ll be able to save your plants if you catch the disease at its early stage.
But it’s not that easy to catch the early symptoms of this disease.
That’s why we decided to write a complete guide on this matter. In this well-crafted article, you’ll know everything from the reasons for black spots on plants to how you can prevent it.
Let’s get started-
Causes for Black Spots & How to Cure These?
Black spots on succulents are mainly caused by 5 reasons. These are fungal infection, sunburn, pests, frost, and overwatering. But it’s not that easy to identify which black spots are caused by what reasons.
Nonetheless, we’ve tried our best to come up with the most relevant photos and descriptions for each of the reasons.
Cause 1 of 5: Water Warts, Fungus, and Rot
If you live in a humid and warm area, you’ll most likely see water warts, rot, and fungus infection in your succulents. You see, most succulents are from dry areas. So, these plants absolutely hate humidity.
Reasons of Water Warts, Fungus, and Rot
It doesn’t matter if you don’t water your plants or keep them in the dark. No matter what you do they’ll get a fungal infection if there’s a lot of moisture in the air.
Fungus and water warts form black round spots that can grow at a rapid speed. Before you know it, you’ll find out that the entire leaf is colonized with round black spots. Most of the time the leaf will fall off after it’s completely rotten.
Source: Succulent Growing Tips
Although, some succulents are more vulnerable to fungus than others. Echeverias, Pachyphytums, Graptopetalums, Pachyverias, and Graptoverias tend to have more fungus problems.
In fact, these plants can get a fungal infection only after a few days. Although you can slow it down by placing a cover above them.
Cure for Water Warts, Fungus, and Rot
In humid seasons, you should apply a fungicide on the affected plants every other week. It can be an organic fungicide or a chemical fungicide. Although, it’s better if you use an organic one.
Here are some of both organic and chemical kinds of fungicides that you can consider-
If you’re in a high humidity area it’s better to limit water for your plants. However, some plants won’t be able to take the stress.
That’s why water your succulents once a week to prevent shriveled leaves. Although keep in mind that you should never spray water on the leaves.
You see, succulents can’t absorb water through their leaves so you won’t be doing them any favors. The best practice is to pour water around the root for sensitive succulents.
Another thing to keep in mind is, make sure to use a succulent potting mix or any other mix that drains well. The heavy potting mix tends to hold water, making the fungal infection worse.
Just in case you need, here are some of our favorite succulent potting mix-
- Superfly Bonsai Succulent & Cactus Soil Mix
- Organic Succulent and Cactus Soil Mix from The Next Gardener
- Bonsai Jack Succulent and Cactus Soil
- Fat Plants San Diego Premium Organic Cacti and Succulent Soil
However, if you see that the plant is rotting and the leaves, stem, and root turning into a black shade, then there isn’t much hope.
The only thing you can do at this point is the top of the plant and plant it as a cutting. But remember that you can only do it if the rot hasn’t extended to the top.
Lastly, we have to say rot isn’t that easy to detect. Sometimes the plant will show some black spots. Sometimes it’ll suddenly collapse, leaving you with nothing to do.
Cause 2 of 5: Sunburn
Sunburn is a concerning problem for succulents. Some succulents have a higher tolerance to sunlight but most of them suffer some kind of damage when it’s over 104 degrees Fahrenheit.
Reasons of Sunburn
Let us explain how this works. You have to keep in mind that weather forecast temperatures are basically shade temperatures. So, if you put a thermometer outside for 1 hour it will show much more than the weather forecast.
So, now you get an idea about how much heat plants have to deal with. That’s why even strong plants such as succulents aren’t immune to sunburn. An average human would have to go to the hospital if he spends so much time in such scorching heat.
If you’re in an area where the temperature exceeds 40 degrees Celsius, your succulents are most likely going to get sunburns.
Source: Succulent Growing Tips
Although the situation changes when the plants are in the ground. Roots can maintain a cool temperature when they’re in the ground than in pots.
However, different succulents show different symptoms when exposed to hot sunlight. Many of them have their leaves fall off, many plants collapse out of nowhere. But mostly these plants get black spots or marks.
The worst part is, the marks or spots don’t disappear. The plant has to grow out of the spots itself. Sometimes this process can take a long time.
Cure for Sunburn
It’s possible to save a sunburnt succulent. First of all, you have to remove the burnt leaves from the plant. Yes, we know it doesn’t feel good to take out the leaves but those leaves won’t heal. So, it’s for your plant’s own good.
Now, you have to give your plant a chance to adjust to the sunlight. For doing this, limit the daily sun time to 3 to 4 hours and make sure to arrange it in the morning. After a few days, increase the sun time by 1 or 2 hours a day.
Although, don’t forget to bring the plant to your house after sunset. You can also buy a sunblock shade cloth or a sunblock garden netting mesh for protecting plants from sunlight. This way you don’t even have to bring it inside.
Cause 3 of 5: Pests
Pests can be a very irritating thing for you when you have succulents. There are different kinds of pests such as aphids, mealybugs, ants, and snails. Let’s go through them one by one.
Reasons of Pests
Tiny aphids to big slugs, snails, grasshoppers, and caterpillars all of them feed on succulents. Even big animals such as birds, mice, and kangaroos eat these too.
While the big animals take a huge chunk, the small insects and bugs leave small marks. These small marks on the foliage slowly turn into a darker color and end up as black spots.
The worst part is, these black spots won’t go away until the plant grows out of it.
Source: Juicy Kits
You see, aphids and mealybugs secrete a sticky fluid that sticks to the plant, making it look worse. Moreover, these things hide in the new leaves. As the new leaves can’t grow out of it, sometimes they die.
While we’re on the subject, we have to mention ants. The thing is, ants thrive on the fluid aphids and mealybugs make. They somewhat spread and farm these things for their own reasons. Moreover, ants tend to protect aphids and mealybugs from different kinds of predators like wasps and ladybugs.
Source: Joy Us Garden
Lastly, there are slugs and snails. These things make tiny holes in the succulent foliage that later turn into a darker black spot. These sneaky little things hide behind walls, pots, and rocks. It’s even harder to catch them as they only come out at night.
Cure for Pests
If you have succulents, then you’re most likely going to face pests and bugs at some point. These things spread quite fast and it’s not something you’ll be able to catch.
Aphids and bugs repopulate so quickly that if you delay 1 or 2 days, it means hundreds and if not thousands of these things are waiting to be born and devour your plants.
The good news is, you can kill aphids quite easily with pyrethrum based sprays. These things are usually green, black, brown, and sometimes orange.
If the numbers aren’t too high, you can kill them with a toothpick and wash off the plant. Then, separate the plants from the others so that it doesn’t spread and infect your whole garden.
However, you have to use pesticides for huge infestations. But you need to keep one thing in mind. Pesticides can kill a lot of good insects too. As these good insects are suffering in a world full of pesticides, you need to do what you can.
That’s why you should use the pesticide at night when the good insects aren’t flying. Something as small as this can be a step forward. We would have a tough time growing our harvest without these beneficial insects.
Although you can try using neem oil spray on the infected plants after isolating it. But it’s not that effective as many aphids can survive it quite easily.
Mealybugs are tough pests resistant to pesticides. You see, mealybugs have a wooly cover that protects them from pesticides and such.
Moreover, they are kind of masters when it comes to hiding. They can hide in the unexpected and narrowest places like between stem and leaves, nested in dried up leaves, under pots, tables. They can even hide in debris around the plant.
They can lay anywhere between 300 to 600 eggs keeping out of sight. Obviously, they lay the eggs near the plants so that the little nymphs don’t have to crawl far when they hatch.
When the bugs are young, they can spread quite far for being able to move fast. So, you’ll find that many of your plants will have bugs in the beginning.
This is why detecting them early and isolating them is the best option. Also, it’s important to keep your pots and the area around it clean.
However, if you somehow find a bug or two you can squash them with a toothpick. Next, pull out the infected leaves and thoroughly check around the plant to see if there are any bugs left.
Now, you have to isolate the infected plant so that it doesn’t infect other plants. After isolating the plant, you need to monitor for a few weeks to see if there are any other outbreaks.
Although if the situation is already bad and there are tons of mealybugs in your garden, you need another approach. In such cases, you have to use 70 percent isopropyl or rubbing alcohol spray.
Note that each and every mealybug needs to be killed and washed. There are many pesticides in the market that claim to kill mealybugs. But in most cases, they’re not that effective. Even worse these products are very toxic to other useful insects and humans.
While 70-percent isopropyl alcohol does the job quite well, it needs multiple applications. Nonetheless, if you have succulents they are going to be vulnerable to mealybugs the option is to regularly check and clean them.
Ants and bugs have a special relationship. But it needs to stop in order to protect your plants. No matter how you see it, ants are a pest.
However, removing ants is harder than it sounds. These little things can always find a way to manifest in your garden. The worst part is, they are quite efficient at it.
You can always use liquid ant killer products but these will only kill the workers. The queen is your main target as she is the one who produces millions of eggs under the ground.
Well, there are a lot of borax and sugar lure recipes that you’ll find online but most people don’t really have any success with those.
So what’s your best option?
You just have to keep your garden clean and kill any ants you see with pyrethrum spray.
Snugs and Snails
These sneaky little things make tiny holes in your plants, leaving a black mark behind. So what can you do to remove them?
Well, there is a simple and effective solution.
Put some beer on the ground. You can put it on a tray if you want. After some time the snugs and snails will discover it and drink it until they die.
Cause 4 of 5: Frost
Frost is quite similar to sunburn in terms of symptoms. Dark spots are often seen on the foliage when frost attacks. Sometimes, if the plant is badly suffered, it can collapse on the ground.
Reasons of Frost
If you don’t live in an area where the temperature gets below 0 degrees Celsius, then you don’t have to worry about frost. Using a frost cloth is enough for protecting your plants.
Source: National Gardening Association
Cure for Frost
If you see frost attack on your plants, it means that you’re a little late. However, you can still salvage the plant. Simply remove the affected leaves and you’ll be good to go.
If the black spots have reached near the top, cut the top of the plant and put it in a pot as a cutting.
Although you can always use a frost cloth over your plants to protect them from mild frosts. But remember that only a handful of succulents are resistant to frosts such as the Sempervivums.
So, if you’re in an area where the temperature gets below 32 degrees Fahrenheit and snow settles for days, then the frost won’t be any good.
In such cases, you need to bring the plant indoors and wait until the temperature gets normal.
Cause 5 of 5: Overwatering
If you notice that your plants are getting all mushy and have black spots, it usually means one thing. Your plants are drowning because of overwatering.
Reasons of Overwatering
You see, the leaves, stems, and roots of succulents have a special ability. They can store water for surviving in extreme weather conditions. So, when you overwater you’re basically overfilling your succulent’s water deposit causing it to bloat and burst.
Finally, the blacks spots appear when a fungus develops in the injured plant tissue.
Cure for Overwatering
Chances are you won’t be able to save your plant when it’s overwatered.
However, there are a few things to check before you uproot the plant. First, remove the plant from its pot and see if the roots are still healthy.
If the roots are still fine, you need to trim the damaged stems and leaves. Then plant in dry soil. But remember to go easy on the watering this time.
Now if the roots are all mushy, it means that they’re dead and there is nothing you can do. You can salvage any remaining healthy parts but you’ll have to throw away the rest of the plant. Then, put the remaining healthy parts as a new plant.
Lastly, remember to throw away both the mother plant and the soil it was planted in. Because chances are they’re both contaminated with the fungus.
How to Prevent Black Spots on Succulents?
We all know the phrase, prevention is better than cure. When it comes to plants this is even more important. You see, sometimes you won’t find a cure when it comes to blacks spots on succulents.
For this reason, we’ve figured out some preventive measures for you. If you follow these, chances are you won’t ever have to face problems related to black spots.
Keep Them On Inspection
A regular check can be a very useful measure for preventing any kind of disease. So, always check the conditions of your plants. You can do it while you water your plants. It’ll let you detect any early symptoms of pests and diseases.
The thing about black spots is, it’s always better to treat them early before it can do any serious damage to your plants or your entire garden.
However, if you somehow notice an early sign of disease, don’t assume that it hasn’t spread to other plants in your garden. Pests and diseases can spread very quickly and efficiently.
Moreover, as we’ve mentioned earlier, ants protect mealybugs and wasps, helping them to spread to other plants. So, when you see a sign on one of your plants, make sure to check them all.
Furthermore, check how well your plants are growing individually. Poor growth can indicate a lot of things. It can be a result of overwatering, fungal infection, or pests. That’s why you should always check all of your plants thoroughly.
Quarantine and Re-pot
When you buy a new plant, it’s better to keep them separate from the rest of your plants at least for 2 to 3 weeks. This way you’ll get to know if the new plant has any diseases regarding black spots.
Moreover, if the plant has pests it’ll provide them time to hatch. Then you can deal with the pests in the proper way.
A lot of gardeners re-pot their newly bought plants with their preferred growing medium. This can be a good thing for you. When you re-pot the plants you’ll get to see the condition of roots and check if there are any root mealybugs.
While many people may see this as overdoing, it’s actually good for your plants if we’re being honest. You see, when people re-pot their plants, they treat it with insecticide. Undoubtedly, this helps to prevent any pests and diseases from entering the plant.
Finally, if you want to be extra sure, you can re-pot the plant with a sterilized potting mix. This will be an extra step in killing any remaining insects or eggs.
Cleanliness in your garden is one of the most important measures in preventing pests and diseases. Never leave any dead leaves or flowers. You should try to remove these things whenever you can.
However, some growers have a tendency of removing flower stalks of plants such as Adromischus before they can flower. They do this to drip the nectar on the plants. But the problem is this can cause molds.
And the worst part is, wet and dead plant material is the perfect breeding place for fungi.
So, whenever you work on your garden, remember to clean up the debris that’s left behind. Moreover, you can use a disinfectant solution to keep away any pests and diseases.
Even though disinfectant solutions are always better, you can use 70% isopropyl alcohol if you want.
So, that’s all we had to say about black spots on succulents. We hope this article helped to answer all of your questions regarding this matter.
Before wrapping up, we have a piece of advice for you. Always take better care of your plants. A little caring can go a long way.