It is always heart-breaking to see a plant die. Succulents can rot for many reasons and while some can be saved others will almost definitely die once the rot has set in.
Below I will try and answer all the questions surrounding root rot in succulents based on my experience of growing large numbers of succulents commercially for the past 10 years.
Why is my succulent rotting?
Succulents can rot for a number of reasons. The most common are:
Sun-loving succulents grown indoors
Sun-loving succulents grown in too much shade
Using soil from the garden/wrong potting mix in pots
Too much water
Exposure to extreme temperatures
A wound in the wrong spot
One or combination of the above can tip some succulents over the edge but let’s break it down one by one.
Sun loving succulents grown indoors
This, in my opinion (based on feedback from customer and my own experience), is the number one reason succulents rot. Our nursery sells succulents online and at markets and we talk to customers about their succulent adventures frequently.
Unfortunately, often all succulents are marketed as indoor plants, but this is just not the case. Only a small number of succulents can successfully grow indoors.
So if you have a succulent indoors that is stretching from the middle towards the closest window one of two things are likely to happen. It will either loose its leaves, shrivel and die or it will rot and die unless it is placed outdoors.
Most succulents like lots of air and some direct sunlight. Sun through the window for a couple of hours does not seem to be enough for the majority of succulents. They just like to be outdoors.
Sun loving succulents grown in too much shade
While some sun lovers will be ok in the shade but they will grow leggy and pale. Others can easily rot, especially if it is rainy and humid as the water will linger on their foliage longer in a shaded area.
Using soil from the garden/wrong potting mix
I have seen many people potting succulents in dirt from the garden. While succulents will happily grow in just garden soil if they are planted in the ground as they can spread their roots far and white in search of nutrients, they are unlikely to look fantastic in pots filled with dirt.
Potted succulents only have limited space and so to grow well they need top notch potting mix, not heavy garden dirt. A lot of succulents would just about survive but more touchy varieties can easily rot as dirt is not very well draining and can stay saturated for long periods if it rains a lot.
Same applies if the wrong potting mix is used. Some mixes are heavy on the manure and nitrogen which is not that great for succulents. There are quite a few species that can split leaves simply because of too much nitrogen. And then there are potting mixes with incredible amount of sand- this is can rot succulents as sand retains lots of water and gets heavy when wet.
Succulent potting mix is the best choice for plants that will live in pots. In the garden succulents can be planted straight in dirt.
Too much water
We’ve all heard this before. Do not water your succulents too much. While this is partly true, with good quality potting mix and the right position (outdoors for sun-lovers), water should not be that much of a big deal. However, for some succulent species even a couple of days of heavy rain can see them rotted.
These are usually hybrid Echeveria like Romeo that have been created by cross breeding or selectively bred from mutated offsets.
The best thing to do to prevent your succulents dying from too much water is to know a little bit about your plants and research the names. Not always, but most of the time the very expensive plants are also very touchy and so if you don’t have a covered greenhouse or are new to succulents do not get these.
A good rule with watering succulents is to let the potting mix dry out between waterings. Succulents out in the rain should always be planted in pots with holes and well draining potting mix.
Succulents planted in the ground are less fussy and usually only need to be watered in period of drought or in summer during heatwaves. Also, it is best to plant succulents on a slope so they don’t sit in water when it rains heavily.
High humidity along with heat can be a real killer for some succulent species. To avoid rot setting in keep succulents dry when it is expected to be humid and hot. It will also help if they are out of full sun in the afternoon.
Exposure To Extreme Temperatures
Extreme heat and frost can rot and kill succulents. Just like we would get sunburn or frostbite if we stood naked in these conditions for too long, so do succulents- having said that, succulents are much tougher than humans.
On hot days over 35C/95F some succulents exposed to full sun can easily burn/cook, especially if they are in dark coloured pots. Keep potted succulents in shade during extreme heat.
Most succulents are also not frost tolerant. Once the water in them freezes, they will turn all mushy. In cold climates it is best to bring succulents inside when frost is expected.
A wound in the wrong spot
For years I thought the Bishops Cap cactus is super sensitive to water and humidity, no matter how dry I'd keep it. Whenever I got one, it would end up all rooted within a couple of months.
But then one day I found a slug munching away at the base of it, almost making a hollow cave. Lo and behold, it rotted a about a week after. I got a few more and every time the same thing happened- a slug made a hole in the base and somehow managed to collapse the of the cactus!
Some succulents attract pests far more than others and a wound in the wrong the spot will trigger rotting.
Another example is a caterpillar eating the middle of an Echeveria Ebony. The plants stalk & roots completely rotted and all the leaves fell off.
There is very little that can be done about this as pests will always find a way to come and dine on your succulents. To get a plant rotting from a pest attack is not that common though, but it definitely happens.
What does root rot look like in succulents?
Root rot can manifest itself in different ways for different succulents. Some can have black roots that are not squishy and mushy, but are rotting the rest of the plant all the same. Some will have very watery roots that will turn to mush when touched. And then some will have roots that appear ok, but the stem leading to the roots is going black.
How do I know if my succulent is rotting?
It can be difficult to identify root rot until its too late. Most of the time rotting succulents will have one or more of the following symptoms:
Rotting/ mushy leaves
Many succulents will naturally loose a few leaves throughout their life and sometimes these leaves will rot away without damaging the rest of the plant. This usually happens after rain, hot days or when a succulent is re-potted and bottom leaves are touching the potting mix. But in other instances, this can be a sign of the succulent suffering from rot.
Even a blackening stem may not always be rot, but simply a wound from some kind of a pest attack.
Mushy roots are definitely a sign of a rot, but then I’ve seen plants that just grow new roots and grow without any adverse effects.
It is only after a few of these signs happen simultaneously, that rot is properly noticed and definitely means the whole plant is affected and dying.
Can succulents recover from root rot?
Yes and no. It all depends on when the rot is discovered and how far into the plant it has spread. Once the stem is going black, the leaves are falling off and the center is black too, there is no going back and the plant will die. If the rot is caught early and only the very bottom of the stem has started to rot, the top part of the succulent can be cut off and re-planted.
Only once the stem is cut will it become apparent how far into the plant to rot has gone. If the inner circle of the stem is black, then that is rot. If it has spread to the top of the plant, it is likely it won’t be saved.
As I’ve said above, some plants fix themselves and will drop the rotted roots in favour of new ones. I’ve even seen plants that only half rot and then grow lots of new offsets. And I’ve also seen plants that go from looking gorgeous one day to mush the next (this usually happens after extreme weather of rain, high humidity and extreme temperatures).
How do you fix rotting succulents?
If the rot has not yet spread to the whole plant, all the way to the top, the best way is to cut the healthy parts off and replant as cuttings. Succulents that have the ability to spread from leaves can also have the healthy leaves, not yet affected by rot, taken off and left to grow a new plant. Once the rot has spread through the plant, there is no fixing it.
In conclusion, rot in succulents can happen due to a number of things. Sometimes the plants can be saved, but if the rot has set in and spread throughout the plant, there is little chance of saving it.