The pencil cactus, or Euphorbia tirucalli, is native to semi-arid tropical regions of Asia and Africa, and can grow quite big in its natural habitat. It gets its name from its green, pencil-like branches that grow from the ends of thicker, brown branches. These pencil-like branches can produce small flowers during the spring and summer.
The pencil cactus is a succulent, meaning that it can store water for use during times of drought. This helps it to thrive in the semi-arid conditions of its natural habitat.
Despite its nickname, this plant is not a true cactus, and does not have the spines typical of a cactus. This makes it a safer choice if you want a houseplant but also have children or pets.
And, while the pencil cactus may not have as many problems as certain other plants, it does have its fair share of issues that may cause concern for its owners.
One of the most common problems encountered by pencil cactus growers is when the plant begins to shrivel. This means that there is an environmental factor affecting the plant and causing it stress.
The most common causes of a shriveled pencil cactus are too much water, not enough water, and not using the right type of soil.
In this article, we will discuss the different causes of a shriveling pencil cactus and how to resolve each one. So, if you are currently experiencing this problem and wish to learn more, just keep reading.
Why is my pencil cactus shriveling?
Too much water
Pencil cacti, like most succulents, are capable of storing large volumes of water for future use. However, if your plant attempts to store an excessive amount of water, it will become too heavy and strained to support itself. It may then start to droop and its foliage may shrivel.
With other types of houseplants, these signs can sometimes point to underwatering, but if your pencil cactus is yellow or droopy, it is almost certainly the result of overwatering.
You can feel the soil to double-check this. If it is wet, chances are your pencil cactus has become overhydrated.
It is important to remember that succulents can survive for long periods of time in extremely dry environments, such as deserts, so you should only be watering your pencil cactus every couple of weeks.
A serious consequence of prolonged overwatering is root rot. This is a condition caused by prolonged exposure of the plant’s roots to waterlogged soil, so that they eventually drown and die. The dead roots will start to rot, and will be susceptible to opportunistic pathogens such as fungi and bacteria, which will make the rot more aggressive and cause it to spread faster to the rest of the plant. Soon, the entire plant will be consumed by the rot, by which time it is likely too late to save it.
If you think your pencil cactus has been overwatered, stop watering it immediately. Move it to a sunnier area where the warmth from the sunlight, along with good air circulation, will help the soil in the pot dry out faster, along with the plant’s roots.
Do not water the plant again until the top two inches of soil in the pot have dried out. If the top two inches of the soil are still a bit damp, wait one or two days and check again.
If you suspect root rot, you will need to repot your plant. To do this, remove the plant from its old pot, taking care not to damage the fragile roots. Wash off as much soil as you can from the roots and inspect them for sections that have turned brown or black. These roots are rotten and will need to be removed using a sterile knife or pair of scissors. Prune away all of the rotten roots until only healthy, white roots remain.
Then, place the plant on a dry surface and allow the roots to air-dry for several hours.
Prepare a new pot by filling it with fresh, well-draining succulent potting mix, and place the plant in the middle of the pot. Cover the roots with more soil, and place the plant in a spot where it can get bright light and good air circulation.
Do not water the plant until the top two inches of soil are dry to the touch. You should also make sure that the pot you are using has drainage holes at the bottom. The drainage holes will help get rid of any excess water that might accidentally end up in the pot, thus lessening the chances of overwatering and root rot.
Not enough water
Succulents in the wild are good at conserving water for later use, but remember that, when it does rain, they generally receive more than a few drops of water.
In nature, rain can fall for a few minutes or several hours at a time, giving plants ample time to absorb the moisture they require. So, while succulents do not need to be watered as often as other houseplants because their bodies can hold water, this does not mean you can neglect to water your plant for extended periods as and when you feel like it.
If the soil in the plant’s pot dries out, the plant will turn to its water stores to keep itself alive until the next rainfall, or the next time you remember to water it. The longer the soil around the roots remains dry, and the longer the plant is deprived of water, the drier the foliage will become, turning yellow or brown and starting to curl and shrivel. This is the plant’s way of preserving itself, but prioritizing its resources for the parts that are most crucial to its survival, such as the stems and roots.
If you think that your pencil cactus is shriveling due to underwatering, you need to water it as soon as possible. Soak all of the soil in the pot until excess water flows out of the drainage holes at the bottom. This is so that all the roots can get their fair share of water and none are left wanting.
Water your pencil cactus approximately once every two weeks, making sure to give it a good soaking each time.
If your plant has begun to wrinkle, you may need to water it once a week for a few weeks, after which you can reduce your schedule back to once every two weeks.
Also make sure to keep an eye out for any yellowing, which is a sign of overwatering.
Maintaining good watering habits will always be the best way to ensure that your pencil cactus is neither overwatered nor underwatered. Rather than following a set watering schedule, adjust the frequency according to the local weather and climate. The most important thing to remember is to water the plant when the top two inches of soil are dry to the touch. If the soil still feels a bit damp, wait one or two days before checking it again.
Incorrect soil type
As we have already mentioned, using the wrong type of soil for your pencil cactus can result in drainage problems for the plant.
Densely-packed soil will prevent water from draining properly, and your plant is more likely to suffer from overwatering and root rot. This is why regular potting soil, by itself, is never a good choice for succulents.
Make certain that at least one-quarter of your potting mixture is composed of sand, perlite, or vermiculite. If you want to create a natural filtration system for excess moisture, you can also add rocks or gravel to the bottom of the pot.
You can purchase a potting mix designed specifically for succulents, but you can also make your own at home. Just make sure you incorporate any of the above mentioned drainage components in order to promote better drainage for the plant.
Pencil cactus care
The pencil cactus thrives in full sun, which means at least six hours of direct sunlight per day. That said, it can tolerate a little shade and may even benefit from some protection from the hot afternoon sun. Indoors, place it near the brightest window available. If you live in a place where natural light can be scarce for a few months of the year, you might have to use a grow light to help meet your plant’s light requirements.
This plant prefers a dry, sandy soil that is not particularly nutrient-dense. Container plants do best in a potting mix made for succulents that does not retain moisture too well. Also make sure the pot that you choose for the plant has drainage holes at the bottom.
The watering requirements for this succulent are very simple. During the spring and summer, it only needs watering every two to three weeks. This should be reduced to once a month during the fall and winter. It is preferable to allow the soil to dry completely between waterings in order to avoid any chance of overwatering.
Temperature and humidity requirements
The optimal temperature range for the pencil cactus is 65 to 75 degrees Fahrenheit, and it should never be allowed to fall below 50 degrees. Indoors, make sure to keep your plant away from cool drafts, such as those generated by an air conditioner.
Low humidity is best for the plant’s growth, but as long as the soil does not retain moisture, a higher relative humidity should not be a problem.
This plant is not a heavy feeder in the traditional sense. Provide it with a balanced liquid houseplant fertilizer in the spring, according to the instructions on the packaging, and it should be fine for the rest of the year.
The pencil cactus is a beautiful, unique-looking, low-maintenance succulent that is native to Asia and Africa.
This plant is not especially prone to many problems, but one of its most commonly-observed issues is shriveled foliage.
If your pencil cactus is shriveling, it is a sign that an environmental factor is causing it stress. You will need to identify the cause of the stress in order to solve the problem promptly and effectively.
The most common causes of a shriveling pencil cactus are too much water, not enough water, and incorrect soil type. The sooner the cause of the problem is determined, the faster the treatment can be, and the sooner the plant will be saved.
Image: istockphoto.com / Linjerry