One of the most fascinating aspects of Christmas Cactus (Schlumbergera x Buckleyi) is the fact that this plant is technically leafless.
Instead, the segmented, succulent stems serve the same function as leaves and are often referred to as the plant’s leaves.
While this makes the Christmas cactus plant and its two sister plants, the Easter cactus (Schlumbergera gaertneri) and Thanksgiving cactus (Schlumbergera Truncata), rather unique and appealing; it also means the signs of health issues may be a little different from other plants.
A good example of this is wilting, which may present itself as sagging, limpness or wrinkling.
When a Christmas cactus begins to wilt, it can be a sign of many potential problems, some of which can be deadly to the plant.
Why Is My Christmas Cactus Wilting?
Finding the answer to this problem is usually a process of elimination.
Begin with the most easily spotted symptoms and work your way down until you find the source of the wilting.
Improper Watering
Perhaps as much as 80% to 90% percent of all Christmas cactus issues can be traced back to watering issues.
Not enough water can result in wilting Christmas cactus as well as a reddening of the leaves.
Excess water, however, can not only cause wilting, but may also lead to root rot.
Stick your finger into the fast-draining soil and check the moisture level.
If the potting mix is too dry, add some water, but if it feels soggy, you will need to transplant your cactus to fresh soil, checking for root rot when you do.
Having too much water can lead to infestations, fungal problems, and many other issues that can harm or even kill your plant.
The best way to avoid this problem is to use the4 soak-and-dry method to water your cactus.
Note that exposing the plant to too much light can dry out the soil faster, while too much shade will slow evaporation, so you may need to move the plant if watering issues persist.
Related: More on Watering Christmas Cactus
Infestations
Aphids, fungus gnats, mealybugs, scale, spider mites, thrips, and whiteflies are all potential problems for your Christmas cactus and may cause wilting as they feed on the plant’s sap.
Of these, it’s especially important to watch out for fungus gnats and thrips.
Fungus gnats are a sign that your plant or its soil has a fungal infection.
Thrips can be an even bigger threat, as they’re vectors of INSV (impatiens necrotic spot virus).
While Christmas cacti are often asymptomatic, an infected plant can transmit the virus to other nearby plants where it can do severe damage.
All of these pests can be prevented by giving your cactus a neem soil soak every 2 to 3 weeks and maintaining good care practices.
Compacting and Rootbound
These two problems are somewhat related as they both directly impact the roots.
As an epiphyte, Christmas cactus gets most of its nutrients from the air, but still relies on its roots for some of its needs.
Christmas cacti like to be a little rootbound, but too much overcrowding will prevent the roots from properly getting food and water, leading to wilting.
Likewise, if the soil becomes too compacted, this can make it harder for the roots to get what they need.
Repotting your Christmas cactus every 3 years or so will allow you to change the soil and increase the pot size, if needed.
This is a good time to check root health and remove any signs of damage.
You may also wish to add perlite or another aggregate to improve drainage and reduce the risk of soil compacting.
Humidity
As mentioned, these plants are epiphytes, so a decent humidity level of 50 to 60% percent is necessary for a happy and healthy plant.
Too much humidity can lead to fungal infections and possible infestations.
However, too little humidity will dehydrate your plant.
Plants actually sweat out 97 to 99% percent of the water they absorb as a means of cooling off and keeping itself properly hydrated.
This process, called transpiration, is a vital function in the environment.
Christmas cacti actually get some of their nutrients and water from the air around them, so low humidity will cause them to both lose a source of water and some of their stored water as well, resulting in wilting.
Use a hygrometer or the sensors on a nearby humidifier to check and make sure humidity levels are appropriate.
If not, supplement with the aforementioned humidifier or a pebble tray to get the plant’s local humidity levels up to the proper level.
Root Rot
One of the most dreaded diseases out there, root rot can easily kill most plants and occurs primarily as a result of overwatering.
However, there’s both a bacterial and fungal cause for root rot, so purchasing contaminated soil can also result in this dangerous disease.
If the soil is soggy or you have exhausted all other possibilities, uproot your cactus and examine the roots. Infected roots may be blackened or visibly sick.
Using a sharp, sterile knife, cut away these damaged roots above the infected tissue and resterilize between each cut.
Caught early enough, a Christmas cactus can bounce back from root rot, but advanced cases may prove terminal.