The Christmas Cactus is one of your 99 problems. It’s not easy to grow, even though its name includes the word “cactus.” Like all plants, they have their fair share of problems. However, by diligently attending to your Christmas Cactus problems, they’ll bloom happily once again. This guide will help you revive your Christmas Cactus with ease. Top tip: the trick lies in identifying the exact cause.
It’s important to know the basic facts about the Christmas Cactus. Having a good understanding of the plant will allow you to prevent future Christmas Cactus problems.
Even though Christmas Cacti are a genus of the cactus, they’re not from the hardy deserts. They fall into a small genus category of cacti called Schlumbergera, which are a type of tropical cacti. They thrive in humid shady forests found in the tropics. This plant does not grow on the ground but on the branches and nooks of trees. It anchors itself on the rotting vegetation trapped on the tree.
The Christmas Cacti flowers in winter. Therefore, for them to bloom they need a suitable light cycle. On average, they need 16 hours of darkness and 8 hours of light to start their bloom cycle. A cool and dark environment is all they need to bloom.
The Christmas cactus (Schlumbergera bridgesii) is a popular holiday houseplant known for its colorful blooms that appear near Christmas However, the flattened green stems of this epiphytic cactus can sometimes become afflicted with mysterious white spots. These blemishes definitely detract from the plant’s beauty.
If you notice white marks marring the attractive pendant stems and branches of your Christmas cactus don’t panic. In most cases, the spots are merely cosmetic damage and not a sign of serious disease. With proper care the plant can often outgrow the problem over time.
Read on to learn what causes white spots on Christmas cactus and how to prevent and treat them
What Causes White Spots on Christmas Cactus?
White spots or markings on Christmas cactus are usually caused by one of these factors:
Sunburn
Too much direct sun can burn or bleach the tender green skin of the stems, leaving white sunken lesions behind. This often occurs if the plant is moved from indoors to full outdoor sun without slowly acclimating it first.
East or west-facing windows indoors are ideal for Christmas cactus. Outdoors, keep it in partial shade protected from intense afternoon sun.
Mineral Deposits
White crusty deposits on the surface are generally a buildup of mineral salts, such as fluoride, chloride and boron.
Tap water and softened water contain salts that can leave these white marks if allowed to dry on the leaves and stems. Avoid wetting the foliage when watering. Improve drainage and provide even moisture to discourage deposits.
Pest or Disease Damage
In some cases, white spots can indicate an underlying pest infestation or fungal disease:
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Mealybugs – These small soft-bodied insects produce white waxy secretions that coat the cactus, leaving a white cottony residue on the stems.
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Scale insects – Hard brown bumps on stems may be armored scale. Feeding by the immobile insects removes plant fluids, leaving white lesions.
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Fungal leaf spot – Various fungal pathogens can cause small, sunken white spots surrounded by a red, yellow or black ring. This is more common on Schlumbergera leaves than stems.
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Root rot – Overwatering can lead to deadly root rot. This may produce wilting, yellowing and white sunken spots on the stems before killing the plant.
So inspect closely to determine if pests or disease are contributing to spotting before choosing treatment. Gently rubbing the spots with your finger can help identify whether it is scale, mealybug or fungal in origin.
How to Treat White Spots on Christmas Cactus
If your diagnosis concludes the white marks are caused by sunburn, mineral buildup or pests, use these treatment tips:
Adjust Sun Exposure
If sunburn is causing bleaching, move the potted cactus to a shadier spot indoors or outside. Slowly introduce it to increased sun over a period of weeks to months. White sunken lesions from previous burn will gradually fade or may peel off as the plant produces new growth.
Remove Mineral Deposits
Use room temperature distilled water or rainwater to avoid adding more salts and minerals. To remove existing crusty deposits, dip a soft cloth in distilled vinegar and gently wipe stems. Avoid wetting the foliage. Improvement will be gradual since marks fade slowly as stems elongate. Trim off severely affected segments.
Treat Pest Infestations
Mealybugs, scales and other sap-feeding insects can be controlled with sprays of insecticidal soap, neem oil or horticultural oil applied every 7-10 days. Systemic insecticides added to the soil may be warranted for heavy infestations. Isolate treated plants from uninfected ones to prevent spread.
Be sure to follow label directions and test products for safety on a small section of the plant first. Remove severely infested stems to improve control.
Improve Growing Conditions
The key to avoiding future blemishes is adjusting care to provide the ideal environment:
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Water only when the potting mix is partly dry. Avoid moisture extremes.
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Use a well-draining cactus mix and pot with drainage holes.
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Increase humidity around the plant.
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Fertilize monthly in spring and summer with a balanced houseplant food diluted to 1/2 strength.
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Keep temperatures around 65-75°F during fall and winter.
With attention to proper growing conditions and prompt treatment if spots occur, you can maintain a healthy, vigorous Christmas cactus free of these cosmetic flaws. Any current white blemishes should fade over time as the cactus produces new pristine growth.
Is It Fungal Leaf Spot Disease?
While pests, sunburn and minerals are the most common causes of white spots on Christmas cactus, occasionally they can indicate a fungal infection. Let’s look at how to identify and treat two types of fungal leaf spot diseases:
Bipolaris Leaf Spot
This fungal disease produces round white sunken spots edged in reddish-brown rings on leaves and sometimes stems. The lesions may spread or merge to form larger dead patches. It is caused by the Bipolaris species.
Bipolaris leaf spot thrives in warm, humid conditions. Avoid overhead watering and provide good air circulation. Remove and destroy affected leaves. Treat with fungicides containing mancozeb or neem oil sprays.
Phyllosticta Leaf Spot
Small round white spots form on leaves, outlined by a yellow halo. The lesions become tan colored with dark brown borders as they age. It is caused by Phyllosticta schlumbergerae.
Prevent conditions favorable for disease like overwatering, humidity and dense foliage. Apply fungicides with chlorothalonil or mancozeb when symptoms are first noticed. Remove severely affected leaves.
Is It Root Rot?
While leaf spot fungi usually don’t affect the stems as much, the fungal disease root rot can cause widespread yellowing or white spots on Christmas cactus stems. As the roots die off from excess moisture, the plant is unable to take up water and branches start collapsing.
To treat root rot, allow the potting mix to completely dry out. Remove the plant and trim off all black, mushy roots. Repot in fresh cactus mix with added perlite for drainage. Water sparingly, allowing the soil to partially dry out between waterings. Discard any badly affected cuttings.
With diligent care, the Christmas cactus can grow new healthy roots and stems will firm up again as proper watering resumes. Disinfect any pots before reuse to avoid spreading disease.
When to Seek Professional Help
Consult with your local nursery, horticultural extension office or plant disease expert if:
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Spots continue to spread rapidly despite treatment.
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You are unsure if it is pest, disease or cultural issue.
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The plant declines despite your best efforts to fix the problem.
They can help positively identify if disease is the cause and recommend appropriate fungicides or treatment measures. This is especially prudent if you want to protect other cacti in your collection from potential infection.
Don’t let a minor case of white spots detract from the graceful elegance of your prized Christmas cactus. With some detective work and attentive care, you can restore its unblemished beauty to enhance your holiday decor.
Dire Christmas Cactus problems
If these things happen to your Christmas Cactus, it will be hard to get better. But if you follow these steps, we’re sure you’ll be able to get a happy Christmas Cactus.
My plant is wilting and it has black spots all over it. The leaves have turned brown.
Symptoms: The plant is wilting. Black and red spots on the plant. The spots have a watery texture to them. The leaves of the plant are browning.
Cause: Overwatering and root rot.
This is very common when it comes to Christmas Cactus problems. The culprit is root rot. Act quickly. Overwatered Christmas Cactus care should be administered with immediate haste if you want to save your plant!.
Start by unrooting the Christmas Cactus and washing the soil off the roots. Take a pair of sharp, clean plant scissors and snip off the rotten chunks of the root. If the roots are rotten they should feel squishy.
Get a clean pot with drainage holes at its bottom. Fill the pot with cactus soil and lightly water to make it moist. Let the water drain off. Do not make the soil too moist or you will start the rot all over again. Re-pot the plant and observe it for a few days.
Only water the plant when the soil goes dry. If your Christmas Cactus starts to shrivel, this is a good sign that you need to water. Once watered, remove excess water from the tray below to ensure the soil doesn’t sit in it.
Avoid using fungicides! This is indeed caused by fungi, but you need to know the exact variant to treat it. It is easier to re-pot the cactus and give the plant a second chance.
Christmas cactus dropping segments, leaves or flower buds. Save your succulent plant
Why are there white spots on Cactus?
White spots on cactus become an alarming sign when they appear on attractive cacti and ruin the aesthetics of the plant. Cacti require less care, water, and precision than most non-succulent plants making them suitable for busy plant-lovers.
What causes yellow spots on a Christmas cactus?
Yellow spots on a Christmas cactus can derive from several conditions, including root rot, sunburn, or stem rot. However, the last one, Basal stem rot, can potentially be deadly for your plant if not treated immediately, so you should check for signs of this disease before treating your plant for secondary issues.
What causes brown spots on Christmas cactus leaves?
Brown spots on the leaves of your Christmas cactus are common. They can be the consequence of sunburn or sunscald, especially if they appear where the leaves are at their thinnest, usually along the edges. However, in most cases, these spots are relatable to Botrytis blight, a fungal disease that affects millions of plants worldwide each year.
Why is my Christmas cactus turning white?
Christmas cactus plants will turn white due to leaf scorching or underwatering. If left in direct sunlight the UV rays can bleach the color from the leaves. Underwatering can also rob the foliage of nutrients needed to maintain color pigmentation. So how do you treat a christmas cactus that has yellowing foliage?