Christmas cactus, Schlumbergera spp., is likely one of the best houseplants to develop.
Not a desert cactus, however an epiphyte, it’s one in all quite a few species and hybrids of rainforest crops that cling harmlessly to timber and rocks for help, drawing sustenance from the air, rainfall, and leaf litter of their instant surroundings.
In our information to rising Christmas cactus, we share perception on finest practices for cultivation.
On this article, we discuss why the segmented inexperienced stems of a Christmas cactus generally flip purple.
Right here’s what’s in retailer:
Why Christmas Cactus Might Flip Purple
Crops could not be capable of communicate, however they will nonetheless talk with us, and tell us they’re burdened.
A method a Christmas cactus lets us comprehend it’s in hassle is by placing out thread-like aerial roots from between the stem segments.
You possibly can study extra about why Christmas cactus develops hair-like roots right here.
One other is for the stem segments to morph from their pure vibrant inexperienced to shades of purple, together with purple and pink, in response to demanding environmental situations.
The 4 almost definitely causes for purple-hued discoloration are: brilliant gentle, inappropriate moisture, nutrient deficiency, and excessive temperature fluctuations.
Let’s think about these stressors and methods to keep away from them.
1. Shiny Mild
A probable purpose for purple coloration is publicity to brilliant, direct daylight.
When a plant is genetically wired to develop within the sun-dappled shade of a rainforest cover, an overabundance of sunshine could set off a safety response to the ultraviolet (UV) rays.
As an alternative of presenting with chlorophyll-rich inexperienced stems, the life-threatening brilliant gentle induces UV protecting phenolic compounds known as anthocyanins to dominate with their purple pigment.
A Schlumbergera that’s left to deal with extreme daylight will seemingly scorch, which might harm stem tissue past restore.
This harm prevents it from absorbing daylight, and jeopardizing photosynthesis, the conversion of daylight to meals.
Keep away from this concern by selecting a location with oblique, or filtered daylight, ideally going through north or west.
2. Inappropriate Moisture
Failing to accommodate the necessity for water could trigger stress-induced shade modifications. Each under- and overwatering could also be culprits.
Underwatering
An underwatered plant could flip purple earlier than drying to a brittle, lifeless brown.
Water is as important as daylight, and an absence of sufficient moisture inhibits photosynthesis. Moreover, a really dry surroundings could cause the plant to develop into burdened.
In the event you discover that your property is dry throughout the winter, place a shallow pan of water in entrance of a warmth register and sanitize it every time it dries up.
Because the water evaporates, it provides moisture and humidity to the air.
One other evaporation technique is to put your potted cactus on a mattress of gravel in a shallow pan. Add sufficient water to cowl the gravel.
It’s also possible to group houseplants collectively, and mist them often to duplicate the tropical moisture to which rainforest cacti are accustomed.
Overwatering
The flip facet, overwatering, could trigger leaves to yellow, and in excessive instances, tackle a purple to brown forged earlier than turning mushy.
Extreme over- or underwatering could prolong all the way in which to the roots.
Air is one other photosynthesis important. When roots are waterlogged, they can not breathe, posing a lethal problem to the meals manufacturing course of.
To stop moisture-related stress, use a pot with an ample drainage gap. Use a potting medium that’s free and well-draining.
Study extra about the precise potting combine on your Christmas cactus right here.
Water solely when the highest one to 2 inches of potting medium really feel dry.
In the event you’ve oversaturated your plant, you might be able to dry issues out by digging the cactus up, rinsing its roots, slicing off any rotten patches, and repotting it in evenly moistened medium.
As a final resort, if the plant is severely broken, you might be able to salvage no less than a little bit of stem phase or root that haven’t rotted, to propagate a complete new cactus.
Discover extra recommendations on saving an overwatered Christmas cactus right here.
3. Nutrient Deficiency
And eventually, your plant’s purple section could also be the results of a deficiency in a number of important macronutrients, together with magnesium, nitrogen, and phosphorus.
Malnutrition could happen due to:
Poor high quality potting medium from the beginning
Nutritionally depleted potting medium because of years of use
An especially tight tangle of roots that may’t take up vitamins from the potting medium
Root harm from transplanting, unintended harm, pests or illness, or improper watering
To treatment nutrient deficiencies, use a high quality potting medium and repot as wanted in a barely bigger pot, as Schlumbergera prefers a cosy, however not densely rootbound match.
Some people apply a extremely diluted Epsom salts resolution (one teaspoon per gallon of water), however this presumes that the deficiency is magnesium.
You may give this a strive, but when it doesn’t work, apply a well-balanced, slow-release all-purpose houseplant fertilizer to handle all potential macronutrient deficiencies.
Study extra about fertilizing Christmas cactuses right here.
You’ll want to water correctly, and look ahead to indicators of insect infestation or progress anomalies which will counsel illness.
4. Temperature Extremes
The extreme warmth related to brilliant direct daylight is a contributing issue to reactive discoloration, as a plant makes an attempt to guard itself from the demanding local weather situation.
Equally, chilly temperatures could invite the identical response, identical to we see on outside perennials which have skilled chilling temperatures, however not a decimating frost.
To keep away from temperature-induced discoloration, preserve your cactus in a room with a temperature vary of 70 to 80°F.
A brief-term change in temperature is important throughout dormancy, to organize a plant for blooming, which you’ll be able to study extra about in our information to encouraging your Christmas cactus to flower.
This requires six to eight weeks of fifty to 55°F temperatures, and lengthy darkish nights that mimic a pure winter.
Reduce temperature fluctuations by inserting your pot in a location away from drafts from home windows, warmth registers, and exit doorways.
I’m Speaking to You
One of the best ways to keep away from triggering stress in your plant is with a constant routine of excellent horticultural care. Generally, nevertheless, situations are lower than very best.
Shading to purple offers a visible cue that one thing is amiss. In the event you see this, study your gardening practices and the indoor surroundings for the next:
Mild that’s too intense.
An excessive amount of or too little moisture.
Depleted soil or extraordinarily sure roots.
Temperatures that overheat or chill.
Hearken to your plant’s cry for assist and act shortly.
Until the consequences of the stressors have progressed to desiccation or rotting, you’ll be able to often restore a cactus with a change of location and/or extra vigilant care.
If it’s too far gone, you might be able to discover a wholesome little bit of stem or root to snip off and use to propagate a complete new plant.
Cultivating Christmas cactus is straightforward once you “pay attention” and reply.
Has your Christmas cactus ever turned purple? Tell us within the feedback under and share your suggestions!
In the event you discovered this text informative and wish to broaden your data of Christmas cactus care, try the next guides subsequent:
© Ask the Consultants, LLC. ALL RIGHTS RESERVED. See our TOS for extra particulars. Initially revealed December 13, 2020. Final up to date November 6, 2026. Uncredited images: Shutterstock.
