What is the Cause and Controversy of Variegated Houseplants?

One variegated houseplant has recently caused so much controversy that it has made it into some general news outlets.

Commonly called the Pink Congo, it is a type of Philodendron that produces pastel pink leaves.  These plants became extremely popular and were being sold for up to $200 a plant.

Then earlier this year, the process used to produce these plants was exposed by a popular plant YouTuber and shop owner, Kaylee Ellen of The Rare Plant ShopIt turns out that the pink color was chemically-induced and not permanent.  Manufacturers were using a chemical that temporarily prevented the plant from creating chlorophyll, producing pink-colored leaves.  Once the chemical wears off (within approximately 6 to 12 months) the leaves revert to green.

The plants were originally produced for special-themed events where people would only be utilizing them short-term.  However, they started being sold as houseplants without attaching information about the impermanent color, much to the disappointment of their owners.

While most variegation in plants is not chemically induced, this controversy did spark an interest in me to learn more about the science of plant variegation.  To find out what I learned, keep reading! 

As for the Philodendron ‘Pink Congo’, I think its time has mostly past, BUT you can still find it for sale online (complete with a pretty high price tag as of this post’s publishing) without much effort.

Table of Contents

What causes variegation?

The term “variegated” comes from the word variegatus in Latin which means composed of various colors. This beautiful array of colors is caused by some of the plant’s cells lacking chlorophyll. Chlorophyll is the green pigment in plants that works to convert light into energy the plant can use.

Some plants are variegated in nature. Many of these plants are found on the forest floor, where it is more important to have camouflage from herbivorous creatures than chlorophyll. The variegated plants can use their coloration to appear as if they have eggs laid on them already, been eaten, sickly, or not as easily visible. This provides them an advantage over other fully green foliage.

Many plants we keep in our homes, however, do not consistently appear variegated in nature (as this would make them more visible and less able to photosynthesize), so these variegations have been propagated and/or cultivated by us humans.

5 Types of Variegation

Each type of variegation can tell you a lot about the plant, how it can be propagated, and its care!

Genetic Variegation

Genetic variegation is inherited or passed down from generation to generation. This makes it very stable and easily propagatable.

Chimeric Variegation

Chimeric variegation is randomly occurring so it is not predictable. Plants with chimeric variegation are often described as mutants because it is cell mutations that cause the variegation. Because they are randomly occurring, these patterns are not stable or consistent. To maintain the variegation you generally have to propagate it from a variegated piece of plant. Even then, it isn’t guaranteed to remain stable!

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Blister or Reflective Variegation

Blister or reflective variegation is a type of variegation formed by air pockets that exist between the outer leaf layer and the inner pigmented layer of the plant. When light hits the air pockets, it creates a shimmery, reflective patch that is quite stunning. Often these areas can seem sparkly or silvery, even.

Viral Variegation

Viral variegation is caused by infection.  It is stable as long as the infection is present, but not necessarily good for the plant.

The one infection that I am most aware of is Dasheen mosaic virus (DsMV), which can affect many species of plants and often expresses as a feathering pattern along the veins of leaves.

This can actually be quite beautiful, but the virus weakens the plant dramatically and is easily spread. As such, the current recommendation for plants with this virus is elimination because it is incurable.

Alocasias, like my Alocasia ‘Frydek’ pictured below, are one Genus of plant that is susceptible to this virus. However, young leaves can also show this feathering without having DsMV. Here you can see my Alocasia ‘Frydek’s new leaf with feathering along the vein. However, within a couple months, the feathering has faded and the leaf is now fully green like its more mature leaves.

Artificial Variegation

Artificial variegation – I added this category because I felt that the Philodendron ‘Pink Congo’ deserved a category, even if its variegation isn’t lasting.

Artificial, in this case, means that the plant does not produce the variegation within its cells naturally (whether through cultivation or natural mutation). Instead, humans add something to the plant so it becomes or appears variegated, like the chemical used to produce the Pink Congo.

There are other means people have found to create variegated plants as well, though they are not quite as convincing, fortunately, for us buyers.

Companies paint on variegation or glue on decoration (which I realize would not be variegation), most often with cacti or succulents. My personal rule of thumb here is – if it looks too good to be true, it probably is.

Here are pictures of three succulents that have been painted with their accompanying label:

Here’s an example of a cactus that has a fake flower glued on top:

How to care for variegated plants?

Because chimeric variegated plants are unstable mutations, a change in conditions (especially not enough light) can cause the plant to revert to green. The plant needs these green areas to convert light into energy and if it isn’t getting enough light, then it needs more surface area to absorb as much light as it can. To survive, it will ditch those beautiful variegated areas for the more efficient green.

If you notice your plant beginning to produce green leaves instead of variegated leaves, try moving your plant to an area with more light.

Horticulturists also recommend cutting off all-green parts of variegated plants because once the plant begins to produce fully green foliage it will continue to revert to maximize energy production. Removing those sections should retain the plant’s ability to produce variegated foliage as long as the other conditions it needs are available.

Below shows a picture of my Hoya carnosa ‘rubra’ on the left. It started producing a vine that was completely green. I removed the vine and propagated it. That vine is now rooted in its own pot, pictured on the right.

The green plant would now be referred to as Hoya carnosa ‘Green Exotica,’ I believe. The upside of reverting plants is that you can make yourself a whole new plant if you’d like!

Want to learn more about photosynthesis? Click here to expand!

The word, “photosynthesis,” comes from the Greek words “photo” and “synthesis.”

Photo means ‘light’ and synthesis means ‘putting together.’

So combined these words mean ‘putting together with light.’ 

In this case, plants are putting carbon dioxide and water together using light’s energy to produce glucose or food. Plants take in carbon dioxide through tiny pores called stomata or stoma. They get water from their soil or from water running over their aerial roots and leaves.

During the process of creating glucose, extra oxygen atoms are leftover and released that we can breathe in!

For those who like chemistry, here is an equation that shows how carbon dioxide (CO2) and water (H2O) combine to create glucose (C6H12O6) and oxygen (O2).

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1 Comment


    Which chemical use for philodendron pink congo ?



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