Ever wonder what causes variegation in your houseplants, why variegation changes or reverts, or why some variegated plants are insanely rare and expensive?
In general, variegation refers to foliage with multiple colors. Let’s go over the five different reasons that variegation emerges in foliage.
1. Pattern-Gene/Natural Variegation
In the words of Lady Gaga “Oh there ain’t no other way, baby I was born this way”. Natural variegation is literally in the plant’s DNA. As such, the patterning is inheritable so cuttings and seeds from a plant will have the same variegation as the parent. This type of variegation is also stable — it won’t have random variations from one leaf to the next.
Examples of pattern-gene variegation are: fishbone prayer plant (Ctenanthe burle-marxii), rattlesnake calathea (Calathea lancifolia) and variegated spider plant (Chlorophytum comosum ‘vittatum’)
If the patterning is in the genes, that suggests an evolutionary purpose — a benefit to the plant that helps protect it from predators or procreate. In the case of plants, predators are actually herbivores! Scientists suspect variegation may help plants camouflage or appear undesirable to eat (as though they are sickly, poisonous, or have eggs laid on them). Are you looking at your polka-dot plant differently now? Sorry…
The natural variegation we see in many houseplants today is the result of breeding: the patterning was accentuated and manipulated by growers through selection and breeding hybrids. The results are ‘cultivars’, not native plants as they would appear in the wild. Think of cultivars like designer dog breeds — you won’t find packs of teacup poodles or puggles in the wild!
You can discover whether a variegated plant is a cultivar or not from its name: if you see variegata (lowercase, italics) as the second part of the latin name this plant is a naturally occurring species; if instead you see ‘Variegata’ (uppercase V in single quotations) in the plant name this indicates that the plant is a cultivar.
2. Chimeral Variegation
Chimeral variegation is the most common type of variegation. It results from genetic mutations that inhibit some layers of the leaf structure from producing chlorophyll (the green pigment in leaves that converts sunlight into energy for the plant).
Visually, we see these mutated layers as white, yellow or light green patches on an otherwise green leaf. Variegated Monstera deliciosa is an example of chimera variegation.
Plants with chimeral variegation may have a mix of speckled leaves, solid white leaves, and solid green leaves. It is also possible for a consistent chimeral variegation pattern across all leaves of a plant.
The Kalanchoe below is a perfect example of random, unstable chimera variegation. The plant started with white-tipped green leaves and is now producing new shoots with solid white leaves and solid green leaves.
Chimeral variegation differs from pattern-gene variegation because the mutation is random and unstable — the plant’s pattern may change or even revert to solid green and reproducing the variegation pattern through propagation is generally a roll of the dice. For this reason, some chimeral variegated cultivars are difficult (and expensive) to buy.
3. Blister/Reflective Variegation
Silvery or reflective spots on foliage come from air pockets (blisters) between the outer membrane of the leaf and the pigmented layer of the leaf (which contains green chlorophyll). The air pockets reflect light hitting the plant, which creates a sparkling silver look. You’ll find that these leaves appear variegated on top, but look solid on the underside of the leaf.
Blister variegation patterns can appear consistent across an entire plant, as is the case with watermelon peperomia, or random, like the blotches found on satin pothos. In both cases (random or consistent patterning) the variegation is part of the plant’s DNA and is, therefore, reliably passed along through propagation from cuttings or seeds.
Blister variegation is also responsible for the striking appearance of white veins on some Anthuriums, Alocasias and Philodendrons. Some specific examples are: Anthurium clarinervium, Alocasia frydek and Philodendron gloriosum.
The evolutionary purpose of blister variegation is providing a bit of sunscreen for the plant cells. When plants receive too much sunlight it can cause photoinhibition (a reduction in the plant’s ability to photosynthesize).
4. Viral Variegation
Sometimes a virus is responsible for leaf variegation, as is the case with Mosaic virus. Sometimes this variegation is desirable and reproduced as cultivars. For instance, some hosta cultivars owe their variegation to a virus.
5. Chemical variegation
Plant manufacturers can use chemicals and dyes to temporarily change the color expression of leaves. For example, manufacturers produced the Pink Congo Philodendron by feeding it a chemical that temporarily prevented the plant from creating chlorophyll, resulting in pink leaves. However, once the chemical wears off after six to twelve months, the leaves revert to green.
The Pink Congo Philodendron created quite the uproar among houseplant enthusiasts because these pricey plants were sold without disclosing the artificial and time-limited nature of the variegation!
Can I create variegation in a normal plant?
While this would be really cool, unfortunately it is not possible for a plant enthusiast to intentionally induce variegation at home.
What causes variegation to revert?
When dealing with chimera variegation, sometimes there is no rhyme or reason: producing solid green leaves is just part of the randomness. However, sometimes variegated plants revert because they aren’t getting enough sun.
If you think about it, leaves with variegation are less efficient at consuming sunlight because they have patches without energy-producing chlorophyll. Reverting to solid leaves helps a plant produce more energy with the same amount of sunlight available to it.
My plant is losing its variegation — what can I do?
As mentioned above, a plant will often benefit from solid leaves because they have more chlorophyll to convert sunlight into energy for the plant. To keep reverting leaves at bay, try increasing your plant’s sun exposure and trim away the solid leaves to discourage it from putting out more.
Why don’t my albino leaves last?
Albino leaves have no chlorophyll and, although we love them, they are basically useless for the plant. Well they’re a burden, really, because they don’t produce any energy for the plant, but require energy from the plant to keep going. As such, plants aren’t really motivated to hold onto their albino leaves and are more likely to drop those leaves as dead weight.