Variegated plants originate naturally as random seedlings, or as sports - mutant variegated shoots on otherwise plain green plants. Some, such as Abutilon pictum 'Thompsonii', are virus-induced, in the same way that the streaked colours of 'Bizarre' tulips result from a harmless virus.

In red-or purple-variegated plants, chlorophyll, the green pigment responsible for photosynthesis and vital for non-parasitic plants' survival, is masked by other pigments, anthocyanins. Yellow and white variegations are caused by imperfect or absent chloroplasts, the granule-like plastids within a cell which contain chlorophyll.

In a white- or yellow-edged leaf, the green pigment functions normally in the inner layer of leaf cells, but the outer layer lacks chloroplasts, making the edges white, or contains a preliminary version of chlorophyll, protochlorophyll, creating yellow.

A yellow- or white-centered leaf, with green edges, has a defective inner layer of leaf cells. The attractive pink, red or russet spring flushes that some variegated leaves have result from anthocyanins protecting the vulnerable new growth from harsh ultraviolet light rays. Autumnal flushes result from an accumulation of sugar in the leaf tissues, caused by a drop in night temperatures which triggers the production of anthocyanins and anthoxanthins.

(All great stuff, but here's where I think it gets really interesting - and useful.)

The intensity of leaf colour is affected by the amount of light available. There are exceptions, but generally, variegated plants with glaucous foliage, such as rue and certain hostas, tolerate more sun than all-green kinds. Those with purple, maroon and brown variegations colour most intensely in sun, often becoming dirty green in shade. Yellow-variegated leaves colour best in full sun or light shade. White- and cream-variegated leaves, such as variegated apple mint, tend to prefer shade, especially where the soil is dry. With those that are happy in sun or shade, variegation is often sharpest in sun, but if it is combined with dry soil, smaller leaves and more compact growth result."

So, in a nutshell, some plants are more colorful or pronounced in shade and others in more sun. So which plants do you have that are as colorful as "the pictures out there?" And what is their sun situation? Any other general variegation comments? I love the way the same Coleus plants will look totally different in sun vs. shade.

For the 2 kinds of Dracaena marginata trees I have, I've seen the best colors with more sun, a few hours direct, time of day doesn't seem to matter.

I don't know if my older Sans leaves faded because that's what old leaves always do or from not enough sun for years at a time periodically. This year I put them out in a ton of sun and they are making tons of babies that are very distinctly variegated, so pretty and not the boring plant I thought it was all this time.

The maroon-ish Tradescantia zebrina I have seems to get darker in full sun but the grayish-green stripes get lost. When in enough shade to see the lines clearly, the overall color looks faded to me. I'd say this one depends on preference and available locations.

Since plant book #1, most authors wrote, 'variegated plants need more light than non-variegated.'

But, I disagree. To a point

It depends on the plant. Of course, at the moment, I can't think of any examaples except Talinum/Jewel or Opar and variegated palms. Direct sun only burns these plants.
Certain variegated Orchids and Sans pale instead of pronounce creams and yellows.

Let's see...variegated Ficus colors are more pronounced in full/direct sun.

Ivy is another example. A couple Ivy leaves are pure white, yet getting less sun now than during winter and spring.

Dracaenas 'Stripped' do better in lower light..white/cream is vivid..when one Dracaena in particular got more light, reverted to green..

There are other examples, but I've got things to do. Dinner, etc.

Like they say, variegated plants are actually problem or deformed plants.

Pls. tell us the copyright year of this info, as this could be quite old & science has progressed a lot in recent years, especially in some of these areas.

FYI: the Sans markings to which you refer are not regarded as variegations, just markings.

Variegation in a Sans. is very definite looking, let's see if I can find one of my own examples.

See how this variegation is distinctly striped?

Many folks don't actually believe that Toni, that variegated plants are 'deformed'.

From what I read & hear, some folks believe variegation is virus induced, some believe it's part of the characteristics in the plant's DNA, I'm not informed enough to really know, but tend to lean to the DNA answer rather than that of virus.

This is a beautiful coffee table book © 1994. I bought it for the pictures. The author is from England and her credentials are as an author with no mention of any formal scientific education. I've always assumed she correctly related the science part to the best of her knowledge with info available at the time... but who knows? The book is written about outdoor gardening with temperate plants, as mentioned above. I don't know enough about the science to know if the same info applies to tropical plants or not. Feel free to add any modern enlightenment, anyone!

Wiki article on variegation has some similar info and touches on some other types of variegation. I wonder why Sans folks don't refer to the colors as variegation? According to Wiki and dictionary.com, they're variegated.

I don't believe variegation is deformed, an anomaly or induced by virus either.

After reading this thread, I Googled. Most authors start a variegation article by saying, 'variegation can occur for a number of reasons.'

Does anyone really know why plants are variegated? Is it similar to, who came first, the chicken or the egg?

Many variegated plants do need more light than their normally colored counterparts however that does not necessarily mean an intense change such as from shade to direct sun. It could just be a closer location to a light source or a brighter room in the house. I guess that amounts to the same thing but you should get the idea.

Yes, I agree, many variegated plants need brighter, 'not necessarly intense sun,' to keep colors.

On certain occassions, either a plant/s were intentionally set in total shade, or accidently fell behind a shelf w/o my knowledge.
Once discovered, variegation was more colorful than when getting light.

I have two variegated Orchids..Phalaenopsis...one gets natural sun, the second under artificial lights..
The Phal in lower light is more pronounced..the orchid in bright-indirect lost variegation. The sun isn't harsh.

Same with some Philodendrons/Monsteras/Marantas/Stromanthes/Ctentanthes/Stromanths
.
However, all/most plants need light, whether it's dark shade or direct sun. Toni

No one has mentioned the flip-side to this. The best low light plants are usually dark green in color. Examples are Dracaena Janet Craig, Aspidistra, Jade Pothos and Peace Lily.

~Will

Tradescantia spathacea looks much better, with wider, more colorful stripes since I backed it up some into more shade (just AM sun now.)

Can't get Cordyline fruticosa to make that pretty pinkish/purple stripe no matter where I put it.

Still looking for ideal exposure for the tiny pink Syngoniums I dug-up from the yard earlier this year.

In my experience, though, it seems to be the least "interesting"/perceived to be original varieties that take the lowest light.

D. Marginata is a good example - D. Magenta is slightly darker than the basic version and yet seem to need more light. Ditto, Sansverieria Laurentii (with the yellow edged leaves) will take lower light than S. Zeylanica (with the plain green leaves).