Following hot on the heels of my recent obsession with all things miniature, from roses to pigs, is a budding (sorry) fascination with all things variegated, from cats to caladiums.
This interest was sparked a few decades ago when I had a Siamese cat, and wondered how the coloured ears and feet actually occurred with such precision.
It was back in the days before the internet and I had to go first to the library, which was somewhat thin on the science of coloured points in Oriental cats, and then to the local cat fanciers club, which told me more than I ever wanted to know about why my Pywacket's ears and feet were brown when the rest of him wasn't.
Fortunately, an investigation into variegated plants has been easier, although I have yet to discover why I suddenly like them.
As usual I'm a little behind the times, since variegated plants are now among the more sought-after and collected treasures of garden connoisseurs. There's a certain snob value in something that's marbled, dotted or splashed, rather than merely striped, and if you have a plant with a distinctive formal pattern, even better.
This became clear to me when I found a stunning caladium at the local hardware store. Every now and then this store comes up with something very off-the-wall, which leads me to believe the plant buyer there must be as frothy as I am.
But when I went back later in the week to get one, all the caladiums - green and white, grey and red, pink and green - were gone.
I hurried home to Google them and it took about a minute of looking at all the varieties to form the idea of planting a variegated garden.
I've had caladiums before - two sad little green-and-white house plants that drooped miserably. But I have a shady area in the garden that should be just right for a collection of caladiums, and perhaps a few other variegated plants for definition.
Caladiums are tropical and love shade and humidity. Given the right conditions they grow quite fast, so even if you live in a cooler part of the country you can enjoy them outside in summer, and inside all year provided you don't mistreat them as I obviously did.
About 95 per cent of the world's caladium tubers are produced in Florida and, like Siamese cats, they don't come by those wonderful colours and patterns by accident. Researchers are constantly developing new varieties, although looking at the images on Google, you'd think they'd pretty much covered the spectrum already.
I don't think the following applies to cats, but it goes some way to explain variegation in plants. Most commonly it's a genetic experiment or mistake (depending on your evolutionary point of view) that occasionally appears in nature.
A white variegation is the result of a plant's inability to produce any pigment in that area.
Orange, yellow and light green leaf colours result from less production of the green pigment, chlorophyll, unmasking the orange carotenoid and yellow xanthophyll pigments and allowing them to appear.
Shades of pink, red, and purple are the result of anthocyanin pigments. If produced in sufficient quantities, they can mask even the green chlorophyll.
Variegation can occasionally be the result of a virus infection, producing mosaic or streaked symptoms on leaves and/or petals. Evidently there was a horticultural craze in 17th century Holland for tulips with streaked petals based on virus-infected plants.
There are also plants with silver colours on their leaves, but there are no silver plant pigments. The appropriately named Aluminium Plant has patches of silver on its leaves because the unpigmented upper layer of the leaf is lifted from the layer below.
Some variegations can be unstable, with plants producing all green or all white (albino) shoots or leaves. Obviously, some things are just not meant to be.
Variegated plants often have more exacting environmental needs than the all green members of the species. Some can't tolerate very low light (less chlorophyll for photosynthesis) but, on the other hand, may scorch under bright light (less protective pigmentation).
Less vigour, smaller leaves and increased sensitivity to temperature extremes are other features of variegation. Unless variegation has some adaptive feature, such as attracting pollinators or repelling herbivores, it is a liability that makes variegated plants less likely to successfully compete with all-green plants. The "struggle for existence" in nature eliminates the less adapted.
Could be why the world's not full of naturally occurring stripy, spotty, speckled, splashed plants.