Plant a Geiger counter in your garden.

Nature has always served as Mankind’s early warning system — the canary in the coal mine, and possibly, the spiderwort in the nuclear plower plant. You may not think of garden plants as particularly active, but many have unique “behaviors” that are somewhat entertaining, and at times even useful. The ephemeral blooms of Tradescantia, also known as spiderwort, among other fun names, have special sensitivities: the tri-petal flowers open and close based on the weather and light levels; when it is really hot, the flowers close, but on an overcast or rainy day, they seem to glow. But the most exciting Tradescantia trick is that it will change flower colors when exposed to low levels of radiation, among other pollutants. It is fairly easy to find bloggers exclaiming the virtues of Tradescantia in detecting radiation (some groups even guerilla plant Tradescantia around nuclear power plants). They claim that Tradescantia flowers generally turn from blue to pink when exposed to low levels of radiation. This claim is both over- and under-inclusive. First, there are about 70 Tradescantia species native to North America, with flowers in several, naturally-occurring colors: blue, purple, white, pink, magenta, white with purple stripes, and even more varieties native to other parts of the world. Some are just natually pink. But it is true: scientists have discovered that cells of the tiny hairs on the stamen of the Tradescantia ohiensis KU 7 clone turn from blue to pink when exposed to various forms of radiation in the laboratory, and other scientists have found that other species of Tradescantia display this chameleon trait in the wild too.

blue Tradescantia

Tradescantia close up

Tradescantia close up


I have seen a clump of flowers on my own Tradescantia hybrid suddenly turn from purple to pink, even while others on the same plant remained purple. Curious. However, this “warning system” is of limited practical use. It turns out that the flower is sensitive to many common pollutants, like car exhaust and cigarette smoke too. So seeing my blue spiderwort turn pink means … the city air is polluted; which is about as useful as seeing through the sweat dripping from your brow that the spiderwort has closed it petals to tell you it is hot outside. Nonetheless, the plant’s ability to detect radiation will no doubt be of some use in the lab and perhaps one day in the field. It is one more area where Nature’s genius can provide answers for Mankind.

Note:  Tradescantia is another one of those plants with fun common names, like spiderwort and snotweed; but given it’s usefulness to science, I think it deserves a more respectful moniker than “snotweed.”

Blue and lime green spider lily, Tradescantia hybrid

Blue and lime green spider lily, Tradescantia hybrid

Pink flower cluster on purple Tradescantia


One thought on “Plant a Geiger counter in your garden.

  1. LOL, have you been out poking around in my garden? I have spiderwort of all shades that migrated over from my next door neighbor’s yard many years ago. It’s also out in the alley. I have light purple, blue-purple (looks blue in bright sun but it’s quite purplish in shade), deep purple, BRIGHT PINK (with pink hairs), pale pink, striped pink and striped “blue”, pure white, orchid– an intermediate between pink and purple… it’s all there. I don’t think this is a radiation mutation so much as the fact that I have SO MUCH of it that’s taken off through the years that it’s probably a mix that she planted and all the genetics were there for these colors to express naturally. And because there are lots of bees that happily gather pollen in the spiderwort garden, they also help with the creation and spread of these diverse shades. However they happen, the colors are a lovely sight during the bloom peak, which is almost always at Easter time here in N. Texas. They’re quite lovely as (DISTANT!) companions to Irises, as the bloom times overlap. I have tall bearded and dwarf bearded Irises in several colors, mostly purples and peachy-pinks and yellows. There are also some Muscari (grape hyacinth) that grow wild. We let them go, because they also look great with the spiderwort– a low carpet of slender green leaves and tiny purple clusters underlying tall stalks of spiderwort and colorful Irises. Just, wow! It looks like a pastel picture when everything’s going. But it is invasive, and you really have to keep it under control or it will take over!

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