I've often wondered—ok, maybe not often, but sometimes for sure—why petunias are sticky. It's not even a sap thing; it's just right there on their leaves, some kind of invisible sticky goo. Why?

It turns out petunias might be a bit...carnivorous. And it's not just petunias. Potatoes, heath and the seeds—yes, seeds—of shepherd's purse are, in the words of Mark Chase, Keeper of the Jodrell Laboratory at the Royal Botanic Gardens at Kew in England, "subtly carnivorous."

Venus fly traps and pitcher plants capture and digest insects in an obvious, in-your-face sort of way. But those sticky, sneaky petunias...they lure insects to an adhesive death and, when the insect falls to the soil, dead, the petunia's roots absorb the nutrients of decay.

Mr. Chase suggests that "What plants are doing is much more sophisticated than we ever imagined." Read more about the secret lives of plants here.