A few weeks ago I received an email question from a customer who had purchased seed from us. "How long does Drosera intermedia and D. aliciae live?" he wanted to know. I was stumped. Usually with species such as these, growers and hobbyists keep reproducing plants such as sundews from leaf and root cuttings, seed, and dividing larger clumps, but the lifespan of an individual plant such as a rosetted sundew grown from seed is something I've never really thought much about, and I've never done any experiments to find out how long an individual plant could live if grown from seed.
I can tell you this: Apparently in the wild temperate sundews do have a limited lifetime. While a teenager living on the New Jersey shore, two of the largest D. rotundifolias I ever found (one in Tuckerton, the other in Manahawkin) measured five to six inches across (12 to 15 cm)........but both were dead! As I told a friend who was with me at the Tuckerton site, exclaiming at the size of the dead plant, I concluded it must have "died of old age". Usually round leaf sundews average about three inches (7.5 cm) in diameter although they can be much larger in some areas. But how many years old the plants were I had no idea.
Of course, many carnivorous plants can "live forever". We know this from the species and hybrids in cultivation, some dating back to the Victorian Age. We still grow Nepenthes x dyeriana, the original plant that won a gold metal at the Chelsea Flower Show in the year 1900, and a number of other tropical pitcher plants that entered cultivation or were created by horticulturalists over a century ago. We reproduce them through stem cuttings (and sometimes in tissue culture). We still have Sarracenia x willisii, which also dates back to the late 1800s, since American pitcher plants can be divided over and over and over again. Each time it seems the divisions start life anew, as though coming into birth for the first time. At California Carnivores we grow descendants of my original Sarracenia purpurea ssp. purpurea that I've had since I was sixteen years old, (I'm sixty-two now!) but where the original plant is, if even still alive, I have no idea. We keep it alive by dividing older clumps and growing new ones from seed.
There are certainly pitcher plants of many varieties that are indeed very old in the wild. Stewart McPherson, in his co-written book Sarraceniaceae of South America, has photos of a massive clump of Heliamphora chimantensis several meters across. Although this giant clump produces many flowers, no seedlings anywhere around the clump could be found, and he has assumed the whole plant is one gigantic clone that has spread from offshoots. He guesses it must be "centuries old". This is also probably true of Darlingtonia californica cobra plants in California and Oregon, endless yards (meters) of plants spreading through stolon growth down seeps and streams, quite possibly dating back for centuries. The same can be said for massive clonal clumps of Sarracenia in the wild.
Bob Ziemer, editor of the Carnivorous Plant Newsletter, has been growing a Dionaea he first bought at a Woolworth's store in the mid-1950s. Of course he also has reproduced the plant from leaf cuttings, keeping it going all these decades.
The oldest Venus flytrap I've heard about in the wild comes from a conversation I had back in 2004, with a woman whose family has owned property near Wilmington, North Carolina since the late 1800s. Many flytraps grow on the property, but there was one individual plant that grows near the base of a Longleaf Pine that is exceptionally large. She claims it was first pointed out to the family way back in 1904 by her great grandfather, because it was such a large plant. When she called me in 2004 she and members of her family were having a 100 year birthday party for the plant, feeding it some tasty bugs! Who knows how old the plant was when her ancestor first noticed it, but the plant is certainly much old than a century.
I happen to live among some of the oldest plants in the world, since I live in the redwood country of northern California. There's a giant Sequoia about 100 feet (30 meters) from my house that is estimated to be nearly 2000 years old. Can an individual carnivorous plant live that long? Very doubtful, but in cultivation, and propagating through division and stem cuttings....who knows? If humans survive that long, perhaps in the year 2216 A.D. maybe some of the plants in your collection will still be growing.......maybe even in huge glasshouses on the planet Mars?