Driving south on Hwy. 54 towards Lake of the Ozarks two years ago in May, I first saw it--big stands of Princess Tree in full bloom on the roadside. This fast-growing species, Paulownia tomentosa, covered in pretty purple flowers each spring, is native to China and is a documented exotic invasive plant in the warmer climates of Louisiana, Alabama and Mississippi. I first learned of Princess Tree from Arbor Day pamphlets that arrived in our mail in the late 1980s, circulated in an effort to encourage homeowners to plant trees, any trees, to provide shade. The flowers are pretty, almost like a purple Catalpa flower, and bloom on long stalks as the large ovoid green leaves come out to provide shade.
During my tenure in the Southeast Missouri Lowlands, I encountered Princess Tree in a lawn setting, planted surely because it's pretty and, again, fast-growing. The climate in the Bootheel ten years ago was reminiscent of Western Kentucky and Northern Arkansas, what with slightly less cruel winters, warmer temperatures and more rain than in the Osage River basin. As has been reported for several years now, the growing seasons and USDA planting maps have shifted north: folks in St. Louis can now grow camellias outside, friends in New Orleans are growing papayas, and the warmer climate has allowed me to grow kale year round. Not only have the gardening maps shifted due to warmer weather, but now a new group of southern exotic species are creating a foothold in the Ozarks. The warmer temperatures and milder winters have not just encouraged Princess Tree to explode around Lake of the Ozarks, seemingly overnight, but also the ornamental Pampas grass, the scourge of South Louisiana swamps, and Miscanthus, a common ornamental that is now invading glades around Branson.
I don't know how Princess Tree and Pampas grass with its huge white plume and vicious blades arrived in the Ozarks, but I see them frequently on roadsides. Just as I blinked one year and found an entire woodland filled with bush honeysuckle to a point that nothing else exists there, these southern invasive species seem to be thriving in what was once a too cold climate for them. I realize roadsides are not necessarily high quality ecosystems to begin with, but they can serve as vectors into intact systems. With so many exotic invasive species already in Missouri, I don't know how our ecosystems can deal with any more. But new ones are here and doing quite well.