By Dr. Robert Thorson

Someone’s idea of beauty has escaped from a private home, sneaked up behind me, and bit me where it hurts, my wallet.

I’m not referring to the 4-foot-long spiked iguana that went missing after escaping from a private home last summer in East Lyme. Instead, I mean the spread of aquatic plants from private homes and the enormous burden this places on ecosystems and government budgets.

According to The Nature Conservancy, “Invasive species have contributed directly to the decline of 42 percent of the threatened and endangered species in the United States,” and the “annual cost to the United States economy is estimated at $120 billion a year.”

A large part of this cost is caused by aquatic plants spread by the flooding of backyard gardens, by the dumping of containers such as aquariums and minnow buckets, and by stowaways on recreational boats.

A few weeks ago, I spoke to members of the Connecticut Federation of Lakes in Jewitt City. There, I picked up a copy of “Connecticut’s Invasive Aquatic and Wetland Identification Guide,” by Gregory Bugbee and Martha Balfour, and published by the Connecticut Agricultural Experiment Station. This well-designed and scientifically useful handout contains 37 large-format, heavy-duty pages with color photographs illustrating naturally evolved plant species that are choking public waterways.

I have long known that invasive aquatic species are a major problem. What I had failed to appreciate before last week was that 15 of the 22 species listed in Connecticut as “invasive and potentially invasive aquatic plants” are dispersed by water gardening. In other words, this is an example of private pleasure causing public pain.

Water gardening is a huge industry, especially for those with the land, money and time to create their own backyard Edens. It’s also a huge problem. The International Water Gardening Society maintains a list of species listed as noxious weeds by federal and state regulators, ranging from Aeschynomene indica to Zizania aquatica, many of which are still being sold. Apparently, two beautiful invasives on Connecticut’s list – the water hyacinth and water lettuce – are still legal to buy, trade, sell and plant wherever.

The relative value of one plant over another is not the issue. The issue is what belongs where. For example, a modernist Picasso in an exhibit of impressionist Monet; a march by Sousa on a musical program featuring Brahms; and a feathery frond of Eurasian milfoil next to lily pads on one of our ponds are equally out of place. Neither the Picasso nor the Sousa will take over the gallery or the auditorium. But an out-of-place aquatic species can run amok until it overwhelms long-established ecosystems.

Just ask Dave Arzt and Bill Merson, shoreline property owners at Crystal Lake in Ellington and leaders of its amazing voluntary lake association. A few years ago, they realized that variable-leaved milfoil (an escaped aquarium plant) was choking the life out of their lake and hurting town recreation and property values. They applied for state help, which was refused on budgetary grounds. Eventually, local residents coughed up $67,000 of their money to pay for some private party’s mistake.

Last July, I had a more personal encounter with the power of invasive plants. I had joined a nature hike to the Great Meadows National Wildlife Refuge in Concord, Mass. There, and within the last few years, much of the vast wetland’s surface has been taken over by the water chestnut, purple loosestrife and water lotus, all beautiful plants that probably escaped from a backyard garden.

How nice it is to live in the land of the free. Free milfoil, free water lotus, free water hyacinths, free iguanas … free except for the cost.