At first glance, giant reeds wouldn’t seem to be the stuff of dreams — or nightmares — but that’s how things are shaping up in a debate over using an invasive species as a biofuel source.

The giant reed, which is about as rugged and tough as bittersweet, the noxious weed that is the bane of gardeners’ existence throughout New England, is nearly impossible to get rid of once it has started growing. And growing. And growing.

Children and unschooled gardeners often wax sentimental about bittersweet, which can be harvested in fall for centerpieces and wreathes from the first frost through Christmas. But no sensible people mention the plant fondly at a garden club meeting or a gathering of master horticulturists, unless they want to see a group of ordinarily amiable and peaceable tillers turn into a lynch mob.

The problem, of course, is that the vine is virtually immortal and endless once it weasels its way into the garden, hedge or wetlands. It twists through the surrounding foliage, using other plants as convenient architecture to enable its spread, choking off saplings, stretching and snaking through whole habitats in no time.

Giant reed — Arundo donax — has become the new bittersweet, at least among some of those preoccupied with the search for suitable vegetation for biofuel. A recent EPA decision — still pending final approval — to encourage deliberate cultivation of the reed for biofuel has scientists, professional horticulturists, farmers and backyard gardeners up in arms.

They know that the invasive reed — considered one of the top 100 worst invasive weeds in the world — will spread like wildfire if it’s deliberately planted. Actually it has the potential to range uncontrollably even if no one is trying to increase its acreage and cultivation.

The European Union is funding a project to introduce the giant reed, considered a high-yielding, nonfood plant, as a biofuel source. The reed is an environmentally friendly and cost-effective crop with such promise that it could become, the EU claims, “the champion of biomass crops.”

And there was no lack of investor support for a recently proposed Florida biofuel plantation and plant, also using giant reed. Its energy has been sold even before the facility has been built. But some scientists are warning that giant reed growth could encroach upon and endanger the nearby Everglades.

The reed is already out of control in Texas and California, as well as parts of the southern Atlantic seaboard. It has the potential to spread throughout most of the United States, although in New England it is more common to see Phragmites australis, another invasive that has clogged waterways and overwhelmed wetlands.

The problem with the deliberate production of an invasive like giant reed is, in a sense, keeping it from running wild with its underground propagation that moves the population on and on and on. When many plants are chopped down or crops threshed, the seeds are broadcast by wind, carried off by birds or transported on work clothes and boots, enabling them to transport seed far away from the original site — distant enough, perhaps, to become an invader in nearby fields, yards, crops or parks.

By this means — the scattering of seed far and wide — plants rooted in one spot manage for all practical purposes to achieve mobility and the expansion of territory or range — a neat trick, if you appreciate evolutionary cleverness.

But there are other ways to accomplish the same ends, and giant reed employs one in particular, the use of rhizomes and a seemingly endless maze of subterranean tendrils, that are an abomination to try to eliminate. Ever.

Giant reed, native to India, has traveled all the way to North America, swallowing up wetlands throughout the South. It could grow widely in Maine, but it is less immediately problematic in New England than in states with warmer climates more akin to its native regions.

The reed can grow up to 30 feet tall — that’s two to three times the size of phragmites, which also has become one gravely dreaded presence in the landscape from Connecticut north to Maine.

Because giant reed (or giant cane) grows very quickly and prolifically and can reach a towering height, there has been a lot of interest in using it to generate a new biofuel source crop that the federal government is offering to subsidize.

Already, companies have sprouted up in Oregon, Florida and North Carolina, planting it for just this purpose. But the characteristics that make it ideal as a biofuel crop are the same traits that classify it as a worrisome invasive species for gardeners and conservationists who are alert to potential threats to rivers and other waterways. They are wary of its use now and 10 years down the line.

Giant reed has been placed on noxious weed lists in Texas, California, Colorado and Nevada, and has been noted as either invasive or a serious risk in New Mexico, Alabama and South Carolina.

In June, as part of its annual weed risk assessment, the U.S. Department of Agriculture concluded with very high certainty that giant reed is a high-risk species, noting that it is a “highly invasive grass” and a “serious environmental weed.” The estimate of the damage the reed causes in the U.S. runs into millions of dollars annually.

What makes the debate so interesting regarding the use of this bamboo-like reed, which formerly was employed largely in the production of flutes and whistles, is that it is a microcosm of issues dogging green energy projects generally — namely, that they employ methods that are often unreliable and that involve tinkering with nature, a dicey proposition at best. Growing plants for fuels at the risk of food production or biodiversity suddenly makes an ingenious strategy a lot less appealing.

The cost of our continuing diminished biodiversity might be too high for the planet and us. Natural history archives are filled with examples of failures of slick ideas to fine-tune nature and solve so-called problems we encountered there. The introduction of a plant from Asia to America ushered in its own difficulties; now we may be choosing to multiply the risk.

It might be easier to get people to agree to turn off or unplug one light in their homes — permanently. That alone would save millions of dollars in energy costs. It might even pay for some large-scale ventures to get giant reed under control.

North Cairn can be contacted at 791-6325 or at:

ncairn@pressherald.com