It is early spring. Snow patches still abound in shady areas. On a walk through the woods you suddenly smell it. Skunk!! Or so you think. It may not be that striped, furry creature, but rather, one of the earliest spring harbingers, a skunk cabbage.

This unusual plant, Symplocarpus foetidus, is commonly found in marshy wetlands throughout our area and is, in fact, one of the indicator plants that are used to ecologically and legally define wetlands.

This plant belongs to a large group of plants related to lilies and includes many common houseplants such as dumbcane, caladiums, philodendrons, and voodoo lilies. In particular, skunk cabbage is a member of the aroid lilies, a group of plants having two unusual characteristics in common: thermogenesis (heat generation) and putrid smelling flowers!

During the summer, the large leaves of skunk cabbage convert carbon dioxide in the air to sugars that are then converted to starch and stored in the fleshy root. In late winter the root, acting like a furnace, uses this stored material as an energy source to heat the flowering shoot that emerges first, usually before the snow is gone. This can raise the temperature of the plant more than 50 degrees F above the temperature of the surrounding air causing the snow to melt! Why? The heat is thought to serve two purposes: it melts the snow so that the flower is fully exposed for fertilization and also causes volatilization of the compounds that produce the stinky smell. In tropical relatives of skunk cabbage, e.g. the voodoo lily, this smell is akin to that of rotting meat. This attracts flies which are the pollinators of the plant, thus insuring cross-pollination and fertilization. The species, therefore, continues.

Unlike its tropical relatives however, the skunk cabbage does not seem to attract pollinators, mainly because it is still quite cold and few insects are present. Although it is possible that beetles pollinate the skunk cabbage, this is not certain. Nevertheless, the skunk cabbage lives on. So something out there must find it alluring!

How Bitter that Sweet!
By Carol K. Anthony

Bittersweet, that so lovely but dangerous plant, is threatening, as never before, the woodlands that make New England so famous. In the fall, when the leaves are off the trees, the green and yellow Bittersweet leaves remain visible, along with large clusters of its beautifully vivid red and orange berries.

Why is this beguiling climbing vine so dangerous? On the one hand people say its seeds feed birds, however, I have never personally seen any birds near them. Perhaps they save them up for a rainy day, when there is nothing else to eat. In some languages (German for instance) Bittersweet is also called the "tree strangler." This is one plant species that, left to grow unchecked, kills its host, whether it be a honeysuckle or lilac bush, or an oak, pine, hickory, ash, or even the thorny hawthorn tree. It is totally indiscriminate in what it chooses to overrun, and can often be seen running along telephone pole guy wires and telephone lines. When it grows unchecked in a woodland, the entire woodland soon becomes a hopeless tangle of dead trees that appear to be alive only because the tops are so full of Bittersweet.

It is hard to imagine how so beautiful a plant could be such a villain, especially when its first tendrils reach upward to connect with a tree's branch, or when it winds itself in such a lovely way around the trunk of a young tree. Even on first noticing it we do not readily realize that as the tree grows, the vines tighten and thicken gradually to cut a 1/4 inch and then a 1/2 inch deep groove around the trunk, or branch, or twig. As the main feeder vines thicken to the size of one's wrist, they throw off dozens of tough shoots that reach up to the branches; as the tree grows taller, the branches remain firmly anchored by these shoots to the ground; at first they are pulled down, then literally ripped off. If the vine climbs up on a young tree, the top of the tree is simply pulled down into a tighter and tighter arc until it breaks the trunk off. Where these vines have ringed a trunk, the tree breaks off in high winds. While the vines are pretty at first, as they course up a tree, the entire area around the trees eventually becomes an unkempt, dense tangle of impenetrable vines–a total eyesore.

The Bittersweet plant occurs in New England in two species. The one described here is of the climbing species. The other is a non-climbing member of the nightshade family. The climbing species comes in two varieties, the oriental and the native, with both being equally dangerous to the trees. Both have orange and red berries; they are distinguished only by one's having round leaves and the other's having heart-shaped leaves. The oriental variety came from Japan and was first planted in New England as an ornamental vine.

During most of the year Bittersweet grows unnoticed, incorporated into the foliage of the trees and shrubs it climbs. As mentioned before, we notice it in fall because its leaves remain after the leaves of the host trees have fallen off; its presence in the tree gives the tree the appearance of being still in full leaf. In a woods full of Bittersweet, the dead gray tops of the trees can be seen. In days when our suburban areas were still farms, farmers kept Bittersweet stamped out. Wherever these farms have given way to suburbia's growth, Bittersweet often grows unchecked.

Worse, many of today's suburbanites, not knowing of the bitter consequences of allowing this "sweet" and pretty looking plant to grow, have even planted it.

It is my experience that once you "see" Bittersweet, it is so widespread that you begin to feel alarmed, if you are a tree lover. For example, in making a short trip around my own area, I noticed it along large stretches of Route 2 in Acton and Concord, along Route 27 between Sudbury Center and Wayland, and in considerable density along Route 117 from Stow Center to Maynard. Many woodland areas are affected, as for example, the hillside of the Captain Sargent public land in Stow. I saw it in three large spruce trees that the town had planted at the end of the Town Building parking lot. Across the street, behind a private house on the corner of Routes 62 and 117, two fresh Bittersweet tendrils had reached up into the base limbs of a beautiful Linden tree. Walking along one of Stow's beautiful lanes known for its large trees, I saw that Bittersweet had jumped from the top of a heavily infested pine over into the top of a magnificent 100 foot tall ash tree. I noticed it also in one of Framingham's most beautiful sections, along many parts of Edmands Road and Grove Street. One need only step outside one's door, it seems, to see it.

What can be done about this problem? Tree specialists say that using anti-brush sprays may kill the nearby host trees if these sprays get on their foliage, or get into their roots. Cutting the base of the vines immediately relieves the tops of the trees, but the roots also need to be pulled up if the vine is not to come back with new shoots. The other remedy is to cut them back repeatedly. In older days the State Agricultural Agencies had funds to patrol, kill, and remove this kind of obnoxious plant. Perhaps it is time to renew this kind of interest on a state-wide level, in view of the fact that one day, perhaps not too long from now, our New England fall tourist season could be affected.

Stow Conservation Trust Webmaster