MYSTERY PLANT: Mystery Plant can cause problems in waterways
…Our sea-walled garden, the whole land,
is full of weeds, her fairest flowers choked up…
Richard II. Act 3, Scene 4
An ugly situation: England was a mess, and being ravaged from the competition among Richard II and his rivals. In the garden of the Duke of York, the gardener and his servant are talking over the fretful times, and the servant suggests that this garden, so neglected and full of weeds, is metaphorically much like England. I can just imagine the gardener saying to him, “Hey, I’ve been doing the best I can.”
The sad truth is that invasive and persistent weeds are becoming increasingly commonplace at both international and local levels. A tremendous amount of money is spent annually on their control, with varying success. The damage caused by weedy plants in agricultural settings is enormous, and figures heavily into crop yield, both now and in the future, and especially as an effect of climate change.
An unintended consequence of chemical weed control, which seems to be very popular, is that surrounding, “non-target” species are impacted as well, along with the beneficial critters (such as pollinators) associated with them. Introduced, non-native plants are actually taking up more of the landscape than the natives, and many of these are indeed invasive. And, we must remember that not all invasive weeds are on the high ground: there are plenty of aquatic nuisance species. Like this one.
It really is a pretty one, but with a sort of terrible beauty. The stems flop and spread against each other, piling up, branching and forming dense mats of vegetation, and large growths of it may break up and float around in a pond, adding to the population. Flowers are produced single along the stem, with five to six green sepals, topped by five to seven bright yellow petals.
Each flower is capable of producing a small capsule with lots of seeds, but the primary way that this plant spreads is, again, no doubt by vegetative means, the stems breaking apart and forming additional mats. These mats can cause all sorts of problems in ponds and lakes, clogging up canals and waterways, thus hindering water flow, boating, fishing and other recreational activities. And of course, these weeds commonly displace the native aquatic species to the point that the good guys disappear.
Probably the saddest aspect of this aquatic weed business is that most of the plants we seem to be fighting have been introduced, whether unintentionally or not, by humans. One of the complicating factors in the continuing spread of these pests is that frequently, gardeners will not know what it is exactly they are buying from a plant supplier, the supplier not knowing precisely what they are selling.
In the case of our Mystery Plant, there are actually more than one species that can be involved, and they are difficult to distinguish. Every Southeastern state has developed a list of potentially invasive plants, and you might want to investigate this link to find out more information, visit www.se-eppc.org/publications.cfm. And don’t forget that if you need help with plant identifications, consult the nice botanists at your local herbarium.
[Answer: “Water primrose”, Ludwigia peploides (subspecies glabrescens]