The Controversy Surrounding Purple Loosestrife 



John Weaver 



M Witc 

 ■^L beaut 



urple loosestrife, or Lythrum salicaria, (Figurel) 



has two things in common with the Wicked 



Witch in Snow White: it is very beautiful (the witch's 



beauty was second only to that of Snow White) and it Is 

 very wicked (the Wicked Witch was — well, a wicked witch 

 and didn't have much choice). Opinions on purple loos- 

 estrife vary: some view it as a harmful non-indigenous spe- 

 cies; to others, it is a beautiful perennial plant. My opinion 

 is that, like the Wicked Witch, purple loosestrife is very ma- 

 ligned and only acting in character. In Europe and Asia, it is 

 a respected citizen of its environment. Only 

 in North America, without its natural en- 

 emies, is it a problem. 



Opinions as to the effects that purple 

 loosestrife has on the environment also vary. 

 A large group of wildlife biologists presently 

 contend that it has an obvious detrimental 

 effect and present the following scenario: 

 purple loosestrife invades natural wetlands 

 and displaces many native plants, such as 

 cattail and sedges. This, in turn, causes an 

 exodus of the herbivores (muskrats and other 

 animals) who eat these plants. Purple loos- 

 estrife has very little nutritious value to most 

 species of wildlife. Many species of birds, in- 

 cluding marsh wrens, least bitterns, ducks, 

 and geese, join the exodus as well. The dis- 

 placement of waterfowl, especially, has raised 

 the concerns of the Department of Interior's 

 U.S. Fish and Wildlife Service. The United 

 States Department of Agriculture (USDA) also 

 recently decided to recognize purple loos- 

 estrife as an agricultural pest on the bases of 

 its presence in a few agricultural crop situa- 

 tions. 



However, not all scientists share this opin- 

 ion. A small group of ecologists, led by Mark 

 G. Anderson, a former graduate student at 

 the University of New Hampshire, argue that 

 the wildlife biologists' scenario may be blown out of pro- 

 portion or is at least lacking strong supportive data. Many 

 people enjoy purple loosestrife just for its beauty. In fact, 

 the first plants noted in New Hampshire (Conway, August 

 1875) probably originated from cultivation. Commercial bee- 



FlGURE I. 



Purple loosestrife 

 (after Bailey, 1916) 



keepers like the plant as well and benefit from it by plac- 

 ing their hives in fields of purple loosestrife in late sum- 

 mer. Most of their preferred hive sites in July and August 

 are near loosestrife because, before goldenrod and asters 

 bloom, many other honey-productive summer flowers have 

 faded. 



The U.S. Fish and Wildlife Service and the Department 

 of Natural Resources (DNR) began an aggressive program to 

 control purple loosestrife, especially in the Midwest, about 

 20 years ago. Their early control methods included the 

 physical removal of plants, mowing and regu- 

 lating water levels in marshes, and the appli- 

 cation of herbicides registered for use in wet- 

 lands. All of these control methods were very 

 labor-intensive and expensive and, in most 

 situations, did not provided a very successful 

 or long-term solution to the problem. 



About ten years ago, some states passed 

 legislation officially recognizing purple loos- 

 estrife as a noxious weed, thus restricting its 

 sale and distribution. However, the new law 

 for many of the states became a "regulatory 

 nightmare," because it applied only to 

 Lythrum salicaria, which could not be distin- 

 guished from L. virgatum or the many cultivars 

 of Lythrum (most of which have resulted from 

 various crosses between these two species). 

 Thus, no one could effectively enforce the 

 ban on loosestrife. Many states consequently 

 broadened their regulations to include all cul- 

 tivars and non-native species of Lythrum so 

 that their previous restrictions on purple loos- 

 estrife could be enforced. (Winged lythrum, 

 or Lythrum alatum, is our only native species 

 of Lythrum.) 



Commercial growers and nurserymen pro- 

 tested, claiming that several of their cultivars 

 were sterile, and that the broad ban on loos- 

 estrife was unjustified and would hurt their 

 business. The experiences of some gardeners seemed to 

 justify their reaction: "Despite the profuse blooms on my 

 jDropmore Purple], I have never seen any seedlings develop 

 around them." But other gardeners had different stories: "A 

 few years ago, 1 purchased several varieties of [loosestrife] . 



AUGUST ■*■ SEPTEMBER 1996 



