2 INTRODUCTION 



of plant varies considerably, depending on local circumstances, i 

 Bulrushes, though generally desirable, become so dense and domi- 

 nant in some localities that they need to be reduced. In the South 

 and some other regions, cattails compete too successfully with desir- 

 able plants in duck marshes, yet in the Northwest cattail marshes 

 furnish useful nesting cover for redheads, ruddies, and other 

 waterfowl. Similarly, though phragmites and needlerush have no 

 food value for waterfowl they provide useful protective cover in 

 some flooded feeding sites. In the latter type of situation, weed 

 control can consist of opening up dense stands of the plants instead 

 of trying to eliminate them. 



Some weedy species are practically nationwide in distribution, 

 whereas others have more restricted range. Cattails, phragmites, 

 spatterdock, and willows are examples of wide-ranging marsh 

 weeds. Waterchestnut is at present a problem only in the North- 

 east; saltcedar is confined mainly to the Southwest; and several 

 troublesome plants such as alligatorweed, giant cutgrass, maiden- 

 cane, needlerush, sawgrass, waterhyacinth, and waterlettuce are 

 limited largely or entirely to the South. 



The control of floating or floating-leaf plants such as water- 

 hyacinth, waterlilies, and spatterdock is discussed in this circular, 

 but submerged aquatics are excluded because their suppression is 

 primarily the concern of fishpond management and a fishery leaflet^ 

 on the subject is available. Objectionable trees and shrubs of 

 waterfowl habitat are discussed in the final chapter on Woody 

 Weeds. 



ACKNOWLEDGMENTS 



Information in this booklet has been compiled from many sources. 

 Much of it has come from studies or operations by the Branches of 

 Wildlife Research and Wildlife Refuges of the Bureau of Sport 

 Fisheries and Wildlife, U. S. Fish and Wildlife Service, cited in the 

 text as FWS, and much has been drawn from tests conducted by 

 State Federal Aid programs and by the Agricultural Research 

 Service in its cooperative studies with the Bureau of Reclamation. 

 Plant names, both common and scientific, have been based largely 

 on Neil Hotchkiss's Checklist of Marsh and Aquatic Plants of the 

 United States, FWS Wildlife Leaflet 210, 1950. 



> Information on duck-food usefulness of various marsh and aquatic plants, as well as on their distribu- 

 tion, propagation, and environmental requirements, is given in Food of Game Ducks in the United States 

 and Canada, by A. C. Martin and F. M. Uhler, FLsh and Wildlife Service Research Report 30, 1951. 



» Control of Aquatic Plants in Ponds and Lakes. Eugene W. Surber. FWS Fishery Leaflet 344, 1949. 



