Water lilies have floating leaves. There are about 40 species of water lily in the world, plus numerous hybrids and varieties. Some water lily species prefer southerly warmth and are found in temperate and semi-tropical zones, some prefer the cold and are found only in northern Canada and Alaska.
This species, fragrant water lily (Nymphaea odorata), occurs from Puerto Rico to Alaska and from California to Quebec (Kartesz 1999). Its many subspecies and varieties may be found floating in ponds, lakes and sluggish streams just about everywhere in North America.Description
Nephrolepis cordifolia is a wood fern that typically grows in woodland areas. Both fertile and sterile fronds are pinnate, up to 3 feet in length and 3 inches wide. There are many leaflets, or pinnae, ranging from 40-100 mm (1.5 to 4 inches) on each side of the rachis. Each pinna is oblong to lanceolate with an auricle that overlaps rachis. Rhizomes are orange/brown to pale brown with linear scales having hair like tips. Stolons are straw colored and produce small underground tubers. The presence of tubers distinguishes sword fern from the native Nephrolepis exaltata fern. Numerous sori (spore containing structures) are also produced between the leaflet midvein and margin. Dispersal occurs via spores and through the movement of stolons, tubers, and rhizomes.Impacts
The sword fern poses a threat on native species. Through its aggressive spread, sword fern is able to form dense stands and quickly displace native vegetation. Because it is a true fern, it reproduces via spores. Thousands of spores can be produced by one plant and these can be dispersed by wind and water. Spore production occurs year-round in south Florida.
The first step in preventative control of sword fern is to limit planting and removal of existing plants within the landscape. If possible, removal should occur before spores are produced.Cultural
Plant native or non-invasive alternatives. Inform the public to refrain from purchasing, propagating, or planting sword fern due to its ability to escape from cultivation. Avoid transport of spores from one area to the next via people, vehicles and other equipment.Mechanical
Hand pulling can be used to remove some of the fern plants, but the plants will break off, leaving plant parts in the ground from which regrowth will occur. Be sure to dispose of plants properly.Biological
There are no known biological agents for the control of sword fern.Chemical
Plants can be killed with herbicides containing glyphosate. A foliar application of a 1.5% solution provides good control. Follow-up applications are necessary to control plants regrowing from rhizomes and tubers.