Weeds of Wednesday: Worst of Worst

Invasive pest plant, Oslo Riverfront Conservation Area

Old world climbing fern (Lygodium microphyllum) makes air potato (Dioscorea bulbifera) look docile.  Beware if you see a fern climbing in your yard, shown above along with air potato and cattley guava (Psidium littorale), yet another invasive pest plant. Like all ferns, old world climbing fern reproduces via spores. However, one frond (or “vine”) can be up to 90′ long.

Address the problem immediately and especially before the distinctive fertile leaflets begin to form …

The “fringe” along the edges of fertile leaflets is enrolled leaf tissue that protects the reproductive parts (sporangia). Spores are borne by water and by wind. About 80% of the spores are thought to be viable and last up to 2 years. The spores do require moisture to germinate but will so in sun or shade.

Also note the black, wirey midrib (rachis). Sometimes, a forbidding rachis mat multiple feet deep forms as fronds grow up atop other fronds.

Dr. Stephen Enloe, Associate Professor, UF/IFAS Center for Aquatic & Invasive Plants, describes it as “one of the greatest invasive plant problems in Florida”. It is capable of smothering other plants,  has overtaken many tree islands in the Everglades, and is on the Federal and the Florida Noxious Weed Lists.

Jane Schnee (Class of 2010), a board member of the Friends of the St. Sebastian River (FOSSR), has been documenting its recent and significant spread in the Sebastian area particularly along the Sebastian River. It is out of control and has overwhelmed native vegetation including at this riverfront property shown below where the FOSSR has been conducting volunteer work days …

Thanks to the efforts of volunteers including Diane LaRue (Class of 2012) , Jean “JJ” Romano (Class of 2013), and Susan Warmer (Class of 2006 ) the old world climbing fern infestations at ORCA have been treated with herbicide.