“Dirty Dozen” Invasive Species – Japanese Climbing Fern

Continuing our monthly series of invasive species articles – this week we look at the first of the “Dirty Dozen”.  The Dirty Dozen are the 12 worst, most problematic, established invasive species within the Six Rivers CISMA – as decided by the members of the Six Rivers CISMA.  This month we look at the Japanese Climbing Fern (Lygodium japanicum).

 

Define Invasive Species: must have all of the following –

• Is non-native to the area, in our case northwest Florida
• Introduced by humans, whether intentional or accidental
• Causing either an environmental or economic problem, possibly both

Define “Dirty Dozen” Species:

These are species that are well established within the CISMA and are considered, by members of the CISMA, to be one of the top 12 worst problems in our area.

 

Native Range:

Japanese Climbing Fern is from eastern Asia.

 

Introduction:

The plant was introduced by humans intentionally in the 1930s as an ornamental plant.

 

EDDMapS currently list 28,649 records of this plant.  Most are in the coastal states of the southeastern U.S.

Within our CISMA there are 3148 records.  This is CERTAINLY underreported.

 

Description:

Japanese Climbing Fern is vine that grows from rhizomes below the ground.  The stems and rhizomes are very thin and wire like.  The leaves can be flat and finger-like to “lacey” and “feather-like” and are opposite on the vine.  The broader leaves carry the sporangia housing the spores.  The spores are very tiny and can be carried by the wind and by your clothes.  The vines will develop massive thick mats covering fences, sides of buildings, and much of the native vegetation in the area.  In winter the vines, and leaves, appear brown and dead, but they are not.  It grows well in sun or shade, damp areas that have been disturbed but grows just as well in areas that have not been disturbed.

 

Issues and Impacts:

This plant forms massive dense mats that can completely cover all native vegetation in the area.  This matting can reduce sunlight to existing plants and reduce their ability to germinate seedlings.  The vines are known to grow as high as 90 feet into the tree canopy.  The plant has been a problem for the timber industry trying to collect pine straw for sale.  It was listed as a Florida Noxious Weed in 1999.

 

Management:

Hand removal, or any other means of mechanical removal, has not been effective.

Burning does kill the above ground biomass, but the below ground biomass usually returns the plant.

Puccinia lygodii, a rust found on many species of Lygodium, may be a biological control.  Studies on this continue.

Chemical treating with a 2-3% solution of Glyphosate has been effective.

Any management of this plant should be done in the late summer/early fall when the spores are not present.

 

For more information on this EDRR species, contact your local extension office.

 

References

Japanese Climbing Fern, University of Florida IFAS Center for Aquatic and Invasive Plants

https://plants-archive.ifas.ufl.edu/plant-directory/lygodium-japonicum/

 

Early Detection and Distribution Mapping System (EDDMapS)

https://www.eddmaps.org/

 

Six Rivers CISMA

https://www.floridainvasives.org/sixrivers/