OLD WORLD CLIMBING FERN

(Lygodium microphyllum)

Background: Old World climbing fern is an invasive, non-native vine that is rapidly spreading in Florida. It devastates native plant communities by smothering understory and canopy trees, altering fire ecology, and creating thick mats of plant material on the ground. Land managers and property owners should be constantly vigilant for this weed, and its elimination should be a land management priority.

How to Identify: Fern with dark brown, wiry rhizomes and climbing, twining fronds to 90 ft long; main rachis (leaf stalk) wiry, stemlike. Leafy branches off main rachis once compound, oblongish in outline, 2-5 in long. Leaflets usually unlobed, stalked, and without hairs; fertile leaflets fringed with tiny lobes of enrolled leaf tissue covering the sporangia (spore-containing structures) along the leaf margin.

 

Where to Look: Most likely to occur in central and south Florida. Reported from all counties south of Sarasota, and in Highlands, Martin and Hillsborough Counties. Because it reproduces by millions of spores spread by wind and other physical carriers, new infestations can arise great distances from existing populations. Most commonly occurs in moist habitats, but also grows in shallow water and dry areas. Cypress wetlands, Everglades tree islands, floodplain, hammocks, roadside ditches and disturbed corridors are common habitats. Young plants are often found on moist portions (moss collars) of tree buttresses.

 

CONTROL GUIDELINES FOR LAND MANAGERS

How to Control: Cutting vines will result in death of the vines above the cut location, but will not kill the lower portion of the plant. Regrowth will occur after physical removal (hand-pulling) or burning. Flooding does not kill established vines but seems to prevent germination of spores on flooded soils. Use of heavy equipment has limited value because site access is often limited, and equipment can disturb soils and non-target vegetation and transport spores to new locations. Control requires application of herbicide. Herbicides should only be applied by those knowledgeable in the use. Contact the IFAS Pesticide Information Office, 352/392-4721, for additional information on pesticide applicator training . See IFAS Publication SP242, "Control of Non-native Plants in Natural Areas of Florida" for information on applying herbicides in natural areas. Always read the entire herbicide label and follow its instructions. The herbicide and method of application used will depend on age, extent, and location of population as follows:

Small or low-growing populations - thoroughly spray-to-wet foliage with 1.25% Garlon 4TM (4 pt/acre), 0.6% Roundup ProTM (5 pt/acre), 1.0% RodeoTM (7.5 pt/acre), or 2.5 oz EscortTM per 100 gal water (1.0 oz/acre). Only RodeoTM can be used over water. A non-ionic surfactant may be used with Garlon 4TM and is essential with RodeoTM and Escort.

Vines climbing high into trees - apply PathfinderTM herbicide to the vines in a 12-inch band four to five ft above the ground or cut vines and treat lower portions as described above. PathfinderTM has not always been effective when applied to Old World climbing fern in this manner, perhaps because the vines were not actively growing. Apply herbicides any time of year, but for most consistent results, apply when plants are actively growing and not slowed by environmental stress. Apply during drier seasons to allow use of herbicides not labeled for use over water, and when reduced foliage may improve access and visibility.

RodeoTM and RoundupTM are broad-spectrum herbicides, which are absorbed through the leaves but not the roots or bark of trees. Garlon 4TM and PathfinderTM can be absorbed through the bark of trees. Applications of Garlon 4TM and PathfinderTM to vines growing on trees should be done with appropriate care. Most broad leaf plants are susceptible to Garlon 4TM and PathfinderTM but many grasses are relatively tolerant and will recover if damaged. Many grasses and woody species are tolerant to EscortTM, but control may take up to six months to be evident. Use knowledge of herbicide characteristics to minimize non-target damage by careful selection and application of herbicide, and make case-by-case evaluation of acceptable non-target damage levels.

Removal of dead climbing fern can be costly, but dead material inhibits growth of desirable vegetation, and provides a medium for germination of remaining spores, a trellis for growth of new plants, and a fuel for fire. Removing thick rachis mats can accelerate native plant regrowth. Care should be taken in any procedure to avoid spreading spores. Pulled material should be bagged prior to transport, and disposed of so as not to spread viable material. Mulching or composting are not recommended because spores may remain viable for long periods of time.

Report all new occurrences in natural areas and provide herbarium voucher specimens as described on the FLEPPC website:

http://www.fleppc.org/database/data_intro.htm

For photographs see:  Identification & Biology of Non-Native Plants in Florida’s Natural Areas (1998, University of Florida, 800/226-1764). For more information about Old World climbing fern contact Amy Ferriter, FLEPPC Climbing Fern Task Force, 561/687-6097, aferrite@sfwmd.gov.