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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research Unit » Research » Publications at this Location » Publication #188619
Title: TOLERANCE OF VARIOUS HARDY FERNS TO SELECTED PREEMERGENCE HERBICIDES

Author
item Fain, Glenn
item GILLIAM, CHARLES - AUBURN UNIV
item KEEVER, GARY - AUBURN UNIV

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2006
Publication Date: 1/1/2006
Citation: Fain, G.B., Gilliam, C.H., Keever, G.J. 2006. Tolerance of various hardy ferns to selected preemergence herbicides. HortTechnology 16(4):605-609.

Interpretive Summary: The objective of this study was to determine the effects of selected preemergence herbicides on growth of various hardy fern species. Fern cultivars evaluated were: variegated leatherleaf fern (Arachniodes simplicor 'Variegata'), tassel fern (Polystichum polyblepharum), autumn fern (Dryopteris erythrosora), holly fern (Cyrtomium falcatum ‘Rochfordii’), and southern shield fern (Dryopteris ludoviciana). The least susceptible species to injury was southern shield fern treated with Kansel+. Autumn fern had reduced growth when treated with Ronstar, Snapshot, Pendulum, Aquacap, Rout, Kansel, Ronstar, or RegalStar. Reductions in growth of holly fern were most severe when plants were treated with Snapshot. The most sensitive fern to herbicides evaluated in 2004 was leatherleaf with reduced growth with 6 of the 10 herbicides tested. In the 2004 study the greatest reduction in growth of autumn fern was observed with Kansel+, Ronstar, and RegalStar. While all herbicides tested appeared to be safe on southern shield fern especially in the 2004 study, species such as the tassel fern and holly fern appear to be more sensitive. RegalKade proved to be a safe herbicide for all species tested in both 2004 and 2005. In the 2005 all plants from all treatments were considered marketable by the end of the study.

Technical Abstract: Hardy ferns are widely grown for use in the landscape. The 1998 National Agricultural Statistics Services census of horticulture reported production of hardy/garden ferns at 3,107,000 containers from over 1200 nurseries. Weeds in container-grown plants are unsightly, reduce growth of plants and contribute to the spread of weeds to other parts of the nursery and landscape. There is little research on herbicide use in hardy ferns, and herbicides that are labeled for container production are not labeled for use on hardy ferns. Studies were conducted to evaluate the tolerance of variegated leatherleaf fern (Arachniodes simplicor 'Variegata'), tassel fern (Polystichum polyblepharum), autumn fern (Dryopteris erythrosora), holly fern (Cyrtomium falcatum ‘Rochfordii’), and southern shield fern (Dryopteris ludoviciana), to applications of selected preemergence applied herbicides. Pendulum® Aquacap™ (38.7% a.i. pendimethalin), Barricade® (40.7% a.i. prodiamine), and Gallery® (75% a.i. isoxaben). Granular applied herbicides were Pendulum® (2% a.i. pendimethalin), RegalKade® (0.5% a.i. prodiamine), RegalStar® (1% a.i. oxadiazon plus 0.2% a.i. prodiamine), Rout® (2% a.i. oxyfuorfen plus 1% a.i. oryzalin), Snapshot™ (2% a.i. trifluralin plus 0.5% a.i. isoxaben), Ronstar® (2% a.i. oxadiazon), and Kansel+® (2% a.i. oxadiazon plus 1.25% a.i. pendamethalin). The greatest reduction in growth of autumn fern was observed with Kansel+®, Ronstar®, and RegalStar® all three of which contain oxadiazon as an active ingredient. Reductions in growth of holly fern were most severe when plants were treated with Snapshot® resulting in a 41.5 and 54% decrease in frond length and frond number respectively. There were also reductions in number of fronds when treated with Pendulum®, RegalStar®, Rout®, and Kansel+®. There were no reductions in number of fronds on tassel fern with any of the herbicides tested. However, there were reductions in frond length for 6 of the 10 herbicides evaluated. The most sensitive fern to herbicides evaluated in 2004 was leatherleaf with reductions in frond length and number of fronds with 6 of the 10 herbicides tested. While all herbicides tested on southern shield fern appeared to be safe especially in the 2004 study, species such as the tassel fern and holly fern appear to be more sensitive. RegalKade® proved to be a safe herbicide for all species tested in both 2004 and 2005. In 2005 all plants from all treatments were considered marketable by the end of the study. However there was significant visual injury observed on the holly fern treated with Gallery at 60 and 90 DAT which might reduce their early marketability.