43. Sweet-Fern - Syndicat des producteurs de bleuets du Québec

Wild Blueberry
Production Guide...
in a Context of
Sustainable Development
43. Sweet-Fern
Latin name: Comptonia peregrina (L.) Coulter
French name: La comptonie voyageuse
Sweet-fern is the only species of Comptonia found in North America. It occurs in sandy terrain, often in association with
jack pine. It grows in large dense formations and offers significant competition to blueberry cultivation in places where it
is established. Herbicides are of variable effectiveness against it, which explains why this weed is of such concern to wild
blueberry growers.
DESCRIPTION
Sweet-fern is not a fern but a deciduous shrub, 0.5 to 1.0 m in height, extensively branched and aromatic (Figure 1). Its fernlike leaves are alternate, close, long and narrow with many lobes, distinctively fragrant when crushed. Ecologically it is welladapted to the dry soils of northern regions, where it thrives. For example, its bur-like fruit produces resinous secretions
that protect it from desiccation. Like legumes, it fixes nitrogen from the air. The species propagates especially well on open
ground that has been cleared by fire, for its rhizomes run horizontally under the ground, producing roots and sending up
aerial stems. As with blueberries, mowing or burning a field will stimulate sweet-fern to multiply further.
CONTROL
Hand-pulling of sweet-fern is possible, but must be done before the seeds are dispersed. Gloves should be worn to avoid
injury to the hands.
When sweet-fern is taller than the
blueberries, mowing the upper level
can slow its development provided this
is done before the seeds are released.
Ideally, if there is sufficient regrowth
for such mowing to be done repeatedly
over the summer, the plant’s nutrient
reserves will gradually be exhausted.
This is most effective when the field is
in a growth year.
There is no data showing the long-term
effectiveness of either hand-pulling or
mowing for controlling sweet-fern in
blueberry fields.
Herbicides
Glyphosate and hexazinone, applied in
the growth year, are registered herbicides
against sweet-fern in blueberry production. Their effectiveness varies however.
The herbicides available for controlling
this weed are presented in Leaflet 19
in this series, Pesticides Used in Wild
Blueberry Production.
Figure 1. Infestation of sweet-fern
Source: Suzanne Hardy, Enracinart
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43. Sweet-Fern
COMPLEMENTARY LEAFLETS
15. Integrated Pest Management in Wild Blueberry Production
19. Pesticides Used in Wild Blueberry Production
REFERENCES
Desjardins, È.-C. and R. Néron. 2010. Guide d’identification des alliés et ennemis du bleuet nain : Insectes, maladies et végétaux.
Centre de recherche Les Buissons. p. 152.
Marie-Victorin, Frère. 1995. Flore laurentienne. Troisième édition. Les Presses de l’Université de Montréal. p. 157.
Ministère des Terres et Forêts. 1974. Petite flore forestière du Québec. Éditions France-Amérique. p. 128.
Sampson, K.V. and D.L. McCully. 1990. Weeds of Eastern Canadian Blueberry Fields. Nova Scotia Agricultural College Bookstore.
Truro, Nova Scotia. p. 186.
Yarborough, D. 2001. Cultural Management for Weeds in Wild Blueberries. Fact Sheet No. 252. The University of Maine.
Cooperative Extension. [Online].
http://umaine.edu/blueberries/factsheets/management/cultural-management-for-weeds-in-wild-blueberries/ (Page consulted on
September 15, 2010).
PROJECT COORDINATION
PUBLISHING
Sophie Gagnon, Agronomist,
Coordinator, Agrinova, Alma
Project
Management
Chantale Ferland, M.Sc., Publishing Project Officer, CRAAQ,
Québec
Lyne Lauzon, Publications Coordinator, CRAAQ, Québec
ADAPTATION
Sophie Gagnon, Agronomist,
Coordinator, Agrinova, Alma
Project
TRANSLATION
Management
Rod Willmot, M.A.
REVISION
LAYOUT AND GRAPHIC DESIGN
Danielle Bernier, Agronomist-Weed Scientist, Ministère de
l’Agriculture, des Pêcheries et de l’Alimentation du Québec,
Québec
Sylvie Robitaille, Computer Graphics Technician, CRAAQ,
Québec
Gaétan Chiasson, Agronomist, Development Officer, New
Brunswick Department of Agriculture, Aquaculture and
Fisheries, Bathurst
Laurier Tremblay, Agronomist, Ministère de l’Agriculture,
des Pêcheries et de l’Alimentation du Québec, Bergeronnes
PRODUCED BY
FUNDED BY
Association
des producteurs
de bleuets de
la Côte-Nord
Wild Blueberry Production Guide
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