South Dakota Grassland Coalition

By David Ollila

Using funds from a Sustainable Agriculture Research & Education (SARE) Grant along with financial support from the USDI – BLM’s Belle Fourche, SD Field Office, we conducted a targeted grazing exercise on an invader weed species known as Dalmation toadflax. SDSU Extension, USDI-BLM, SDGFP and Doug and Carol Pavel (local producers with grazing experience) cooperated in the project. Our goals included the following:
1) determine the effectiveness of timed grazing on Dalmation toadflax infestations;
2) develop planning protocols to make the grazing application “scalable”; and
3) learn and identify logistical considerations to successfully apply a grazing treatment.

Dalmation toadflax [Linaria dalmatica (L.) Mill.] is an introduced, invasive, deep-rooted perennial forb, growing up to three feet tall. It can spread by seed or lateral roots. The overall form of the plant is narrow and up-right, with multiple stems growing from a single woody base. Snapdragon-type yellow flowers are found along the stalk of each stem. Mature plants can produce up to 500,000 seeds which remain viable in the soil for up to 10 years. The leaves are pale green, waxy-rubbery, dense, alternate, and heart-shaped; the upper leaves clasp the stem. It contains a white latex fluid which can be “off putting” to cattle and wildlife. Good range management with a diverse and healthy native plant community will help prevent the spread of toadflax since it is most competitive in sparsely vegetated monoculture areas. Chemical control of toadflax can be difficult. The waxy leaves make it necessary to add an oil-based or silicon surfactant to the herbicide mix. Biological control methods such as stem weevils and targeted grazing with sheep/goats can be used to suppress and reduce infestations.

In preparation for the targeted grazing project, a portable solar/battery energizer and electric fencing system was acquired and 25 yearling Rambouillet ewes without lambs were trained to respect the fence boundaries. A slatted side 24’ stock trail-er provided portable housing and nightly containment if weather or predation posed a threat. Connected to the stock trailer was “common area of 12-8’ sheep panels and included a floated water tank which was served by a 250 gallon transfer tank on a trailer. The “naïve” sheep (who had never grazed Dalmation toadflax) with an average weight of 140 lbs were introduced to an infested allotted area on May 22nd.

The results of the project were similar to others who have conducted targeted grazing activities. This effort met our objectives with the understanding that a “trained herd” can be developed to effectively graze Dalmation Toadflax. The portable electric fence system allows for specific areas to be targeted. By addressing the logistics, targeted grazing could be economically feasible if scaled up to a longer targeted grazing duration and to a larger band of ewes that would support the employment of a Herder and dogs. The herder and dogs would concentrate the sheep on the infested area and provide protection from predation.

Tours and explanation of this project, its limitations and potential applications were provided to participants of the SD Professional’s Range Camp and also the Grassfed Exchange tour to Northwest South Dakota. The presentations have created additional dialogue with public range managers as well as ranchers to conduct larger target grazing activities.

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