Get Your Goat On! Reducing Blackberries and Increasing Native Plants with Controlled Grazing
By Laura Jessup About four years ago, I moved to a sweet old home on 3 1⁄2 acres. Tall pines and giant oaks surround the house, native pink clarkia and yellow madia bloom each summer in the open field, and Oregon grape adds color to the understory in spring. These are hardy native plants able to hold space among the many non-native grasses and forbs introduced over the years. However, in the riparian areas there was just one species that squeezed out nearly everything: Himalayan blackberry, a delicious but pernicious invasive plant that not only out-competes nearly all natives, but also accumulates hazardous wildfire fuel. The fire marshal was appalled. The neighborhood FireWise community was concerned. On nearly two acres, Rubus armeniacus had formed a prickly impenetrable thicket -- twenty feet high in places! Introduced by Luther Burbank in 1885, Himalayan “giant” blackberry has become a giant problem. On our property, these introduced blackberries mangled small madrone trees, pushed down mock orange, covered snowberry and ferns, and shaded out acorn sprouts and pine saplings. It was a sea of blackberry, dry canes becoming deeper and denser as the new growth smothered all plants below. Gone were the native plants that once thrived in the riparian area, and gone were the diverse native pollinators that depended on the native plants. There was not a trace of the native thimbleberry, blackcap raspberry, and salmonberry that once coexisted in harmony with snowberry, vine maple, and mock orange, among others, a balance that allowed for a diverse flora and fauna. The slopes and creek were covered with just one species: blackberry. But this villain of a plant is no match for our heroines -- enter two nannies, retired from a small dairy farm, with a keen appetite for blackberry. Goats are well equipped for eating brush and especially enjoy blackberries. Their prehensile tongues are well suited for eating shrubs, spines, and leaves, making them well adapted for eating thorny blackberry canes. Goats also prefer to browse rather than graze, so instead of grazing on grasses, they focus their eating on leaves and twigs. Researchers in the United States and Europe have found that goats effectively clear vegetation and can improve plant diversity. The key is to balance the number of goats with the rate of plant growth. If the rate of plant removal is lower than the rate of plant growth, then grazing can reduce vegetation without damaging the ecosystem. The critical factors are the number of animals and the time the animals are allowed to graze. For our small farm, we first cut the blackberry thatch. Next, we fenced about an acre of blackberries by building a fence of woven wire and two strands of electric wire to keep the goats in, since goats are notorious escape artists known to jump over, push through, or burrow under fences. Finally, we built a shed so the goats could be safe from predators during the night. Next, we “rescued” two Alpine dairy goats that had been culled from the herd and were destined for the butcher. These ladies promptly set to work. Our two goats happily cleared an acre of robust blackberry regrowth in about a year. They continue to clear blackberry regrowth, but now require additional feed to reduce the grazing pressure on native trees and grasses that we hope will replace the blackberries. Remember, goats will eat just about anything and can quickly kill a tree by stripping the bark and even climbing branches to pull down leaves! For additional feed, we occasionally buy timothy hay; however, my preference is to simply toss into the pasture downed limbs or prunings from trees and bushes around our property. Last winter, we threw into the pasture fruit tree prunings, birch branches, even our dry Christmas tree, and within a week or two the goats had stripped the leaves, twigs, and bark, leaving us with great kindling for the wood stove! To protect native plants, I built hardware-cloth cages around several volunteer snowberry, honeysuckle, Oregon grape, ferns, and wild strawberries. I didn’t cage the volunteer poison oak; although poison oak is a native plant and the birds love the berries, since we have poison oak growing elsewhere I thought it okay if the goats enjoy keeping the population from spreading. Goats love poison oak, too! For the next few years, we’ll need to carefully manage our goat grazing to balance blackberry removal with a healthy ecosystem. Studies of other restoration projects have shown that goats are effective at eliminating blackberry and re-establishing native grasses, and can even improve soil health. Several recent studies show that goat grazing can improve the soil by enriching microbial communities. The goat droppings increase nutrients and beneficial bacteria in the soil. In our restoration project, within about three years the two goats will nearly eliminate the blackberries in their 1-acre pasture. I’ve begun sowing native grasses and caging native shrubs and trees, and when the goats move on to greener pastures, I will plant more native shrubs and forbs to restore a diverse ecosystem. This spring, when the fire marshal inspected our property for wildfire safety, we got a thumbs up! The goats have drastically reduced wildfire fuel on our property, eating not only the blackberries, but also clearing dense brush and low-hanging tree branches. I hope more landowners will begin using controlled grazing as a way to reduce blackberries without herbicides.
The fire marshal mentioned that the City of Ashland would like to use goats but is having trouble finding a goat herder able to assume the responsibility (and liability) of bringing goats to the city. I think that it is just a matter of time before we see goats in Ashland and other cities. The Los Altos Hills County Fire District has had good success with goat grazing; residents appreciated that there was no need for chemicals or bulldozers and enjoyed getting to know their new four-legged neighbors. The neighbors welcomed the goats, and a more diverse flora welcomed diverse pollinators! Laura Jessup is a native plant enthusiast and certified Land Steward. References - Girard-Cartier, C. B., & Kleppel, G. S. (2017). Grazing and the coupling of biodiversity in vascular plant and soil microbial communities. Northeastern Naturalist , 24 (8), 67-85. https://doi.org/10.1656/045.024.0sp806 - Ingham, C. (2014). Himalaya Blackberry (Rubus armeniacus) response to goat browsing and mowing. Invasive Plant Science and Management, 7( 3), 532-539. doi:10.1614/IPSM-D-13-00065.1 - Khatri, R., Karki, U., Bettis, J., & Karki, Y. (2016). Grazing with goats changed the woodland plant-species composition during summer. Professional Agricultural Workers Journal , 4 (174-2016-2189), 1-11. https://ageconsearch.umn.edu/record/253127/ - Kleppel, G., Girard, C.B., Caggiano, S., & LaBarge, E. (2011). Invasive plant control by livestock: from targeted eradication to ecosystem restoration. Ecological Restoration 29 (3), 209-211. https://www.muse.jhu.edu/article/448453 . - Los Altos Hills County Fire District. (n.d.). Goats to the rescue. https://www.lahcfd.org/wp-content/uploads/2019/04/goats-to-rescue-v5.pdf - Mann, Damian. (2019, June 18) Overgrown weeds getting your goat? Medford Mail Tribune. https://mailtribune.com/news/top-stories/medford-council-may-expand-use-of-animals-to -clear-private-property-of-vegetation-invasive-weeds - Moinardeau, C., Mesléard, F., Ramone, H., & Dutoit, T. (2019). Using mechanical clearing and goat grazing for restoring understorey plant diversity of embankments in the Rhône Valley (Southern France). Plant Biosystems-An International Journal Dealing with all Aspects of Plant Biology , 1-11. https://doi.org/10.1080/11263504.2019.1686080 - Salter, M., Macdonald, E., & Richardson, Z. (n.d.). Prescribed goat grazing in urban settings: a pilot study of the legal framework in nine U.S. cities. Council of Educators in Landscape Architecture. https://thecela.org/wp-content/uploads/PRESCRIBED-GOAT-GRAZING-IN-URBAN-S ETTINGS.pdf - USDA (2019). Goat targeted grazing: Examples to study dynamics of targeted grazing for unwanted vegetation management using goats. United States Department of Agriculture Cooperative Extension . https://goats.extension.org/goat-targeted-grazing/