Invasive plants can have severe negative consequences on native biodiversity and ecosystem functioning. Controlling such species is a key component of ecological restoration, and weed management is an important consideration when developing restoration plans. This includes removing invasives as part of site preparation as well as continued management of weeds following seeding or outplanting.

Native seed sown into areas dominated by invasive plants generally perform very poorly [1] and in many cases fail to establish entirely. In order to increase restoration success, perform weed management at least one season prior to seeding or replanting in order to kill existing plants and prevent existing plants from going to seed [2]. Initiating weed management two years before revegetation activities is even more ideal, as this allows the practitioner to deplete the weed seed bank as well. However, initiating management this early may be logistically and financially infeasible.

Many conventional weed management strategies (e.g. grazing, herbicide application and prescribed fire) suggest targeting a particular point in the life cycle of the plant (e.g., the seedling). Keep in mind that many populations of invasive plants do not enter life stages at the same time. For example, spraying a patch of seedings will likely not yield complete eradication because some of the plants will not yet be in the seedling stage. Multiple management events within a single season can address this obstacle. Moreover, integrated pest management (IPM) strategies, where mutually supporting approaches (e.g., herbicide, mechanical, burning, competition) are used in concert to target weeds, tend to be most successful in the long term and can increase restoration success [2]. 

Weed Identification Resources

• California Invasive Plant Council
• Cal-IPC Plant Profiles
• California Noxious Weeds
• UC Weed Research & Information Center
• Invasive Species ID Cards for EDRR

Weed Management Resources

• WeedCut: Methods for Managing Weeds in Wildlands
• Calflora Weed Manager: Resources, Applications and Techniques
• Invasive Plants of California’s Wildlands
• Weed Worker’s Handbook
• WHIPPET Tool
• Best Practices for Non-chemical Weed

References

When carefully planned and implemented, targeted grazing can be a highly effective pre-restoration tool for reducing invasive plant populations and preparing a site for native plant establishment [1]. Grazing is especially useful for targeting palatable, non-toxic weeds during growth stages when they are most susceptible. This can be a highly cost-effective option for treating large areas [2], particularly when affordable fencing and infrastructure are available.

In addition to reducing invasive species, well-managed grazing can improve site conditions by enhancing soil aeration, promoting nutrient cycling, and creating microsite variability that can support native seedling establishment [3]. The success of targeted grazing depends on several factors: the species and number of grazing animals, timing and duration of grazing, and the specific conditions of the site [4]. In appropriate locations, grazing may be a long-term weed suppression strategy [5]. While grazing can be a powerful tool for large-scale weed control, it is most effective as part of a long-term integrated management plan and requires adequate infrastructure, including water access, fencing, and ongoing monitoring to avoid unintended impacts on native species.

Resources

• UC Rangelands: A Research and Information Center
• Combining Active Restoration and Targeted Grazing to Establish Native Plants and Reduce Fuel Loads in Invaded Ecosystems
• A Summary of Livestock Grazing Systems Used on Rangelands in the Western United States and Canada
• Grazing as a Tool for California Grassland Conservation
• WeedCUT | Grazing

References

In California, prescribed fire is increasingly recognized as a valuable tool for ecological restoration and land stewardship. When applied appropriately, it can help reduce the buildup of flammable fuels, control invasive species, and create more favorable conditions for native plant species. Prescribed burns can also enhance diversity and improve long-term resilience in grasslands [1], oak woodlands [2], forests [3], and other fire-adapted landscapes, as well as enhance restoration success. Using fire as part of restoration planning can improve site conditions before planting and help suppress weeds that compete with young native plants [4]. However, prescribed fire is not appropriate for every ecosystem, and in some cases, it can disrupt or damage native plant communities. 

It is important to acknowledge that Indigenous peoples in California have been using fire as a land stewardship practice for thousands of years. These cultural burning traditions are distinct from modern prescribed fire in their purpose, scale, and approach, but they provide similar ecological benefits: supporting biodiversity, enhancing habitat, and maintaining the health and resilience of fire-adapted ecosystems [5].

Prescribed burning in California typically takes two forms: broadcast burns, which cover larger areas under controlled conditions, and pile burns, which target smaller accumulations of brush or woody material to reduce fuel loads [6]. The choice of method depends on site conditions, restoration goals, and safety considerations. Successful implementation requires collaboration between landowners, ecologists, fire professionals, and agencies such as CAL FIRE and local air quality districts. Burn plans must carefully outline objectives, timing, weather windows, and contingency measures, with necessary permits secured well in advance. Joining local prescribed burn associations (PBAs) or working with experienced practitioners can help ensure burns are conducted safely, effectively, and in alignment with ecological goals.

Resources

• UC ANR Fire Network | Prescribed Fire Benefits
• CAL FIRE | Prescribed Fire
• California Prescribed Burn Associations (PBAs)
• California’s Strategic Plan for Expanding the Use of Beneficial Fire
• California Air Resources Board | Prescribed Fire
• US Forest Service | Tribal and Indigenous Fire Tradition

References

1. Keeley, J. E., Klinger, R. C., Brennan, T. J., Lawson, D. M., La Grange, J., & Berg, K. N. (2023). A decade‐long study of repeated prescription burning in California native grassland restoration. Restoration Ecology, 31(7), e13939. https://doi.org/10.1111/rec.13939
2. Hankins, D. L. (2015). Restoring indigenous prescribed fires to California oak woodlands. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: US Department of Agriculture, Forest Service, Pacific Southwest Research Station. PDF
3. Keifer, M., Stephenson, N. L., & Manley, J. (2000). Prescribed fire as the minimum tool for wilderness forest and fire regime restoration: A case study from the Sierra Nevada, California. PDF
4. Moyes, A. B., Witter, M. S., & Gamon, J. A. (2005). Restoration of native perennials in a California annual grassland after prescribed spring burning and solarization. Restoration Ecology, 13(4), 659-666. https://doi.org/10.1111/j.1526-100X.2005.00084.x
5. Martinez, D. J., Seraphin, B., Marks-Block, T., Nelson, P., & Vinyeta, K. (2023). Indigenous fire futures: Anticolonial approaches to shifting fire relations in California. Environment and Society, 14(1), 142-161. https://doi.org/10.3167/ares.2023.140109
6. Rau A. What is? Prescribed Burn. Corvallis (OR): Northwest Fire Science Consortium; c2020. PDF

Tilling, disking, or soil ripping can be a useful tool for site preparation, but it comes with trade-offs that should be carefully considered. Tilling can promote native seedling establishment by loosening compacted soils [1], improving aeration, and creating small-scale variation in soil conditions that benefit seed germination and growth [2]. It can also help incorporate seed into the soil surface, reducing seed loss from wind or runoff. In addition, tilling can be strategically timed to kill off early flushes of weeds that germinate before native seed sowing, helping to reduce weed competition during critical establishment phases [3].

However, tilling also introduces disturbance that can stimulate invasive weed germination and spread [4]. It can contribute to soil compaction from equipment traffic, disrupt soil structure, and lead to the loss of valuable soil carbon. Disking may also create deep furrows that bury seeds too deeply for successful emergence. In certain cases (such as sites with toxic soils, poor drainage, or in post-mining substrates) tilling may be beneficial [5]. If using this method, aim for a till depth between 6 and 12 inches.

References

1. Curtis, M. J., & Claassen, V. P. (2009). Regenerating topsoil functionality in four drastically disturbed soil types by compost incorporation. Restoration Ecology, 17(1), 24-32. https://doi.org/10.1111/j.1526-100X.2007.00329.x
2. Montalvo, A. M., McMillan, P. A., & Allen, E. B. (2002). The relative importance of seeding method, soil ripping, and soil variables on seeding success. Restoration Ecology, 10(1), 52-67. https://doi.org/10.1046/j.1526-100X.2002.10106.x
3. Stromberg, M. R., D’antonio, C. M., Young, T. P., Wirka, J., & Kephart, P. R. (2007). California grassland restoration. California grasslands: ecology and management. University of California Press, Berkeley, 254-280. PDF
4. Bauman, Jenise M., et al. "Plant community development following restoration treatments on a legacy reclaimed mine site." Ecological Engineering 83 (2015): 521-528. https://doi.org/10.1016/j.ecoleng.2015.06.023
5. Olson, N. C., Gulliver, J. S., Nieber, J. L., & Kayhanian, M. (2013). Remediation to improve infiltration into compact soils. Journal of Environmental Management, 117, 85-95. https://doi.org/10.1016/j.jenvman.2012.10.057

Restoration outcomes are heavily influenced by soil conditions, including factors such as nutrient availability, pH levels, texture, and the composition of soil microbial communities [1]. Restoration efforts are often undertaken at sites where soils have been disturbed or altered, and in the most severe cases, soils may be contaminated or inhospitable to plant growth. To address these challenges, various soil amendments—such as organic matter, compost, and biochar—can be applied to improve soil structure, enhance nutrient content, and promote healthier soil microbial communities, ultimately supporting better plant establishment and growth [2]. It is important to note that these treatments may not be required at many sites, and in some cases could have unintended negative consequences.

When using amendments in restoration, the first step is to thoroughly assess the soil conditions at the site and identify any barriers to plant establishment, such as nutrient deficiencies, compaction, contamination, or poor drainage. In some cases, conducting soil testing can be an important tool for diagnosing these issues and identifying appropriate soil manipulations. 

Resources

• CDFA | Recommended List of Soil Labs
• Guidelines for Using Non-Traditional Soil Additives
• CNPS | Site and Soil
• CNPS | Soil 101
• CNPS | Mulching Basics
• Tree of Life Nursery | The Basic 1-2-3 on Soils for Native Plants

References

1. Heneghan, L., Miller, S. P., Baer, S., Callaham Jr, M. A., Montgomery, J., Pavao‐Zuckerman, M., Rhoades, C.C. & Richardson, S. (2008). Integrating soil ecological knowledge into restoration management. Restoration Ecology, 16(4), 608-617. https://doi.org/10.1111/j.1526-100X.2008.00477.x
2. Ohsowski, B. M., Klironomos, J. N., Dunfield, K. E., & Hart, M. M. (2012). The potential of soil amendments for restoring severely disturbed grasslands. Applied Soil Ecology, 60, 77-83. https://doi.org/10.1016/j.apsoil.2012.02.006

Microbial inoculation has become an increasingly important tool in ecological restoration [1], particularly in degraded soils where native microbial communities have been lost or disrupted. Healthy soils host diverse communities of bacteria, fungi, and other microorganisms that play key roles in nutrient cycling, organic matter decomposition, soil structure maintenance, and plant health. In many disturbed or heavily altered environments, such as mine lands, compacted soils, or areas subjected to repeated tilling or chemical use, these microbial communities are diminished or absent, which can limit native plant establishment and long-term restoration success. Reintroducing beneficial microbes, such as mycorrhizal fungi or nitrogen-fixing bacteria, can help jump-start soil processes, improve nutrient availability, and increase plant survival and growth, ultimately enhancing restoration success [2]. These soil biota can also improve plant drought tolerance [3] and may be especially important for climate-smart restoration [1].

Microbial inoculation methods vary depending on site conditions and restoration goals, with increasing recognition that native soil biota are often better suited for ecological restoration than commercial inoculants developed for agriculture [4]. Practitioners may introduce specific microbial groups, such as mycorrhizal fungi or nitrogen-fixing rhizobia, or apply whole soil inoculum collected from nearby native plant communities to restore a diverse soil microbiome. Inoculum can be applied directly to the field in thin layers or added to individual planting holes. Alternatively, nursery-grown plants can be inoculated prior to outplanting to promote early establishment of beneficial microbial associations. 

Resources

• UN Decade on Ecosystem Restoration | Soil Biodiversity: Contributions and Threats
• Practical Applications of Soil Microbiota to Improve Ecosystem Restoration: Current Knowledge and Future Directions
• A Practical Guide to Inoculation with Arbuscular Mycorrhizal Fungi in Ecological Restoration
• Selection of Mycorrhizal Fungi for California Native Plants
• Tree of Life Nursery | Mycorrhizae

References

1. Valliere, J. M., Wong, W. S., Nevill, P. G., Zhong, H., & Dixon, K. W. (2020). Preparing for the worst: Utilizing stress‐tolerant soil microbial communities to aid ecological restoration in the Anthropocene. Ecological Solutions and Evidence, 1(2), e12027. https://doi.org/10.1002/2688-8319.12027
2. Wubs, E. R., Van der Putten, W. H., Bosch, M., & Bezemer, T. M. (2016). Soil inoculation steers restoration of terrestrial ecosystems. Nature Plants, 2(8), 1-5. https://doi.org/10.1038/nplants.2016.107
3. Valliere, J. M., & Allen, E. B. (2016). Interactive effects of nitrogen deposition and drought-stress on plant-soil feedbacks of Artemisia californica seedlings. Plant and Soil, 403, 277-290. https://doi.org/10.1007/s11104-015-2776-y
4. Wong, W. S., Ruscalleda-Alvarez, J., Yong, J. W., Stevens, J. C., Valliere, J. M., & Veneklaas, E. J. (2024). Limited efficacy of a commercial microbial inoculant for improving growth and physiological performance of native plant species. Conservation Physiology, 12(1), coae037. https://doi.org/10.1093/conphys/coae037