Spring PMC Field Day Highlights: Innovation, Restoration, and Lessons from the Field

Story and photos by Alia Webb, Public Affairs Specialist, Davis, California

The Spring Plant Materials Center (PMC) Field Day in Lockeford brought together conservation professionals, researchers, and land managers for a day of hands-on learning and discussion around emerging technologies and restoration practices.

One of the standout demonstrations featured agricultural drone technology presented by Kevin Hill of Parabug and Julia Micheals of Hedgerow Farms and its growing role in conservation. Attendees observed drone seeding and spraying in action, including applications for both agricultural fields and hedgerow plantings. With a capacity of approximately 10 liters (about 24 pounds) per flight, drones offer an efficient way to distribute seed across varied terrain. However, presenters emphasized that proper calibration is essential. By running automated calibration, it is often as simple as measuring output into a bucket so operators can ensure consistent seed distribution throughout the flight. Environmental factors such as wind were also highlighted, as they can significantly affect seed drift and overall accuracy.

Field discussions led by PMC Manager Margeret Smither-Kopperl addressed the challenges of the past growing season. An unusually wet fall created ideal conditions for grass weeds, allowing them to establish early and outcompete native species. This was followed by a hot, dry winter and early spring, further disadvantaging native plants. As a result, many sites saw increased weed pressure and reduced native plant success.

Plant materials research continues to play a critical role in improving restoration outcomes. Trials focused on milkweed species key host plants for monarch butterflies highlighted the importance of early-emerging varieties such as heartleaf and California milkweed. These species help address "phenological mismatch," ensuring that monarchs have access to host plants when they arrive. Researchers also found that container choice significantly impacts survival. Because milkweed roots are fragile and do not form strong root balls, using jiffy pots or similar liners helped maintain root integrity during planting. Additionally, fall planting proved far more successful than spring planting, allowing plants to establish before going dormant and avoiding early-season heat stress.

Native thistle trials challenged common misconceptions about thistles as purely invasive weeds. California's native thistles provide valuable habitat and food resources for pollinators, including butterflies and bees. However, propagation has been difficult due to rapid root growth. Trials showed that while plugs can be used, plants perform better when transplanted early or grown in deeper containers to accommodate root development. As with milkweed, fall planting yielded the best results.

Discussions around cover crops emphasized that outcomes depend heavily on both species selection and management. While flowering plants are often prioritized for pollinators, traditional mixes of small grains and legumes can also provide significant benefits if managed properly. Timing of mowing is especially important, as cutting too early can prevent plants from flowering and reduce habitat value.

Intercropping and soil health were also key topics. Research led in collaboration with UC Davis is evaluating multiple cover crop mixes, including erosion-control and region-specific blends. Over several years, these trials are assessing how plant diversity influences soil health, resource use, and resilience. Early findings suggest that diverse plant mixes can better utilize available resources by complementing one another rather than competing directly.

Additional field observations highlighted practical lessons in restoration. Plug planting, while labor-intensive, can be highly effective when timed correctly even under less-than-ideal conditions. In one case, plugs installed in late spring during an unusually cool season established successfully without irrigation beyond the first summer. Riparian restoration efforts demonstrated that smaller plugs can perform just as well as larger ones when adequate moisture is available, and proper spacing (2-3 feet) allows plants to establish and eventually reduce irrigation needs. These plantings not only improve water quality but also create valuable wildlife habitat, with some species reaching impressive growth in a single season.

Overall, the Spring PMC Field Day underscored the importance of adaptive management, thoughtful selection, and emerging technologies in conservation. From drones to deep-rooted natives, the event highlighted practical strategies for improving restoration success across California's diverse landscapes.

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