- Author: Christine Casey
The Haven was created in 2009: we celebrate our 15th anniversary this year. I joined the garden in 2012 and was tasked with creating an outreach and education program. Tours, social media pages, classes, and this blog soon followed. This will end in June, when my position at the Haven is being eliminated.
I've enjoyed introducing so many of you to bees, providing information about gardens and bees, and answering your questions. Working with our amazing volunteers and donors has been extraordinary.
This blog is a short reflection on what I've learned from this work. Look for additional posts throughout May that will provide more bee gardening information, including resources beyond the Haven.
Some random thoughts:
- Children often arrive at the Haven afraid of bees but leave excited to learn more. If you are an adult with children in your life, take advantage of their curiosity to teach them about the natural world. Events like the UC Davis Biodiversity Museum Day are a great place to start.
- You're probably overwatering your garden. Irrigation information for California gardens is here.
- Go on as many garden tours as you can. There's always more to learn.
- There's a lot of bad gardening information on social media. Stick with reputable sources like universities, government agencies, and good independent garden centers.
- In shared public spaces, please don't litter or use a speakerphone.
- Small public gardens and museums are passionate about what we do but operate with minimal resources. Please give what you can and understand that we can't always meet every need or provide all the programs we'd like to.
- Support local nurseries and plant sales.
- Pick up after your dog and leash them in areas where it's required.
- Leave some bare soil for ground-nesting bees.
- There's always room for one more plant.
- Author: Christine Casey
I've written previously about the Haven's research on bees and gardens. This work included a look at bee preferences for common California landscape plants and work to help growers and landscapers provide the healthiest plants for bees.
Studies on bee plant preferences were described in this blog post, and the first year's results (2022) of our current project developing bee sampling methods for growers and landscapers was described in this post.
The current project is an evaluation of a common insect sampling method, timed counts, with a novel method called snapshot counts. As the name suggests, the snapshot methods uses several quick counts rather than one longer timed count to assess the number of bees choosing a plant. Our goal was to see if the faster snapshot method could provide bee counts with accuracy similar to the widely used timed count method.
The speed of the snapshot method could allow it to be included with other routine insect sampling done by growers and landscapers. This would provide a way to assess the relative attractiveness of a nursery or landscape plant mix to bees, allowing for both accurate plant recommendations and targeting of bee-compatible pest management.
Trials took place at locations in San Diego County, the center of California's nursery industry.
While the average number of bees observed per plant differs between the two methods, the pattern of preference is the same for both (Fig. 2). This is confirmed by regression analysis (Fig. 3), which found a strong correlation between the two methods
Our goal was not to determine the absolute number of bees expected on a plant, as that will vary with location, season, and weather. Rather, we wanted to understand which plants are more likely to be chosen within a plant mix. Growers can then compare new plant varieties to those with known attractiveness to determine how they'll fit into a bee garden.
- Author: Christine Casey
- Author: Lea Corkidi
Regular Haven visitors notice that we frequently change our planting. It's one of the joys of gardening -- there are always new plants to try and experiment with. At the Haven, research on new plants and methods for bee gardens is essential to our educational mission.
Previous posts have reported on our work with bee plant preferences, with an emphasis on low-water plants. Our colleagues at UC Cooperative Extension in Southern California have done similar work for that part of the state. Previous blog posts have covered research with mulch, plant color, and water; all are important components of a healthy bee garden.
But all this is for naught if it isn't put into practice. So our current work is to create tools for the California horticulture industry to educate employees and customers about bee garden best practices based on this research. The first step in this work is development of an efficient sampling method so growers, landscapers, and public gardens can easily assess the bee-attractiveness of new plants as they come on the market. This will allow these plants to be marketed correctly, and will also help growers to target bee-friendly pest management.
In our attractiveness studies the Southern CA team used timed counts, while the Northern CA team used a snapshot count method (1). This technique consists of 20 second quick counts of every plant that is repeated three times in succession rather than a single 3-minute timed count. The snapshot count is faster to complete and more readily worked into the day of an otherwise busy nursery employee.
The purpose of this study was to calculate the relative net precision (RNP) of each bee counting method at a wholesale nursery (Fallbrook, CA) and a public garden site (Encinitas, CA) in San Diego County. RNP is calculated as shown below and is a way to assess sampling efficiency by balancing precision and sampling cost (2).
RNP = [1/(cost x Rv)] x 100, where Rv = (SE/mean) x 100
Plants in full bloom were sampled weekly for at least 4 weeks using both methods. Bees were counted as honey bees or other bees as this distinction is easy for an untrained observer; only honey bee data is reported here. At both locations, we saw a larger absolute number of bees with the snapshot method, but the trend of most attractive to least attractive was the same for both methods (Figures 1 and 2). We are most interested in this trend rather than the absolute number, which is expected to vary between locations. Additionally, regression analysis shows that the two counting methods are strongly correlated (Figure 3).
Finally, we saw differences between the RNP values calculated for the two sampling methods, with higher RNP for the snapshot method at both locations (Table 1). Higher RNP means greater sampling efficiency (2).
A second year of study will begin in April at additional sites to confirm these findings. We look forward to providing the California green industry with a useful tool for supporting pollinator gardens.
References
1. Garbuzov and Ratnieks. 2014. Functional Ecology 28: 364-374.
2. Buntin pp 99-115 in Handbook of Sampling Methods for Arthropods in Agriculture. CRC Press, Boca Raton, FL. 1994.
- Author: Christine Casey
I don't know about you, but all the rain and cold weather we're experiencing in Northern California have left me especially eager for this year's gardening season to begin. And if learning more about bees and gardens is something you'd like to do this year, we've got a class for you! We're offering all classes as either remote or in-person. Both methods include videos to view at your leisure; there's additional hands-on instruction with the in-person classes.
All in-person classes take place at the Haven on the UC Davis campus. Class fees support the Haven and our programs.
2023 classes:
I Planted a Bee Garden: Now What?
April 1, 2023 9am to 10:30am
Instructor: Christine Casey, Ph.D., UC Davis Department of Entomology and Nematology
Many California gardeners are removing their water-hungry turf and replacing it with lower-water plants that provide food and habitat for bees and other animals. But if all you know about garden maintenance is how to start the lawnmower, deciding what to plant and learning how to maintain it can be daunting.
Aimed at beginning bee gardeners, this class will cover the basics of turf conversion and weed control along with plant selection for bees and other pollinators. We'll also cover maintenance of a turf yard compared to planted borders. The in-person class includes hands-on practice with gardening techniques and a tour of the Haven's plants.
Remote class registration ($25 fee): https://registration.ucdavis.edu/Item/Details/939
In-person class registration ($40 fee): https://registration.ucdavis.edu/Item/Details/940
Advanced Bee Gardening
April 22, 2023 9am to 10:30am
Instructor: Christine Casey, Ph.D., UC Davis Department of Entomology and Nematology
This class is for experienced gardeners who want to better support bees in their gardens. We'll discuss garden design and plant selection based on bee biology as well as how to encourage insect natural enemies to keep bee gardens pesticide-free. We'll also learn about some of the latest research on bees and gardens and how to incorporate this into your garden. The in-person class will conclude with a tour of the Haven for a hands-on look at plants and bees.
Remote class registration ($25 fee): https://registration.ucdavis.edu/Item/Details/941
In-person class registration ($40 fee): https://registration.ucdavis.edu/Item/Details/942
Collecting Bees Through Photos
April 1, 2023 11:30am to 1pm
Instructor: Christine Casey, Ph.D., UC Davis Department of Entomology and Nematology
Bees are fascinating animals, and many people are intrigued by the idea of having their own bee collection for closer observation. An effective way to ‘collect' bees without harm is by making a bee photo album. We'll start with an overview of bee anatomy and classification and learn how to distinguish bees from other insects. We'll then look at key features of common bees that can be used to identify them in flight. The class will finish outdoors for hands-on experience observing, identifying, and photographing bees.
Remote class registration ($25 fee): https://registration.ucdavis.edu/Item/Details/937
In-person class registration ($40 fee): https://registration.ucdavis.edu/Item/Details/938
- Author: Christine Casey
As we move into the hottest, driest part of the summer, many of our gardens are looking a bit worn out. It's certainly easier to stay inside where it's cool and put garden tasks off until the fall.
But the bees are still out there doing their work to bring us food and create habitat for wildlife. What are the plant options for California gardens that will stand up to the heat with little water (all these plants are rated ‘low' in WUCOLS) and be loved by bees?
One great choice is our native California aster, Symphyotrichum chilense. Unlike asters native to the eastern US and Europe, which need regular water in California, this one thrives on low water. Shown here are the cultivars, 'Purple Haze' and 'Point St. George'.
'Purple Haze' is about 2 feet tall, while 'Point St. George' grows low to the ground. The former has deeper purple flowers than in typical for this species. Both need full sun to light shade and will spread (a lot!) to cover an area. Consider yourself warned when choosing an area to plant these in.
In our studies of bee plant preference at UC Davis we found our native aster to be one of the most attractive plants to California native bees. The late summer flowers are a critical source of nectar and pollen at a time when not a lot is blooming.
The flowers age from white to rust in later summer and provide fall color in the garden into winter.
Finally, for intense late summer color, nothing beats California fuchsia, Epilobium canum. There are numerous cultivars available, but my favorite is ‘Catalina', which reaches about 3 feet tall including flowers. California fuchsia will grow in sun or shade but blooms best in full sun. As with the aster, this plant spreads over time, making it a great filler in areas bounded by paths, buildings, or roads. These serve as barriers to keep it contained, while the plant can take the hot conditions often found in these spots.
Plant all three this fall for a show next summer!