This year will be a World Bee Day like no other. Created by the United Nations to raise awareness about pollinators, this event is celebrated on the birthday of Anton Janša, a pioneer of modern beekeeping. 

The focus this year is on healthy beekeeping as a way to recognize the impact of coronavirus on beekeepers, and by extension, our food supply.

Want to join in the celebration? Here are some ideas:

• The World Bee Day web page has links to activities and events, including online events
• Closer to home, support a local beekeeper by purchasing their honey and other hive products
• Start watching bees in your own garden to learn more about them and appreciate their activity. Check out our YouTube video for an introduction to bee watching.
• Add bee-supporting plants to your garden. These low-water plants do well in central California.

Squash bee, Peponapis pruinosa (left), and honey bee, Apis mellifera (right), in a zucchini flower. The native squash bee and non-native honey bee both pollinate this crop.

Nicknamed the teddy bear bee, a male valley carpenter bee, Xylocopa varipuncta, peeks out of his nest in an old log

Blooming flowers at the Haven. A variety of pollen and nectar sources help bees stay healthy.

It's the first week of spring at the Haven and our plants are starting to look their best. For those of you who cannot make it to the garden this week, here's a brief tour of what's going on. For those who can make it, I've included some of the bees to look for.

The garden is currently open, although the cities of Davis and Sacramento are now recommending shelter-in-place. If this expands to other areas or becomes mandatory, the garden will close. Check our web page for the latest information.

Now blooming at the Haven:

Ceanothus, many species. For more detail on this genus, see this previous post. 

Western redbud, Cercis occidentalis. This plant provides bright pink flowers early in the year, while leafcutter bees use its foliage for nest construction throughout the summer. This California native needs full sun and little to no summer water. It grows slowly, so it's worth buying a larger size for your own garden. It may be fed on by the redhumped caterpillar; damage occurs towards the end of the season so control is not needed.

Redbud leaves used in a leaf cutter bee nest

Redhumped caterpillars on redbud

Brandegee's sage, Salvia brandegii. This is a long-blooming California native sage. As you can see from the photo, which shows one plant, it can get quite large. Flowering from late January through May, pair it with the summer blooming native Cleveland sage (Salvia clevelandii) for season-long bloom. It also needs full sun and low summer water.

Bladderpod, Isomeris arborea. This is another long-blooming California native. It is at its peak in the spring, but will produce some flowers year-round. Our single plant is about 6 feet by 6 feet. Needs full sun and little to no summer water. 

Firecracker penstemon, Penstemon eatonii. This bright red California native is used more by hummingbirds than bees, and adds a jolt of color to the early spring garden. It's soon to be followed by the foothill penstemon, a bee favorite. The firecracker penstemon can take part shade and will re-bloom if given some water after the first flush of flowers. Like most of our native penstemons, it will go dormant in the heat of the summer, at which point watering should stop.

Bees to look for this week include honey bees and the blacktailed bumble bee, Bombus melanopygus. The latter seems to like the Brandegee's sage, so look for it there.

Blacktailed bumble bee, Bombus melanopygus, male on Brandegee's sage

UPDATE March 17, 2020

Due to coronavirus restrictions, all programs at the Haven have been canceled through May. The September pruning class remains open for registration. We will reschedule the spring classes if possible. Thank you for your understanding.

I'm excited to announce our 2020 class schedule at the Haven, which includes old favorites as well as a new class. Continual learning and experimentation are at the core of what gardeners do, and I hope these offerings will help you expand your knowledge and success as a bee gardener. I'll be the instructor for all classes. 

First up is our popular Planting the Bee Garden class. Bee pollination brings us much of our food and supports most of our wild plants. Interest in helping bee pollinators has never been greater, but what can you do in your own garden to make sure it is bee friendly? We'll review the basics of bee biology as a foundation for understanding how garden design and plant selection can be optimized for bees.

We'll also learn about some of the latest research on bees and gardens and how to incorporate this into your garden. The class will conclude with a tour of the Haven for a hands-on look at plants and bees. Registration includes light breakfast and snacks and course handouts.

This class is being offered twice; content is the same each time. April 25, 8am to 11am, register here. May 16, 8am to 11am, register here.  

Returning from its initial offering last year is Bee Watching for Beginners. Observing and identifying live bees can be challenging. If you'd like to become more adept at identifying the bees in your garden, this is the class for you. We'll start with an overview of bee anatomy 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 in the Haven for hands-on experience observing and identifying bees. Interested students will have the opportunity to use a microscope for closer examination of bee structure.

April 25, 12pm to 3pm, register here.  

The final spring class is a new offering, Bee Photography. Bees are among the most challenging insects to photograph, and the goal of this class is to help you better document your own bee observations. We'll start with an overview of bee biology and movement in the garden, followed by a discussion of the tips and techniques used by insect photographers. Participants will have the opportunity to use some of the Haven's bee photography tools and to photograph identified bee specimens.

May 16, 12pm to 3pm, register here.  

Also offered last year for the first time, Pruning the Bee Garden will be returning in the fall. Bee gardens are all about flowers, and pruning the Haven's plants is an essential part of creating ample flowers for our bees. In this class we'll learn about the physiology and science behind pruning of ornamental plants and fruit trees, discuss pruning strategies for increasing bloom, review pruning of California native shrubs, and practice pruning in the Haven.

The time for the class has been expanded from last year to allow a more in-depth lecture and ample time for student practice in the garden. Handouts and light refreshments included. 

September 26, 9am to 12pm, register here. 

We've all seen them....garden catalogs or magazine articles with cute little bee houses hanging like birdfeeders, or entire fences made of nesting tubes for solitary bees. We even had them at the Haven -- for a while -- in the form of bee condos. The only problem? They often don't work, and may even do more harm than good.

While the attention devoted to declining bee populations by the gardening world is great, lots of attention to an issue can often lead to misinformation. This led to greenwashing, with manufacturers rushing to claim often dubious 'green' credentials for their products. We now see the same happening with bees; the term 'beewashing' was coined by Scott MacIvor and Laurence Packer of University of York University to describe this phenomenon as it relates to solitary bee houses. In a study of 600 solitary bee nests that they placed in Toronto, they found that native wasps were more abundant than bees, close to half of all bees using the nests were introduced species, and that parasitism of bees using the nests increased as the size of the nest groups increased.

This is not limited to bee houses; previous investigation by Mihail Garbuzov and Francis Ratnieks of the University of Sussex found similar misinformation surrounding bee plant lists. They reviewed lists published for various regions worldwide, and found large variation in recommended plants, even within the same region. The science behind the lists, such as university research or repeated monitoring by trained observers, was also often unclear.

 

So what's a conscientious bee gardener to do?

Bee houses

I've written extensively about solitary bee houses on this blog. In the wild, bees nest in abandoned beetle galleries in trees. This environment is dark, stationary, and made of wood, and can inform our choice of solitary bee housing. Consider the following:

1. Bees will use a nesting tube diameter that corresponds to their body size. A good range of sizes for common bees is 3/16 to 5/16 inch. Tubes should be 4 to 6 inches deep; anything shorter will produce predominantly male bees.

2. Bees will not use houses or nesting blocks that move or are open in the back

3. A shaded entrance is important; even a piece of burlap draped over the top of the nest can work

4. Bee houses constructed of wood seem to be preferred

5. Position house with entrance out of the prevailing wind

6. Pathogens can build up in bee houses as they are used; they cannot be sterilized with bleach or other disinfectants. 'Cleaning' the used nesting tube with a drill bit or brush is likely to push pathogens into the wood. Houses (in the case of wood blocks) or individual tubes should be replaced after they are used. 

7. Consider all dimensions. Bees may nest in hollow stems that are not horizontal.

 

Sedum 'Autumn Joy' showing hollow stems after fall pruning. These may be used by solitary bees the following spring.

Nesting tubes in use. Note that tubes are filled with different material depending on the bee species. Materials include leaf pieces, leaf hairs, and bits of decomposed granite. Tubes on the upper right with chewed holes have been exited by newly emerged bees.

Leafcutter bee nest cross section. Each segment is an individual egg and food provision. The different shape of the front and back of the segment helps the emerging bee to orient itself to the correct direction for exit.

A fact sheet about building and using solitary bee houses is here.

Bee garden plant selection

Use bee plant lists from reputable sources, such as the Haven or the UC Berkeley Urban Bee Lab. These lists are based on years of observation throughout California by bee scientists. The Haven is participating in a 5-year USDA-funded project evaluating plants for bees; in addition to these field plot studies, bee use of plants in the Haven is monitored weekly by student interns and citizen science volunteers. This ensures that our plant recommendations are based many observations across variations in time and weather.