It's that time of year: hurricane-force winds one day and beautiful spring weather the next. Here's what's happening in the Haven in March:
We've finished our winter pruning and are eagerly awaiting the flowers that will follow. Our winter-blooming plants are going strong, providing vital food for the honey bees at the Laidlaw Honey Bee Research Facility next to the Haven. Some top winter-blooming plants for bees include rosemary (Salvia rosmarinus -- yes, rosemary is now a salvia!), germander (Teucrium fruticans),
Our irrigation system is always given a going-over in the winter to ensure there are no leaks and that the precious water is being used as efficiently as our system will permit. We'll be working on this throughout March.
This is the start of the time when the Haven changes almost weekly. If you're planning a visit, things really get going in late March, and the garden remains at its best through the end of May. Thanks to a generous donor, we had the funds to replant one of our display beds this winter. We'll be using additional support from our Crowdfund campaign to refresh our demonstration orchard.
If you'd like to plan your own bee garden, you'll find a searchable plant list on our website. The list includes bloom time, bee resources provided, Sunset growing zones, and water and light requirements. In addition to our full plant list, you'll find several targeted (e.g. low-water, shade, etc.) bee plant lists here.
Yolo County has moved into a lower COVID tier, and we hope to resume guided tours by the last week of March. Pending approval by the University and COVID restrictions on group size, we look forward to welcoming tours back to the Haven. The garden remains open for individual visitors.
In the meantime, we've loaded more videos to our YouTube channel; look for more throughout March.
Thanks to everyone who donated, shared, or otherwise supported our February fundraising effort through Crowdfund UC Davis. We've nearly reached our goal of $2500. Contributions may be made here through February 28. Thank you!/div>/div>/div>
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.
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.
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.
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?
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.
A fact sheet about building and using solitary bee houses is here.
Bee garden plant selection
The Haven is all about teaching, research, and outreach to save the bees. Our programs are consistently rated highly by our visitors; we've grown every year of our existence and would love for that to continue. For details about our past accomplishments, please see our annual reports: 2018, 2017, 2016, 2015, and 2014.
A grant that provided half of our support recently ended, and I am seeking your support to help keep these successful programs going.
What you can do:
1. Donate here. The Haven is supported solely by grants, donations, and volunteers. A generous Häagen-Dazs gift established the garden, but Häagen-Dazs does not provide ongoing support. Recent funding has come from the California Department of Food and Agriculture, the UC Davis College of Agriculture and Environmental Sciences, the USDA, and the California Center for Urban Horticulture.
Individuals and local clubs such as the Roseville Better Gardens Club and the Sacramento Area Beekeepers Association have also made much-appreciated donations.
If the 3500 people who've attended a tour, Haven event, or class so far this year each gave $10, we'd be covered for seven months. While large donations are great, many small donations are just as important.
2. Attend our fall fundraiser on September 21. Details will be posted soon on the Haven's web page.
Thank you. Together we can keep this unique garden going strong.
I've had several questions recently about the Bambeco solitary bee house sold at Costco (they sell the Swiss Alps model), so I decided to head to my local store to check it out. While the price is amazing, the house has a few features that are not so ideal. For details on what makes a good solitary bee house, see here and here.
The depth. At 4.5 inches deep, it is sufficiently deep to allow the production of female and male bees.
What's not so good:
The nesting tube diameter. While the variety of diameters is good, solitary bees need tubes from 3/16 to 5/16 in diameter. While other arthropods, such as spiders, may use the larger tubes, they will not be used by bees.
Limited protected overhang. The nesting tubes should be placed so that the entrance has a bit of protection. That's why we make our houses at least an inch longer than the tubes.
The nesting tubes are glued in place. Once a tube is used it should be replaced to help prevent the build up of pathogens.
March 13, 2019: winter update
The bee house is not holding up well to the winter weather. Here's a photo showing some superficial mold as well as separation of the sides from the base. Note that I added extra protection by attached redwood fence boards to increase the cover of the roof.
March 27, 2019: comments on the 2019 model
Update July 1, 2019
Update October 7, 2019
I have discarded the 2019 bee house. The paint continued to peel and the wood on the roof started to split. I removed the wooden blocks in the front of the house and will use these next year. For folks who have been asking what a correctly designed bee house looks like, here is an example of the one we sell at the Haven.
What makes it correct:
1. It's made out of redwood; studies have shown that bees prefer to nest in wood.
2. The depth and diameter of the nesting tubes are correct. The holes are drilled 5 inches deep, and the openings range from 3/16 to 5/16 inch in diameter.
3. Paper straws have been inserted into the 1/4 inch diameter holes (this is the only size straw available). This means that the tube can be cleaned out after use. I suggest plugging the others with wood filler after use so that they are not re-used.
4. The front of the block has a pattern to it. This may help the bees recognize their individual nest entrance. There is also evidence that a blue front is more attractive to one of the mason bee species.
5. The block has a piece of burlap shading the entrance. Bees are more likely to use the blocks if the entrance is shaded.