- (Focus Area) Natural Resources
- Author: Christine Casey
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?
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.
A fact sheet about building and using solitary bee houses is here.
Bee garden plant selection
- Author: Christine Casey
My last post covered the use of color in garden design from the perspective of what bees see. While aesthetics are important in any garden, the needs of bees come first at the Haven and other bee gardens. Here are a few examples of color combinations that are attractive to us and provide both pollen and nectar for bees.
Shades of purple throughout the year
As was mentioned in my last post, purple is a color that bees see well. Here are some ideas for shades of purple throughout the year:
Winter: rosemary (nectar), germander (nectar), ceanothus (pollen and nectar), phacelia (pollen and nectar)
Spring:ceanothus (pollen and nectar)
Summer: sages (nectar), Russian sage (nectar), zinnia (pollen and nectar), cosmos (pollen and nectar)
Fall: aster (pollen and nectar), bluebeard (pollen and nectar)
Shades of yellow throughout the year
As a complementary color to purple, yellow is attractive against any of the plants listed above. Some yellow flower choices include:
Winter:bidens (pollen and nectar), blanketflower (pollen and nectar)
Spring:bidens (pollen and nectar), blanketflower (pollen and nectar), lupine (pollen and nectar)
Summer: sage (nectar), sunflower (pollen and nectar)
Fall: sunflower (pollen and nectar)
Summer whites
Spring: Santa Barbara daisy(pollen and nectar), buckbrush (pollen and nectar)
Summer: Santa Barbara daisy (pollen and nectar), gaura (pollen), veronica (pollen), coneflower (pollen and nectar), zinnia (pollen and nectar), cosmos (pollen and nectar), California buckwheat (pollen and nectar)
Fall:gaura (pollen), California buckwheat (pollen and nectar)
Hot colors throughout the year
Winter: California poppy (pollen), Cape balsam (pollen and nectar)
Spring: Cape balsam (pollen and nectar), sage (nectar)
Summer: Cape balsam (pollen and nectar), coneflower (pollen and nectar)
Fall: Cape balsam (pollen and nectar), sage (nectar), sedum (pollen and nectar)
- Author: Christine Casey
Spring is here, and planting is underway in bee gardens throughout California. And planting, especially if you're creating a new garden, means you are thinking about design. In this series of posts I will cover various aspects of garden design -- such as color, texture, shape, and size -- from the perspective of what bees need. Based on research, this information should provide a solid foundation for a successful bee garden.
This post will focus on color. An understanding of color theory is helpful in creating an aesthetically pleasing garden for us, but color is also relevant for bees. All color wheel screen shots shown here are from the Adobe web page.
1. Complementary colors. Colors opposite each other on the color wheel are complementary; this is one of the easiest ways to select colors. Using opposite colors together makes each color appear more vibrant.
2. Analogous colors. Colors adjacent to each other on the color wheel are analogous; using these colors can be a bit trickier, especially with hot colors like oranges and reds. One way to combine these effectively is to mix in white, as is done here with white gaura in this planting of the analogous colors pink (echinacea) and purple (tall verbena).
3. Shades of one color. This is the easiest combination to pull off. Cool colors (blues and purples) tend to create a calming effect and make the garden appear larger, while warm colors (reds and yellows) create energy and make the garden appear smaller. Here is an example of shades of a cool color (purple) used in the Haven:
So how do we meld this with bee biology? Here are some pointers:
1. Bees see color differently than we do. They don't see red at all, and see purple very well....there's a reason we have so many purple flowers in the Haven. Here's an example: the first photo shows a flannel bush flower in daylight, while the second shows it under ultraviolet (UV) light, which is the light spectrum where bees see. The 'invisible' nectar (to us) is a bright blue beacon to bees under UV light.
But, you might be thinking, I see bees on red flowers all the time! Well bees can use more than color to find a flower, which brings us to scent....I'll discuss this in a future post.
2. Does color pattern in the garden matter to bees? One study (Proc. R. Soc. London B. 2003. 270: 569-575) found that honey bee foraging distance was longer in simple landscapes; this makes sense because honey bees do best with a varied diet and need to travel further to find a mix of flowers in a simple landscape. Conversely, waggle dance activity was greater in complex landscapes because the patches of plants were more variable -- high quality and low quality plants were mixed together. So it's also important to ensure a good mix of high-quality bee plants in appropriately-sized patches.
3. Another aspect of flower color often not considered is patterns on the flowers themselves. Called nectar guides, these serve to guide bees into the nectary. Of course they pick up and deposit pollen as they do this, thereby pollinating the flower.
For lots more detail about how bees see, check out this article. My next post will cover shape, size, scent, and texture. I'll finish with suggested plant lists and planting plans. Here's to your successful bee garden!
