- Author: Kathy Keatley Garvey
There's a way for a bear to outsmart a fox.
A teddy bear bee, that is.
We just witnessed a male Valley carpenter bee, Xylocopa sonorina, aka "the teddy bear bee," buzz up to a patch of foxgloves, Digitalis purpurea.
Then he engaged in the foraging behavior known as nectar-robbing. That's when a carpenter bee or bumble bee drills a hole at the base of the corolla--or finds a hole already drilled--and "robs" the nectar, bypassing the flower's reproductive parts that lead to pollination.
Hey, I'm not going through the front door! I'm not! I'm taking the back door.
We usually see female Valley carpenter bees drilling the holes and robbing the nectar. This time, though, it was a male. The late Robbin Thorp, UC Davis distinguished emeritus professor of entomology, always referred to the males as "teddy bear bees," adding "boy bees don't sting."
This particular teddy bear lingered a bit, sipped some nectar, and then took flight.
That's how a "bear" outsmarts a fox.
By the way, sexual dimorphism is pronounced in X. sonorina. The male is a green-eyed blond, while the females are solid black.
In our garden, other plants popular for nectar robbing include the salvias, ‘Hot Lips' Sage (Salvia ‘Hot Lips'), and California fuchsia (Epilobium canum). Sometimes you'll see a honey bee following a carpenter bee or bumble bee around to gain easy access to the nectar. She "knows the drill."
Scientists have known about nectar-robbing for more than two centuries. German naturalist Christian Konrad Sprengel observed bumble bees perforating the corollas of flowers as early as 1793, according to Wikipedia. Sprengel recorded this phenomenon in his book, The Secret of Nature in the Form and Fertilization of Flowers Discovered. Charles Darwin observed nectar robbing (by bumble bees) in 1859 and published his observations in his book The Origin of Species.
- Author: Christine Casey
Our understanding of Russian sage's native habitat remains unchanged. It's still not from Russia, but is native to grassland areas in western China, Pakistan, and Afghanistan. These hot, dry, sunny areas have summer weather similar to California's Central Valley so it does well in our gardens.
Here are links to some of the scientific papers describing these changes for those who wish to learn more:
Salvia yangii. National Center for Biotechnology Information. Link here.
Taxon. 2017. Salvia united: The greatest good for the greatest number. Read here.
American Journal of Botany. 2012. Phylogenetics, biogeography, and staminal evolution in the tribe Mentheae (Lamiaceae). Read here.
Please consider supporting our Crowdfund UC Davis campaign. We rely on donations and grants to keep the Haven and this blog going to share accurate, science-based information about bees and gardens. Thank you!
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- Author: Kathy Keatley Garvey
Have you ever pulled up a chair in your garden and watched honey bees foraging?
They are so intent on their "bees-ness" that they don't know you're there. It's a great opportunity to photograph them.
Sometimes, if you're lucky, they'll buzz over your head on their way back to their colony, and you'll see:
- The three main body parts: head, thorax and abdomen
- The two pairs of wings
- The three pairs of legs
- The pair of antennae
Such was the case in Vacaville this week when we were watching honey bees forage in our African blue basil, a bee magnet that we plant annually. We first learned of African blue basil, (Ocimum kilimandscharicum × basilicum 'Dark Opal'), through Gordon Frankie, UC Berkeley professor and the late Robbin Thorp, distinguished emeritus professor of entomology at UC Davis. They co-authored the book, California Bees and Blooms: a Guide for Gardeners and Naturalists (Heyday Books) with Rollin Coville and Barbara Ertter, also affiliated with UC Berkeley.
Want to know more about honey bees? Be sure to read the newly published The Art of the Honey Bee; Shaping the Environment from Landscapes to Societies (Oxford University Press) by noted bee geneticist and biologist Robert E. Page Jr., who maintains strong ties to UC Davis and Arizona State University (ASU). Also learn about honey bee anatomy on ASU's web page, "Ask a Biologist."
Page, who holds a doctorate in entomology from UC Davis, is a former chair of the UC Davis Department of Entomology. In 2004, Arizona State University (ASU) recruited him for what would become a series of top-level administrative roles. He advanced from director of the School of Life Sciences to dean of Life Sciences; vice provost and dean of the College of Liberal Arts and Sciences; and university provost. Today he holds the titles of provost emeritus of ASU and Regents professor emeritus, as well as UC Davis department chair emeritus, professor emeritus, and UC Davis distinguished emeritus professor.
Tool Kit
Did you know a bee has a tool kit? Page lists the tool kit in his book, The Art of the Bee: a compass, an odometer and a path integrator.
'As 'central place foragers,' bees fly out from the nest site and explore the surrounding environment in search of food resources," writes Page, renowned for his research on honey bee behavior and population genetics, particularly the evolution of complex social behavior. "They return to the nest with the resources they collect. To do this, they need to be able to navigate out and find their way back. To aid them, they have a toolkit of navigation mechanisms."
One tool in their tool kit is their internal compass that depends on the location of the sun.
"As light from the sun passes through the atmosphere, it becomes polarized," Page writes. "The pattern of polarized light in the sky depends on the angle of the sun relative to where you are looking. Bees have special sensors in their eyes for detecting the polarized light patterns. On cloudy days, they can't see the sky; but they can still locate the sun using ultraviolet light detectors. Ultraviolet light penetrates cloud cover, allowing bees to use the location of the sun as a navigational marker. With heavy clouds, bees can get to and from a resource by relying solely on landmarks that they learn; otherwise, they stay home until the weather changes. However, as the earth turns, the sun is always changing location relative to the horizon, making it an unreliable marker unless you know the time of day, and bees do. They learn the movement of the sun across the sky and reference it to an internal clock. We know they have the clock because we can train them to forage at specific times of day. If you anesthetize a bee, you can stop her clock. When she awakens and takes a foraging trip to a learned foraging station, her flight path will be offset by the amount of time lost. In other words, she will misinterpret the direction based on the current location of the sun by the amount of time she was anesthetized."
"The odometer plus the ability to determine a flight vector (direction and distance) from a given landmark along a resource flight path, using their sun compass and internal clock, give bees the basic tools for navigation," Page writes. "The last tool in the toolkit is a path integrator that combines the compass and odometer information."
It's a fascinating book by Page, whose most salient contributions to science include constructing the first genomic map of the honey bee, which sparked a variety of pioneering contributions not only to insect biology but to genetics at large.
Meanwhile, take the challenge. Pull up a chair in your garden and watch and photograph the bees going about their "bees-ness."
- Author: T. Eric Nightingale
Planning a drought-tolerant garden can be a challenging endeavor. Knowing which plants to use and where to plant them is difficult as information and advice can vary significantly. However, there are a few simple things you can do to make the process easier.
The first task is to become intimately acquainted with your garden. Watch the way the sun moves and where the shade falls throughout the day. It may seem obvious that how much sun a plant receives will affect how much water it uses, but not all plants labeled for low water use will thrive in full sun.
Knowing the locations in your garden that receive shade from summer heat can greatly affect the health of your plants and the maintenance required to keep them looking attractive.
Note how wind moves through your garden. Evapotranspiration, the loss of water through plant leaves, increases significantly with high, hot or dry winds. On a cloudy yet windy day the plants in your garden could dehydrate more than you expect.
Finally, get up close and personal with your soil. Check its water retention by digging a hole about a foot deep and wide and filling it with water. Hope for the water to percolate through in about an hour, signifying good drainage.
Many drought-tolerant plants, especially succulents and cacti, will rot if soil drains too slowly. Conversely, if the soil drains too readily, it can be difficult to keep even low-water plants adequately hydrated.
All of these factors will help you form a picture of how water will be utilized in, and move through, your garden. This knowledge is a useful tool when choosing new plants.
When working on creating a drought-tolerant garden there are some preconceptions it is best to discard. When many people think of a garden, the image that comes to mind is of a classic English garden. This is understandable as modern home gardening and many of its traditions originated in Europe.
But England has a different climate than Napa, and it is not realistic to expect our gardens to look like English landscapes.The plants found in English gardens are often not good candidates for a Napa Valley garden, least of all a drought-tolerant one.
Many of the best-known annual plants are thirsty in our climate, as are many popular perennials such as hydrangeas, camellias and gardenias. Tropical plants, while visually stunning, are often troublesome as well. Even if they are not labeled as requiring a lot of water, the relatively low humidity in Napa Valley can make it difficult to keep them healthy.
Changing our expectations for our gardens does not mean lowering them. A garden can use less water and remain visually pleasing, lush and colorful. In a sunny location, shrubs such as salvia and lavender can be placed among large succulents such as aloe and agave. The contrast of soft and sharp textures is pleasing to the eye. The salvia will bloom most of the summer, while many aloe, such as Aloe capitate, bloom in the winter.
Many popular groundcover-type plants have shallow roots and need frequent watering. These can be easily replaced by a clumping or vining succulent. A favorite of mine is ice plant, Delosperma cooperi, which produces a carpet of purple-pink blooms from spring through summer.
Identifying plants that work in a drought-tolerant garden is easy after some practice. Generally speaking, plants with large, glossy leaves are a poor choice. These plants will lose a lot of water to evapotranspiration and are prone to sunburn. Plants with dusty or fuzzy-looking leaves are much more adapted to hot, dry conditions.
The roots of a plant can also tell you something about its water needs. Small, shallow roots will need more frequent watering than large, deep-burrowing ones. Never hesitate to gently remove a nursery plant from its pot and inspect the roots. They are a key indicator of plant health.
An important bit of information often missing on plant labels is the term “once established in the ground.” Succulents excepted, a potted plant will usually need more water and fertilizer than the same plant in the ground. Many drought-tolerant shrubs survive by growing broad or deep root systems. It takes at least a year for new plants to develop a useful root system, during which time they will need additional water.
Knowing these facts about your garden and the plants in them, as well as altering your perception of how a garden should look, can make an enormous difference in your relationship with it. You can minimize required maintenance and reduce your stress, leaving only the pleasure of enjoying the beautiful space you have created.
Next workshop: “Home Vineyard: Part 2” on Saturday, September 14, from 9:30 to 2:00 p.m., in Calistoga. Learn techniques to maintain your new or existing home vineyard. Workshop location will be provided after registration. For more details & online Registration go to http://napamg.ucanr.edu or call 707-253-4221.
The UC Master Gardeners are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
By Penny Pawl, U. C. Master Gardener of Napa County
For the last three years I have been battling gophers in my garden. They have pulled artichoke plants down their hole and last summer took out my peppers and eggplants. A young fig tree had only a chewed-on place where its roots had been. In desperation I bought wire cages to plant in.
In my backyard the gophers have taken out every Liriope (mondo grass) and made massive tunnel systems. I stepped in one and my foot went in up to my ankle. I could see inside the tunnel. I left it open but it was closed the next morning so I know there is still a gopher moving actively under my garden.
I know many people are successful using traps to catch and kill gophers but I don't have the intestinal fortitude for that. So over the years I have resorted to other methods. On occasion I have put things down their runways to chase them away, including lighted road flares, dog manure and a hose of running water. I also chased one gopher out of his hole and used a pitchfork to end his life. But none of these actions got rid of the devils.
And what happens to all that soil they moved? I occasionally see a pile, a tell-tale sign of gopher activity, but I don't see big piles.
Their tunnels can affect plants by allowing water to flow underground and by drying out roots that reach that level.
Since gophers have decimated whole areas in my garden, I have started to research just what plants they won't eat. I also had my vegetable beds lined with hardware cloth to keep them out. That approach seems to be working but they do burrow around the beds seeking a way in.
I found a website that has gathered opinions on what plants are gopher proof (https://www.mostlynatives.com/plant-characteristics/gopher-resistant). It lists native plants that seem to be uninviting to gophers. I have also found a few non-natives that don't seem to attract them. If a plant is not to their liking, they move on.
Unlike moles, which are carnivores, gophers are vegetarians and live on many kinds of plants. Once they leave the nest, they are solitary animals and only meet to mate. Their time in their tunnels is spent building up their larder for winter. Their tunnels may be 200 feet long. My husband once dug a gopher out that had gone into a bed we were preparing. He was about three feet deep in his den. They dig deep and wide.
Most plants that don't taste good to a gopher also tend to be drought tolerant so you can kill two birds with one stone. The plants in my garden that gophers have not touched are nandina, fortnight lily, lily of the Nile, daylilies, salvias, hellebores, society garlic, monkey flower and verbascum, to name a few. I plan to use more of these in my landscape.
Recently, my gophers have been busy in a new area. They have almost completely taken out my mondo grass. When they finish, I will plant something they don't like.
I have started to use underground buzzers to drive gophers away from plants they eat. They were pulling the roots off my milkweed, so I set buzzers up on either side. The noise-making devices seemed to stop them, so I have invested in a few more to put around the yard.
Next workshop: “Cool-Season Vegetables: Now is the Time to Plan and Start” on Saturday, August 10, from 9:30 to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Repeated on Sunday, August 11, from 1 p.m. to 3 p.m. in Yountville. For more details & online registration for the Napa workshop: http://napamg.ucanr.edu. Or call 707-253-4221. For the Yountville workshop, go to Online Yountville registration or telephone the Parks & Recreation Department at 707-944-8712.
The UC Master Gardeners are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.