- Author: Christine Casey
Bee gardeners are good stewards of the environment, which includes making the most of our precious water supplies in the garden. But are you getting the most Bees Per Gallon? We've recently completed a five-year study to evaluate the bee-attractiveness of common northern California landscape plants. Funded by the USDA-NIFA-SCRI, this work was part of a US-wide project to investigate how the horticulture industry can support bees. At UC Davis, we evaluated low- and medium-water plants that do well in northern California.
While all the plants we tested were bee-attractive to varying degrees, here are the ten most-attractive plants with WUCOLS ratings of L or VL in the Central Valley region. These are the plants that will help your garden support the most bees with the least water -- the most Bees Per Gallon!
This list is not intended to be a comprehensive recommendation. There are other great low-water bee plants (here's a list on the Haven's website); the most detailed recommendation for California bee plants of all water needs is in California Bees and Blooms by Heyday Press.
Yarrow (Achillea millefolium 'Moonshine' and 'Island Pink')
Full sun
WUCOLS rating for the Central Valley = L
Blooms summer and fall
Grows approximately 2ft h x 2ft w
Sunset zones 1-24
Cape balsam (Bulbine frutescens)
Full sun
WUCOLS rating for the Central Valley = L
Blooms nearly year-round
Grows approximately 2ft h x 3ft w
Sunset zones 8, 9, 12-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms late winter
Grows approximately 1ft h x 4ft w
Sunset zones 5-9,14-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms nearly year-round
Grows approximately 3ft h x 3ft w
Sunset zones 8, 9, 12-24
Full sun
WUCOLS rating for the Central Valley = VL
Blooms summer and fall
Grows approximately 3ft h x 3ft w
Sunset zones 7, 9, 12-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms summer
Grows approximately 2ft h x 2ft w
Sunset zones 2B-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms late summer
Grows approximately 4ft h x 4ft w to 8ft h x 8ft w depending on variety
Sunset zones 7-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms summer and fall
Grows approximately 2ft h x 2ft w
Sunset zones 1-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms summer and fall
Grows approximately 2ft h x 2ft w to 6ft h x 6ft w depending on variety
Sunset zones 2-24
Full sun
WUCOLS rating for the Central Valley = L
Blooms summer
Grows approximately 1ft h x 2ft w
Sunset zones 2-24
- Author: Christine Casey
Lawn removal is on the mind of many Californians these days. In my own neighborhood I've seen many interesting and creative new gardens; one person even made a monument to the lawn of the past that includes an old push mower ringed with stones in a place of central prominence.
If you're taking out some or all of your turf, you have a great opportunity to re-plant so your garden is bee-friendly. Unfortunately, rocks and cacti often seem to be the default options for low-water gardens. While bees use cactus flowers, this type of garden provides nothing else for these important animals.
As an encouragement to do more, here's a concrete patio area at my own bee garden, before and after:
Need some help getting started? Here's a plan for a simple, nine-plant, low-water bee garden for a small, sunny yard. Want more ideas? Check out our list of 25 low-water bee plants that includes bloom times and pollen and nectar resources. You can see all 25 of the these plants (plus many more!) at the Haven.
- Author: Christine Casey
How is the California drought affecting bees? Many Haven visitors have asked that question. Drought affects bees in several ways; the good news is that we can provide some relief in our bee gardens. Some considerations:
Water
Honey bees need water to cool the hive and to dilute the honey they feed to developing bees. This is why it's essential to include a water source in your bee garden. See this previous Bee Gardener post for more information.
Parasites
The honey bee-parasitic varroa mite, Varroa destructor, has had a devastating effect on honey bee health. The good news is that multi-year droughts can reduce the mite's reproductive rate (Environ. Entomol. (2003) 32(6): 1305-1312).
Floral resources
Drought-stressed plants produce fewer, shorter-lasting flowers. Lack of adequate, high-quality forage has been identified in a USDA study as a major factor in bee health decline.
Less obvious than the absence of flowers is the quality of the food they provide. In a study of squash plants subjected to simulated drought, it was determined that the daily pattern of nectar secretion was unaffected by drought. The volume and concentration of nectar declined with the length of the simulated drought, however, indicating a negative effect of drought on the floral resource that bees depend on (Apidologie (2012) 43:1–16).
Many of our native bees are feeding specialists that will only use one species or genus of plant. What happens if that plant suffers during drought? Many animals native to areas with regular dry periods have evolved diapause as a survival mechanism. A study of in bees in the southwestern US desert found that they were able to reliably use environmental cues to enter diapause when their plant resources were affected by drought (Proc. R. Soc. B (2013) 280: 20122703).
Effective use of limited water in the bee garden
Many communities are under mandatory water restrictions, and groundwater levels are at record lows throughout California. How do we balance this with the needs of these vital insect pollinators?
- Save the rest of this year's water for the plants that have yet to bloom. Fall and winter are critical times for honey bee foraging to ensure ample honey stores for the winter. In the Haven we are reducing irrigation to the plants that are finished blooming for the year so we can focus water use on the sunflowers, asters, sedums, and other plants that will bloom until frost.
- Provide an efficient water source. The Haven's self-watering container made from a soaker hose runs on a timer. This provides water for our bees while re-using the water for irrigating the plant in the container.
- Plant drought-tolerant bee plants for next year. We have suggestions on the garden's web site.
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- Author: Christine Casey
Many insects can obtain the water they need from their food. Bees, however, need to drink water. Honey bees use water to make honey and to cool the hive.
As the weather heats up, I thought I'd review some ways to provide water for bees in the garden. This is especially important in this drought year, as some typical water sources such as leaking faucets may not be available. This is what commercial beekeepers do; their “bee board” is just a fancy name for a board leaning underneath a slowly dripping faucet. This can be recreated in a more water-conserving way by placing a board under the faucet of a rain barrel.
This year I've added a water source to the garden made from old soaker hoses.
Here's how it's done: