Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk. You asked about carpenter bees boring a hole in your roof beams and how to get rid of them without killing them. From your description and the description of the holes, it does indeed seem likely they are carpenter bees, but we would recommend getting a positive identification before taking control measures. These very large bees with a loud buzz are quite obvious, the females being large and shiny black. The males are those beautiful golden fuzzy 'teddy bear' bees. You may also see pollen-laden bees entering the hole to feed their babies!
Only the females build nests, boring a tunnel into soft wood, leading to one or several nest cavities. They do not create hives, but several females may use the same tunnel for the nest. They mate and lay eggs in the spring, the young bees developing over several months - there is only one generation each year. These bees can indeed damage wood structures, but unless there are many holes you probably have time to consider control methods. As you do not want to kill them, and there may be young brood inside the nest at this point, you might want to wait until late summer after the bees have emerged. Then you can plug the holes and paint or stain the wood to discourage any further nesting.
Here are some UC links with more information on this bee, and how to manage them.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7417.html
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=8049
We couldn't find any information on how to remove them without killing them - it also seems that even if the adults are excluded, the young bees can chew their way out of the nest after they hatch. So if you can wait, I think you would be fine waiting until later in the summer to paint and fill the holes, and then hopefully they will cause no further problems. Meanwhile, enjoy these beautiful and useful creatures in your garden.
If you are a DIY person, there are plenty of articles found via Google for fixing the holes as well as techniques to assure that the bees don't come back (they can be homing to their birthplace). And there may be contractors around that specialize in "fixing" the problem.
Good luck with this!
Help Desk of the UC Master Gardener Program ofContraCosta County (SMW)
Note: UC Master Gardeners Program of Contra Costa's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone: (925) 608-6683, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog.
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk.
You sent a photo of a plant for us to identify. It is rosemary (Rosmarinus officinalis). While it's not native to California (it originated in the Mediterranean area), it is very well adapted to California's similar Mediterranean climate. Its flowers range in color from various shades of blue to even pink and white. Its growth habit ranges from stiff and erect, rounded, or low and creeping, depending on variety or cultivar.
This plant is also the rosemary used for seasoning food, however some varieties taste better than others. Bees are attracted to the flowers and make excellent honey when feeding on them.
Good drainage and full sun are essential for a healthy rosemary plant. The links following will take you to more information about growing rosemary: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/rosemary.html and http://sonomamg.ucanr.edu/Plant_of_the_Month/Rosemary/.
Happy gardening!
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: UC Master Gardeners Program of Contra Costa's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone: (925) 608-6683, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog.
Client's Request: Can you give me some help on locating bee-friendly plants that are extremely drought tolerant (we have typical clay soil with a thin cover of mulch)—Thanks
There are a variety of bee-friendly plants that are drought-tolerant.
To get started, the University of California's Urban Bee Lab has a list of best bee plants for California: http://www.helpabee.org/best-bee-plants-for-california.html. Most of the plants listed are drought-tolerant. In general, they note if additional water is required.
Further information is available from the California Native Plant Society (CNPS). It has a good article on establishing a bee-friendly garden: http://grownatives.cnps.org/2013/03/25/to-bee-or-not-to-bee/. The article provides a starter list of plants plus advice on the characteristics of a good bee-friendly garden with emphasis on growing a variety of plants in terms of size, shape, and colors and differing blooming periods. Advantages of native plants is that they are typically drought-tolerant and many are adapted to clay soils.
You can also use the Sunset Western Garden book sfor descriptions of many of the plants on both lists. CNPS also has a database of natives that you can use for reference: http://calscape.cnps.org/.
Keep in mind that drought-tolerant plants are best planted in the fall so that they can take advantage of the fall and winter rains. So, now is a good time to plan your garden. I usually start looking and buying native plants now while the selection is often greater and then care for them in their containers awaiting fall planting. Also, keep in mind that even drought-tolerant plants will require water for the first several years to get established.
Good luck with your bee-friendly drought-tolerant garden. Please feel free to get back to us if you have further questions.
Note: Both pictures above aref from the Bringing Back the Natives 2015 Tour in the Bay Area. there are many pictures of bee garden on their web site that should give you plenty of ideas about planning and planting a bee garden.
Help Desk of the Master Gardeners of Contra Costa County
Note: The Master Gardeners of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/
/span>/span>Assistance for the Home Gardener from the Contra Costa Master Gardeners Help Desk
CCMG Help Desk Response: Thank you for contacting the Contra Costa County Master Gardeners. It's always a good idea to check the toxicity of a pesticide before using it! Neem oil is a naturally occurring pesticide found in seeds from the Neem tree (Azadirachta indica). While Neem Oil has a very low acute toxicity rating for people and other mammals, it can be toxic to bees if not properly applied.
The University of California considers Neem Oil as moderately toxic to bees and recommends application only during late evening, night, or early morning and when plants are not blooming, i.e., when bees are not typically out foraging.
The following UC IPM (Integrative Pest Management) website provides additional information on Neem Oil (http://www.ipm.ucdavis.edu/TOOLS/PNAI/pnaishow.php?id=53). When applying any pesticide it is very important to follow the label directions precisely, take all necessary precautions, wear appropriate safety equipment, and only apply the pesticide where appropriate and necessary for a specific pest. The following UC website provides guidelines on the safe and effective use of pesticides http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74126.html.
If you are interested in reading more about pesticides and bees, UC recommends the article "How to Reduce Bee Poisoning from Pesticides" by Oregon State University on the web at http://www.ipm.ucdavis.edu/PDF/PMG/pnw591.pdf.
Please feel free to contact us if you have any additional questions.
Contra Costa Master Gardeners Help Desk
Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/
- Author: Shannon Wolfe
First, I want to say that I have never had an infestation of carpenter bees. I just enjoy seeing them in my front yard. If my home or any of my fences were suffering from an infestation of carpenter bees, I might have to rescind this post. If you think you might have an infestation of carpenter bees, please check out this link.
I think most, if not all, home gardeners have heard about the plight of the honeybees in the past few years. But did you know that there are most than 25,000 species of bees around the world? The United States is home to about 4,000 species. Both honey bees and bumble bees (family Apidae) are what are called "social" bees - meaning that they create colonies (hives) and work as a team. I was surprised to learn during my training to become a Contra Costa County Master Gardener that most native bees are solitary bees - I did not know that any bees were solitary! Carpenter bees fall into this category - a solitary bee.
Just because carpenter bees are solitary and do not belong to a colony does not mean that they are not good pollinators. The carpenter bees that I see most often are buzzing around my front yard - specifically around the Hot Lips Sage that grows in the front corner of my front yard
Now, you might wonder, why are these bees called carpenter bees?They make their nests in old wood - in fence posts and eaves most commonly in developed areas. Digger bees are similar in appearance and size to carpenter bees, and they make their nests in bare soil.
I do not know why, but I have always enjoyed seeing one or two of these big, black beauties buzzing around my yard. In researching for this post I learned that male carpenter bees, which are the solid black ones I see most often, cannot sting. So yes, I enjoy them even more now! So keep you eyes open, and the next time you see one of these beauties thank them for the solitary hard work they do in pollinating our plants!