The NEW Honey Bee Discovery Center in Orland

Discovery Sign from Side of Building
Discovery Sign from Side of Building

A few weeks ago, I was invited to the Honey Bee Discovery Center Kick-off and Exhibit Preview in Orland, California. This event was followed by the Queen Bee Festival the day after. The Honey Bee Discovery Center is ‘the first interactive exhibit and museum of its kind’. It highlights the history of beekeeping from hobbyists, sideliners and commercial operators’ perspectives, and features the evolution and breakthroughs in equipment, pollination and art inspired by bees.
Inside the center, one can find multiple showcases of vintage bee equipment related to all apicultural activities, complete with an observation hive near the center of the room. All around the new center, visitors can find many bee related pictures and education opportunities.

Front of the Discovery Center
Front of the Discovery Center

Similar to many museums, the Honey Bee Discovery Center will have a permanent collection and special exhibits. The different glass enclosed displays will be changed frequently with different beekeeping related collections, so it is just like an art exhibit, but all about bees! This will make each visit to the discovery center unique as some items on display will be from personal collections and only appear once while other donated items could be displayed several times. The discovery centers collection is quite large.

Overall it was a great experience to see the exhibit first hand and to see the work that went into the preparation of this center. I feel the center will only improve over time as more displays and events occur there, increasing its popularity in the beekeeping community it is closely tied to. I highly encourage a visit to the Honey Bee Discovery Center, there is something for all ages and it is a sight to see!

Discovery Center from the back
Discovery Center from the back

2019 California Spring Update

Many California beekeepers reported that the start of this year was the worst in 20+ years. Several factors contributed to this year’s issues, starting with the numerous fires last year causing nearly 3 months of smoke in the area.

A beekeepers yard in September showing smoke from fires in Northern California 2018.
Petal Fall in 2019 in almonds after heavy rain.

Once the days got longer, queens started laying but the temperatures dropped again and egg laying stopped once more resulting in smaller colonies after almonds. In fact, most colonies were 2-3 weeks or even a month behind, which delayed the start of queen production. Many producers had to source bulk bees from beekeepers further south to begin starters, builders and nucs.

Italian Queen selected for hygienic testing.
Carniolan Queen selected for hygienic testing in 2019.

Once queen producers started generating nucs, the weather conditions were still challenging enough that the windows of opportunities for queens to mate were narrow at best. However, many queen producers found the first round of catching queens resulted in better than expected mating percentages, allowing them to somewhat catch up on orders and start replacing their own queens. Around this time beekeepers were treating with terramycin to combat European foulbrood (EFB). Some beekeepers believe as I do, that fungicides play a roll in colonies being more susceptible to brood diseases especially EFB. I do think that some of the EFB outbreaks we see are due to the way commercial beekeepers and queen producers manipulate colonies to shake bulk bees.

Early EFB symptoms, orange arrows indicate larvae I would select for testing, red arrows indicate old larvae I would not test


If you are seeing this or lots of Deformed Wing Virus (DWV) it will be really hard to nurse colonies back to health. This is what happens if you neglect to treat or manipulate colonies to impact mite levels. Red arrows point to varroa mite in or on open brood.

Currently queen producers are re-queening and treating their colonies before shipping off to summer honey and pollination locations. The late spring has provided more rain than the past 8 years and many beekeepers say that rain in May increases the star thistle crop. We are hopeful this year will be a great star thistle honey crop, helping to restore lost colonies and recover some of the income lost due to the late start on queen production.


Almond Math

There are plenty of quick stats you come across working around bees: At peak population, a strong colony can have over 60,000 individual bees. A queen is capable of laying more eggs in a day (up to 2,000) than there are minutes in a day (1,440). A single bee can produce 1/12 tsp honey in its lifespan and may cumulatively travel 500 miles during the several weeks it spends as a forager. Despite annual losses in the 30-40% range, the total managed colony numbers remains fairly constant at about  3 million.

The American bee industry is inextricably linked to the almond industry. Every year, about 3/4 of the national herd migrates from various wintering locations to the central valley of California for the almond bloom in February. The almond industry also has some eye-opening statistics: The 117,000,000 almond-producing trees in California are responsible for 82% of global almond production, and it is estimated that it takes approximately 1 gallon of water to produce a single almond. The Almond Board of California does a fantastic job summarizing and quantifying the industry in the annual Almond Almanac available here. A couple previous BIP blogs discussing bees and almonds are available here and here.

Given the link between almond and bee industries and the eye-opening numbers in both, it got me wondering how many almonds each bee produces, or how many bees it takes to produce a single kernel (almonds aren’t technically nuts). Do you think a single bee accounts for hundreds of almonds? Does it take dozens of bees to produce each almond? Pick a number and we’ll work through some estimates to see how close you come.

Each almond starts with a bee in a blossom

The population of honey bee colonies is often estimated in a unit called frames of bees (FOBs). A frame of bees is defined as a deep frame (apx 19” x 8.5”) well-covered with adult bees on both sides. Estimates range between 2000 and 3000 individual bees per frame. For the sake of this exercise I’ll use the 2400 bees per FOB estimate reported here.

Beekeepers that rent their colonies for almond pollination typically do so under a contract that specifies both a minimum acceptable size and an average colony size that must be met. A commonly used contract may specify a 4 FOB minimum and an overall average of at least 8 FOB with potential bonus payments for colonies exceeding standards.  During the month of February 2018, Bee Informed Partnership  Tech Transfer Teams inspected over 1,100 colonies from 38 different operations with the overall mean frame count being 8.96 FOB per colony, so we’ll use that number as an estimate for colony strength. It is worth noting that not all bees in a colony are foragers and the percentage of individual bees that forage increases with colony strength. Randy Oliver has an excellent summation of the pollination value of a colony relative to FOB available here. Considering the difficulty of accounting for variable percentage of foragers and also the fact that a colony could not function with foragers alone, we will consider the total number of bees present to all be needed in order to provide pollination.

It is estimated that in recent years approximately 1.9 colonies per bearing acre have been required to meet almond pollination demand. For the 2017/18 almond crop year, there were an estimated 1,000,000 bearing acres. For the same year there was an average yield of 2,270 almonds lbs/acre. For a total crop of 2.27 billion pounds. It is estimated that there are 368 almond kernels per pound.

Having accumulated the numbers above we can now go about calculating the total number of bees pollinating almonds:

2400 bees/FOB * 8.96 FOB/colony = 21,504 bees/colony

1,000,000 acres * 1.9 colonies/acre  = 1,900,000 colonies

1,900,000 colonies * 21,504 bees/colony = 40,857,600,000 bees pollinating almonds

How many almonds do those 40 billion bees produce?

2.27 billion pounds * 368 almonds/pound = 835,360,000,000 almonds

835,360,000,000 almonds/40,857,600,000 bees =20.45 almonds per bee

Each of the approximately 40 billion individual bees rented for pollination is responsible for producing a handful of almonds.


So there we are, each bee that gets set in California almonds accounts for about 20 almonds. My guess before gathering any of the numbers was about 10 per bee; how close did your guess come?


It’s Cold (and Wet) Out There


This dead forager was one of the few bees I saw on an almond blossom during the early bloom period. She likely succumbed to hypothermia after spending the night away from the colony (note the damp matted hairs).

I don’t know what the groundhog did or saw this year, but according to the calendar it’s still winter. The first day of spring is still a month away. If you’re a pollinator or grower of almonds, you’re hoping weather conditions up and down the central valley of California become more favorable for flight activity than they have been. I recently returned from 2 weeks of inspecting and sampling colonies where conditions were cold, wet, and windy. These conditions delayed onset and slowed progression of the almond bloom and are forecast to continue. Frequent updates on the progression of bloom and conditions for flight are available from Blue Diamond.


The abundance of water and scarcity of flowers in this orchard near Chowchilla, CA characterized the first half of February in most of the central valley.
Muddy conditions prevailed as the last of the colonies were being set.

In addition to the revenue from pollination fees, beekeepers also count on floral resources provided by the 1,000,000+ acres of almond trees that stretch roughly from Chico in the north to Bakersfield in the south. Many colonies get stimulated with feed prior to bloom to boost brood production and size.  If there is not a smooth transition from supplemental feed to forage, because of inclement weather, colony growth can be hindered. If cool and wet conditions persist, many beekeepers may need to resume supplemental feeding to avoid starvation. The persistent wet conditions can also be problematic for growers and lead to increased application of fungicides which may be perilous to bee health.


Aside from the biotic implications for the bees, there are also practical difficulties for beekeepers. In the last few days there have been an abundance of photos and videos online of colonies submerged in orchards or swept away by flooding rivers. Some beekeepers have had truckloads of colonies get snowed in on mountain passes into the valley where wintery conditions have closed highways. At the very least, getting in and out of orchards to deliver or work colonies has been a muddy mess. With so much of the national herd sitting in one location, the implications of the current and near future conditions in the region may ripple across the country this season as colonies are dispersed post-pollination.


Bee Understanding

Earlier this year I had the opportunity to take part in the filming of a documentary by the Bee Understanding Project and it turned out to be a very fun and informative experience! The point of the film was to show the relationship between the almond and beekeeping industries through a job swap, where each participant, almond grower and beekeepers, could better see the other’s perspective. Unlike many other recent honey bee documentaries, this film does not portray commercial beekeepers or almond growers as the bad guys, but rather is fair in describing the challenges each of them faces as our agricultural systems become more industrialized. This short film took an optimistic approach and featured the collaborative efforts of beekeepers and almond growers working toward a more sustainable future.

Blake Davis and Russell Heitkam discuss the benefits of planting cover crops between rows of almond trees. In this case daikon radish has been planted, providing additional forage for bees and improving drainage of the orchard soil.


Beekeepers Russell Heitkam and Jason Miller worked together with Almond growers Ben King and Blake Davis. In addition, the project also enlisted Bo Christie, a Pest Control Advisor specializing in almond pests and treatment, and myself as a honey bee health consultant and a Tech Team member for the Bee Informed Partnership. We all hit it off very well from the start and enjoyed sharing our expertise. It was entertaining watching the film crew try to get into bee suits and work around the bees. They were all good sports, and although no one got stung in the end, it was an experience they won’t soon forget!

I learned a lot from this experience. One of my favorite parts of the job swap was going into the orchard and really looking closely at the trees. I spend a lot of time in orchards while looking at bees but it’s easy to take the trees for granted and stop noticing them. While we were filming, Northern CA experienced a very unusual cold snap that had all the growers scrambling to protect their crops. Bo Christie showed us how to cut the tiny almonds in half and look for the dark frost-damaged tissue.

One of the biggest threats to the almond crop is the orange worm, which lives in the “mummies,” or nuts that weren’t shaken off the tree the previous fall. We all broke up in search of a worm to film, which involved running around the orchard looking for mummies, cracking them open, and checking for signs of the larvae burrowed in the nut. I’m happy to say I found the worm that made its star appearance in the film!

Bo Christie explains how the navel orange worm threatens the almond crop and the importance of keeping it under control.

Another favorite moment was seeing the beautiful cover crops of mustard and daikon radish blooming in the orchard lanes. Ben King pulled up a radish with a root system bigger than his forearm, which demonstrated well why this particular crop is such a great plant for improving soil aeration. It’s especially amazing considering how hard, compacted, and impermeable orchard soil tends to be.

After the filming was over I continued to think about the issues everyone brought up, but the one missing piece that wasn’t really discussed in the film is the consumer. The average shopper is starting to think more about how their food is grown as people make the connection between our food systems, human health, and the health of our environment. I think it would be great to have a “bee-safe” certification program for almonds and other produce, similar to the Salmon-safe label being used on wine, beer, and eggs ( To get certified, growers would have to demonstrate they are organic or follow strict pesticide guidelines, and are planting cover crops or additional forage.

Overall, the Bee Understanding Project film covered the topic in a clear, entertaining way. The aerial drone footage of bees being loading and shipped off was my favorite part, we usually don’t get that perspective! The full documentary can be seen here on YouTube:


Wintering Sheds: Why are more North American beekeepers overwintering their bees in cold storage?

More and more US beekeepers are starting to place their bees in sheds for the fall, for indoor wintering. While beekeepers in Canada have done this for decades, the popularity of the practice in the US is more recent. Beekeepers began by using structures already built for onion and potato storage in Idaho to house their bees in the fall. These beekeepers then remove the bees in January, and bring them to California for almond tree pollination. Many beekeepers are still using old potato and onion sheds in Idaho, but as the popularity of this practice has increased, some beekeepers have built sheds just for the purpose of overwintering bees. These sheds are far from the dirt floor, onion and potato sheds of Idaho. They are clean, new structures with air filtration and ventilation systems, vacuums, Carbon Dioxide and Oxygen monitors, temperature monitors, and cooling systems. Why are more beekeepers choosing to use cold storage and winter their bees indoors?

A clean, newly built wintering facility

I surveyed beekeepers on the Midwest Tech-Transfer Team, asking them why they put their bees in sheds. While the most candid beekeepers admitted they want a vacation for themselves after a long, hard year (they can take some time off instead of working to keep their bees fed and healthy in California), all the beekeepers storing bees in sheds believe the practice is good for the health of their bees.

Bees inside an indoor wintering facility


Here are some of the reasons beekeepers gave:

  1. Bees in sheds are dormant, so beekeepers don’t need to buy sugar or spend time feeding and working colonies. This can save beekeepers money, since the California landscape in Nov/Dec cannot support colonies without supplemental feeding. The bees in sheds are not flying, foraging, or rearing brood (activities that require a lot of energy), so they can conserve energy and build up body fat.
  2. Wintering sheds stay cold and dark, so colonies are broodless. Some beekeepers consider this broodless period to be a mite treatment, because Varroa mites are not able to reproduce without brood. This means that mite numbers will not increase, and mites in the colony may die or get too old to successfully reproduce. Therefore, colonies could potentially begin almond pollination with low mite loads.


  3. Since the colony goes through a “winter,” and is dormant, the queen does not lay for a period of time. This gives the queen a break from laying eggs. Some beekeepers said that this break increases queen longevity.
  4. When the colonies are put on the ground in California, they experience a dramatic change in temperature. The queen starts laying again very quickly, which some beekeepers said leads to a population boom. If the colonies spend the winter in California, the temperature is variable, and increases slowly in February and March, causing the bees to ramp up their brood production through a slow process. Some beekeepers said their shed bees look healthier and bigger during almond pollination, and said this is likely due to the quick jump these colonies make to rearing brood again.
  5. Bees build up Carbon Dioxide within their colonies when they are in a confined space where ventilation is restricted. Letting CO2 levels build up too much can kill bees, but since mites are smaller, it takes less CO2 to harm them than it takes to harm a bee. Some scientists are working to find a “sweet spot,” meaning a CO2 level that is not harmful to bees but is to mites. While beekeepers are not relying on sheds as their main mite treatment right now, many beekeepers have hope that with further research, it could be the key to starting the year with healthy bees.




Thank you to all the beekeepers who answered my questions, and for Steppler Honey Farms for allowing me to use their photos!


Lucky-hit Nectar in Creeping Charlie

Creeping charlie has taken over this backyard

In the twin cities, spring brings complaints- about creeping charlie taking over lawns, strangling garden plants, and being generally relentless. But is the creeping charlie flower a good source of food for bees? In researching creeping charlie, we uncovered a fascinating story about this invasive plant’s strategy to draw insect pollinators. Creeping charlie draws a lot of insect visitors, including bees. Sweat bees, bumble bees, and honey bees are among its most popular insect visitors. Creeping charlie flowers have an interesting strategy for rewarding pollinators. This strategy is called “lucky hit.” They produce nectar with an average volume of 0.3 mL per flower, but the amount of nectar varies greatly, with a range of 0.06-2.4 mL of nectar available per flower. Out of 805 flowers, Southwick found that 8% (64/805 flowers) had a large volume of nectar, and the rest of the flowers provided almost none. The availability of nectar also varies throughout the day. As the morning fades into afternoon, “lucky hits” become less frequent, as creeping charlie flowers do not replenish their nectar throughout the day. Most flowers produce their nectar at night or in the early morning, so it is believed that all the “lucky hits” available in the afternoon are ones that were missed by bees and other nectar collectors earlier in the day. This raised an interesting question- is it energetically efficient for a bee to visit creeping charlie? Southwick found that foraging on creeping charlie likely does provide a net gain of energy. Each lucky hit provides enough calories for 5.9 minutes of foraging, and with the density of flowers produced by creeping charlie plants, bees can probably visit enough flowers per minute to make an energetic profit. The plants are able to produce less nectar over time (even though they sometimes they produce a lot), and so conserve energy. As long as they produce ‘lucky hits’ enough to be an energetically profitable food source, bees will continue to visit. Additionally, the lucky hit strategy may increase pollination success for the flower. Assuming bees cannot tell whether a flower is a lucky hit until they are actively visiting, the bees that visit must be persistent to hit the jackpot. Since they don’t spend a lot of time on flowers without nectar, but still transfer pollen from flower to flower during their search, they may pollinate more flowers per minute than they would if each flower had an average amount of nectar.

Photo by Anne Burgess

While Creeping charlie could be a good nectar source for bees, we are not recommending that you let it take over your lawn. Bees need more than nectar- they also need pollen (the main protein source for bees). Pollen is not readily available from creeping charlie. Bees also need a variety of food sources, and the best lawns have many kinds of flowers, hopefully with a range of bloom times. Creeping charlie is invasive, and can prevent you from growing other types of flowers in your lawn. If you are looking to promote pollinator health in your lawn or garden, we recommend planting a diversity of flowers that produce high quality nectar and pollen consistently over the growing season. James Wolfin, a masters student in the Spivak lab studying bee lawns, has provided tips, below, for excluding creeping charlie when establishing a lawn and eradicating it if it has already established. That being said, if your lawn/garden is already overrun with creeping charlie, and you have not had a chance to eradicate it yet, take pleasure in seeing the bees buzzing around it, and look out for when they spend extra time on one bloom. They are likely hitting the jackpot!

When does creeping charlie grow? (Establishing a lawn without creeping charlie)
Creeping charlie prospers most in shaded areas that have poor ground cover, but can become present throughout the entirety of a lawn, especially in situations where there is an abundance of bare ground, or where turf coverage density is low. Once established, creeping charlie has the ability to suppress the growth of surrounding plants, due to a characteristic called “allelopathy”. This means that it releases chemicals into the ground that suppress the growth of surrounding plants. One study (Rice, 1986) found that flowers growing alongside creeping charlie experienced decreased seed germination and faster rates of root and shoot growth.

The first thing to consider when establishing a home lawn should be species selection. Kentucky bluegrass is typically the preferred grass in the Northern US, due to its high quality and winter hardiness, but it struggles in shady areas, leading to poor turfgrass coverage. The combination of bare ground soil and shade serve as an ideal habitat for creeping charlie to establish and potentially spread. To avoid this situation, it is important that homeowners seed grasses that are well adapted to shady areas. Both tall fescue (Festuca anrundinacea) and fine fescue (Festuca spp.) are cool-climate turfgrass species that do grow well in shady areas. You can mix fescues with Kentucky bluegrass to ensure that you have a strong density of grass, even in the shady areas of your yard.

Eradicating creeping charlie
If creeping charlie has already established in your lawn, there are 2 easy ways to eradicate without using chemicals. You can use a sod-cutter, a machine that typically removes sod for transplant into a new lawn, but can be used to quickly remove strips of weeds, like creeping charlie, from a lawn. Removing strips of creeping charlie will create an area of bare soil within the lawn. This is the ideal habitat for creeping charlie to establish, so it is important to completely eradicate it promptly seed with high quality grass to ensure dense, uniform germination throughout the area.

You can also eradicate creeping charlie through solarization. To solarize, you place a clear, plastic sheet over the soil when it is hot and sunny. The clear plastic sheet captures heat and sunlight, raising soil temperatures to the point where grasses and weeds can no longer survive. Solarization is best fit for sunny, flat sites that are below ½ of an acre in size. In cooler climates the process of solarization takes the better part of a growing season, typically 5-6 months, or up to a full year in some instances. The plastic should be removed in the late fall when soil temperatures are 35-55°F so that new grass can be installed via dormant seeding. These temperatures are ideal because the soil is too cold for germination to occur, but the ground is not yet frozen. This ensures that the target species will be the first to germinate. In the spring, the new turfgrass area should be dense, uniform, and free of weed pressure.



Works cited: 

Dickinson, R. and Royer, F. Weeds of North America, University of Chicago Press, Chicago, IL. 2014

Foord, K. 2016. The value of lawn weeds for pollinators: Not all weeds are created equal. Yard and Garden News, University of Minnesota Extension. Accessed 06/19/17

Hultén, E. 1971. The Circumpolar Plants. II. Dicotyledons. Almquist & Wiksell, Sweden.

Hutchings, M.J., Price, E.A.C. 1999. Glechoma hederacea L. (Nepeta glechoma Benth., N. hederacea (L.) Trev.)
Rice, E.L. 1986. Allelopathic growth stimulation. The Science of Allelopathy (eds A.R. Putnam & C.S. Tang), pp. 34-40. Wiley, Chichester, UK.

Southwick, E. E. “Lucky Hit” nectar rewards and energetics of plant and pollinators.” Comparative Physiology and Ecology 7.2 (1982): 51-55.

Southwick, Edward E., Gerald M. Loper, and Steven E. Sadwick. “Nectar production, composition, energetics and pollinator attractiveness in spring flowers of western New York.” American Journal of Botany (1981): 994-1002.


Tart Cherry Pollination

The summer of 2017 is an exciting time for the Bee Informed Partnership as industry support and beekeeper interest has facilitated the expansion of a new BIP Tech Transfer Team based in Michigan. This expansion into a new territory means learning about the specifics of the local landscape, agricultural systems and beekeeping calendar in order to better serve the local beekeeping operations. Most Michigan-based beekeeping operations spend the winter in Florida or other warmer states and return to Michigan in the spring for fruit pollination and honey production through the summer and autumn.

Cherries are an important part of the local economy and point of local pride in the Traverse City area.

Tart cherries are one of the most prevalent pollination crops   in Michigan and many beekeepers rent their colonies to orchardists during the spring prior to moving them into summer honey production yards. The Montmorency cultivar makes up nearly all of the commercially produced tart cherry crop nationwide with Michigan accounting for approximately 75% of the tart cherries produced nationally. The industry is centered around the Traverse City area, which is known as the “Cherry Capital of the World” and hosts the National Cherry Festival annually around the 4th of July.

There are 32,000 acres (NASS, 2011) of tart cherry plantings in the state, with the industry concentrated in the “fruit belt” on the western side of the state bordering Lake Michigan. This fruit belt is characterized by sandy loam soils and benefits from the climactic effects of proximity to the big lake with tart cherries generally being hardy in climate zones 4-7. The moderating impact of the lake somewhat delays the bloom timing, therefore lowering the chance of a damaging frost post fruit set. This region of the state also has large acreages of other specialty crops including sweet cherries, apples, peaches, pears, grapes, hops, and a variety of berry crops.

Montmorency cherry orchard blooming in Oceana County

Unlike many varieties of sweet cherries (Prunus avium), tart cherries (Prunus cerasus) are self-fertile, meaning pollen transfer is only required within individual flowers on the same tree and orchard plantings do not need to include pollinizing varieties. Tart cherries bloom in the May when weather in the region can be cool, wet, and windy often hampering pollination efforts.  Despite their self-fertile capabilities tart cherries do benefit from honey bee pollination with reports indicating that yields are substantially increased  by the presence of honey bee colonies during bloom. Cherry blossoms provide ­both pollen and nectar to foraging bees. Cherries are a relatively good source of spring pollen which is dark yellow in color but nectar is generally not gathered in quantities large enough to produce substantial yields of surplus.

To maximize pollination in what can be brief windows of suitable conditions growers are recommended to stock honey bee colonies in the orchard at a coverage of 1-1.5 per acre The bloom period for cherries where they are receptive to pollination is generally 7-8 days although this can be accelerated or slowed by hot or cold weather patterns. Bees are typically in for two weeks or less and the rental fees are in the range of $50-55 per colony. Honey bees typically visit cherry blossoms in the morning so it is recommended that growers avoid activities that may disrupt bee activity (such as mowing and spraying) during this time.

Forager on cherry blossoms



In addition to honey bees some growers have begun supplementing hired honey bee colonies with mason bees (Osmia spp). Honey bees do not typically forage at temperatures below 55F so creating suitable habitat for other pollinators that are capable of foraging at lower temperatures can help achieve fruit set during periods of marginal weather. “Over pollination” leading to a need for extensive thinning of fruit is rarely a problem with cherries as it can be in other crops. The crop typically matures 2-3 months after pollination with harvest occurring in mid-July. Harvest is done mechanically by shaking the trunk and collecting the fruit in tarps where it is then immediately submerging it in cold water to preserve freshness limit bruising and separate debris. The vast majority of the crop is processed by freezing, drying, canning, or juicing.


Ripe Cherries are a sign of summer in western Michigan



Clover Seed Pollination

Colonies pollinating crimson clover near Silverton, OR

Clover seed is an important crop grown in western Oregon that benefits rom hired honeybee colonies to boost yields. The Willamette Valley has an ideal climate for seed production with high annual rainfalls that allow growing without irrigation but infrequent rains in July and August allow seed to be harvested with limited risk of moisture damage. There are three main types of clover grown for seed in Oregon with all belonging to the Trifolium genus of the Fabaceae family. They are red clover (T. pratense), crimson clover (T. incarnatum) and white or Dutch clover (T. repens). In addition to clovers the Fabaceae family includes other legumes like peas, beans, lentils, soybeans, and alfalfa.

A pollen forager gathering the chocolate colored pollen from crimson clover

Legumes are nitrogen fixers that produce nutritious forage for livestock as well as being used as green manures. The ability to fix atmospheric Nitrogen (N2) into plant accessible form of Ammonium (NH4) through symbiotic Rhizobia bacteria contained in root nodules allows clovers and other legumes to become rich in plant proteins. Clovers and other legumes are a common inclusion in a crop rotation system through ‘green manuring’ where crops are tilled back into the soil allowing captured Nitrogen to be converted to plant accessible nitrates (NO3) by soil microbes during decomposition. This cycle improves soil fertility for subsequent plantings and helps farmers to maintain higher productivity without increased fertilizer input costs.

Bumble bees also pollinate clover including this Yellow-faced bumblebee (Bombus vosnesenskii) on red clover
Bumble bees also pollinate clover including this Yellow-faced bumblebee (Bombus vosnesenskii) on red clover

It is recommended that a stocking rate of at least two colonies per acre be used to ensure adequate pollination of clover seed crops. White clover and crimson clover, with their relatively short florets are readily worked by honeybees with nectar being relatively easy to attain. Red clover has a longer floral tube, so nectar is not as accessible to honeybees. Bumble bees (Bombus spp.) and other pollinators with longer tongues are better able to access nectar from red clover and are therefore more efficient pollinators but are generally not abundant enough to effectively pollinate large plantings of red clover. Managed honeybees, although not as efficient as bumble bees can do an adequate job of pollinating red clover if there is not too much competing bloom nearby to lure them from red clover plantings. As with all insect pollination, the weather during flowering is hugely influential on the availability of nectar and activity level of insects. Red clover is usually planted in the spring, flowers begins to flower in May and is harvested in late August or September.

White clover field near Shedd, OR
White clover field near Shedd, OR

White clover is grown as a perennial in the valley where and it is usually grazed in the autumn after harvesting in August and again in the spring to stress the plants and encourage seed production. Pastures are typically left in white clover for 2-4 years to improve the soil quality and then put into grass seed production. Crimson clover is grown for seed on the foothills around the Willamette valley where it is an autumn sown annual that is harvest in late June. Clover honey is white to pale in color and can be readily creamed through controlling the granulation process. It is one of the most common monofloral honeys available and many consumers enjoy it for its mild floral flavor.


Meadowfoam Pollination

A forager resting on a recently opened Meadowfoam flower

May in the Willamette Valley is a time of lush green fields of grazing pasture and grass seed crops covering the flatlands along the I-5 corridor from Eugene to Portland. These verdant fields are punctuated by small plantings of dense, low growing, brilliantly white flowers, appropriately called Meadowfoam. Meadowfoam (Limnanthes alba) is an annual oilseed crop with a native range from Vancouver Island, BC to northern California. The oil derived from Meadowfoam seeds contains long-chain fatty acids that are very stable relative to other vegetable oils. This resistance to degradation make it a valuable ingredient to prolong shelf life of products and it is of particular value to the cosmetic industry.

Colonies pollination a Meadowfoam field near Corvallis, OR

Meadowfoam pollen is heavy and sticky making it more suitable for insect pollination than wind pollination. Honeybee foragers are able to gather both pollen and nectar from Meadowfoam fields. The recommended stocking rate to maximize production is at least 3 strong colonies per acre. Saturation of pollinators is important to maximize pollination since individual flowers are only receptive to optimum pollination for a 24 hour window. During peak bloom 4-6 million new flowers per acre open on days with favorable weather. Meadowfoam is moderately attractive and there are many other coinciding blooms so it is recommended that colonies be brought in when 5-10% of Meadowfoam flowers are open to discourage bees from seeking competing blooms beyond the boundaries of the target field.

A forager collecting the cream colored pollen

Meadowfoam flowers are self-fertile but they exhibit protrandy with pollen maturing before ovules are receptive to pollination. This offset in timing within individual flowers results in pollen from anthers of one flower being transferred to receptive stigma of another flower. Honeybees foraging for both pollen and nectar are able to accomplish this transfer inadvertently by visiting multiple flowers, with more visits to an individual flowers increasing seed yield. After pollination Meadowfoam is left to mature while seeds develop and the plant matures to a golden color. Meadowfoam is harvested in a similar manner to grass seed with the fields typically being cut and windrowed in late June. After a week of drying, seeds are separated with a combine with reported yields ranging from 400-1200 lbs/acre, with lower yields generally being attributed to poor weather during pollination.

The shape of Meadowfoam flowers encourages foragers to get deep into the flowers facilitating the inadvertent transfer of pollen by bees seeking nectar

Beekeepers that pollinate Meadowfoam harvest supers immediately after pollination to produce a high quality monofloral honey that is unique to the Willamette Valley and fetches a premium retail price at local markets. Meadowfoam honey is amber in color and has a very distinct ‘toasted marshmallow’ flavor that is unlike any other honey I’ve come across.

Further information about growing and pollinating Meadowfoam are available at these links.  and


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