M L H
(Mountain Laurel Honey)
This year when I was extracting my first crop of honey, I thought I was very lucky for my bees to
have made so much in such a bad frost year.  It was so beautiful, light and clear, that I could hardly
wait to work it.  One of my perks for extracting is that I get the first sample of my honey - imagine
my surprise when that first taste was so bitter that I spit it out in the honey barn sink!  I nearly
cried when all that honey turned out the same way - so very bitter and bad tasting that even my bees
would not go back to the two frames I had uncapped, preferring the current nectar blooms over that
bitter honey.  
Here is the information and references I have been able to find about what happened...
(From the NC Bee Buzz, vol 33, no 3, Fall 2007, page 9)

Dr. David Tarpy, the NC State Apiculurist, writes that this bitter honey has shown
up in North and South Carolina, Tennessee, and Georgia.  When samples of it were
analyzed by a leading expert in pollen identification, it was found that the
"overwhelming majority of the pollen found in the sample was laurel, strongly
suggesting that this is the source of the honey" (page 9).

Because of our late freezes and continuing drought this year, the early nectar plants
were not good, forcing the bees to work other things that were available - mountain
laurel for example (remember I was surprised to find my bees working the red azaleas
in front of my home? that was not good...)

Dr. Tarpy tells us that mountain laurel contains something called
grayanotoxins that
are harmful to people if we eat enough of them.  They affect our nerves cells and
other organs and tissues, causing weakness, slow heart beat, perspiration, nausea, and
can even kill you in high enough doses.  Dr. Jeff Harris at the USDA Baton Rouge
lab says a "potentially lethal dose for humans is 3 milliliters of laurel honey per
kilogram of body weight."  This is about 14 tablespoons for a 150 pound person.  It
has to be in a fairly short period of time though, because the effects usually wear off
within 24 hours (still on page 9).

They say that if your honey tastes bitter, do not eat it or sell it, save it and feed it back
to your bees as winter feed.  It will not hurt them (last bit from page 9).
Jaycox, Elbert R. (1982).  Beekeeping Tips and Topics.  Modern Press.  Alburquerque, New
Mexico.  Article of interest (
Bees, People, and Poisonous Plants) is on pages 105-107.

Mr. Jaycox writes that toxic honey is produced all over the world, Turkey, Japan,
Greece, New Zealand, Scotland, South Africa, and the US.  In 1965, T. Palmer-Jones
did a thorough review of the subject in the
New Zealand Medical Journal.  "...Honey that
causes vomiting, dizziness, and even death was well known before the time of Christ"
(page 105).  People then knew that this kind of honey was associated with plants from
the
Rhododendron and Azalea families.

These plants are the most common form of toxic honey in the US.  They grow wild and
are cultivated all over the country.  In 1969, this toxic honey (mountain laurel,
Kalmia
latifolia)
was implicated in Washington state as having made some people sick (page
106).  

"In some cases, the bees do not normally visit the particular ploant but do so because
of the failure of other plants to bloom at their ususal time.  Nectar that is toxic to
humans but not to bees is often consumed for brood rearing early or late in the year or
is used only for winter stores, so that none of it is taken from the bees" (page 107).
Atkins, E. Laurence.  (1997) Injury to Honey Bees by Poisoning, article from the Hive and the
Honey Bee
, pages 1153-1208.  Dadant & Sons.  Hamilton, Illinois.

Mr. Laurence tells us that honey from mountain laurel (Kalmia latifolia) is one of the
two types of honey that can hurt human beings, the other being from a honeydew in
New Zealand.  

"
The mountain laurel, Kalmia latifolia, is found from southern Maine to Florida and Louisiana on
rocky hillsides and acid swamps.  The plants contain a poison andromedotoxin which poisons and
sometime it occurs in honey.  After eating a spoonful of such honey, people may feel numbness and
may lose consciousness for several hours.  No aftereffects have been reported (Lovell, 1956)" (page
1195).
Honey Plants.  (2007). Article from the ABC & XYZ of Bee Culture, pages 398-444.   A.I.
Root Company.  Medina, Ohio.

Page 440-441, section on Rhododendron.  Here we find that plants from the heath
(
Ericacceae) family are recognized as sources of toxic honey.  There is a story about some
Greek soldiers in 401 B.C. who are supposed to have died from eating toxic honey from
the
Rhododendron ponticum plant.  This article says that laboratory tests confirm that several
species from this family are poisonous to bees too.  The experts suspect both the pollen
and nectar and believe that the toxicity is dose-related or has a delayed effect.  They also
think that perhaps the toxins are dilute in nectar, becoming more concentrated as the
moisture is evaporated out in making the honey.

Page 441-442, section on Mountain Laurel.  Mountain laurel grows in the moist
woodlands of upper elevations of the Appalachians.  All parts of the plant are harmful to
people.
This is what I was able to find in my bee books about toxic honey, mountain laurel,
and rhododendron.  If you have anything to add, e-mail me at
pcbeekeepers@yahoo.com

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This is mountain laurel taken
on our property in June 2000.
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