What plants are poison to bee's ?

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punky3612

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I understand that alkaloids in rhododendron nectar are poison's to humans but what plants are poisons to bees?
 
I understand that alkaloids in rhododendron nectar are poison's to humans but what plants are poisons to bees?
I have found some plants that are toxic to bee's. Various plants are known to have pollen which is toxic to honey bees, in some cases killing the adults (e.g., Zigadenus), in other cases creating a problem only when passed to the brood (e.g., Heliconia). Others plants which have toxic pollen are Spathodea campanulata and Ochroma lagopus. Both the pollen and nectar of the California Buckeye (Aesculus californica) are toxic to honeybees,[23] and it is thought that other members of the Buckeye family are also.
 
I have found some plants that are toxic to bee's. Various plants are known to have pollen which is toxic to honey bees, in some cases killing the adults (e.g., Zigadenus), in other cases creating a problem only when passed to the brood (e.g., Heliconia). Others plants which have toxic pollen are Spathodea campanulata and Ochroma lagopus. Both the pollen and nectar of the California Buckeye (Aesculus californica) are toxic to honeybees,[23] and it is thought that other members of the Buckeye family are also.
Zigadenus paniculatus, a monocot, is a perennial herb that is native to California and is also found outside of California, but is confined to western North America
 
I have found some plants that are toxic to bee's. Various plants are known to have pollen which is toxic to honey bees, in some cases killing the adults (e.g., Zigadenus), in other cases creating a problem only when passed to the brood (e.g., Heliconia). Others plants which have toxic pollen are Spathodea campanulata and Ochroma lagopus. Both the pollen and nectar of the California Buckeye (Aesculus californica) are toxic to honeybees,[23] and it is thought that other members of the Buckeye family are also.
Ornamental Gingers and Heliconias
including Cucurma, Alpinia, Hedychium, Dichorisandra, Zingiber, Globba, Etlingera, Elettaria and Costus

This is a broad group including plants of the families Heliconiaceae, Costaceae and Zingiberaceae. The so-called "Blue Ginger" (Dichorisandra thyrsiflora) belongs to Commelinaceae. They are frequently discussed together because they're all tropical plants which produce flowers and foliage from stems that run in or on the ground (rhizomes). Most are grown for their flamboyant flowers, although the bold, tropical-look foliage is foliage is also appealing.
 
I have found some plants that are toxic to bee's. Various plants are known to have pollen which is toxic to honey bees, in some cases killing the adults (e.g., Zigadenus), in other cases creating a problem only when passed to the brood (e.g., Heliconia). Others plants which have toxic pollen are Spathodea campanulata and Ochroma lagopus. Both the pollen and nectar of the California Buckeye (Aesculus californica) are toxic to honeybees,[23] and it is thought that other members of the Buckeye family are also.
Spathodea campanulata
Common Names: African tuliptree, flame of the forest, fountaintree, fireball, Gabon tulip tree, fire tree
Family: Bignoniaceae (bignonia Family)
 
I have found some plants that are toxic to bee's. Various plants are known to have pollen which is toxic to honey bees, in some cases killing the adults (e.g., Zigadenus), in other cases creating a problem only when passed to the brood (e.g., Heliconia). Others plants which have toxic pollen are Spathodea campanulata and Ochroma lagopus. Both the pollen and nectar of the California Buckeye (Aesculus californica) are toxic to honeybees,[23] and it is thought that other members of the Buckeye family are also.
Balsa wood is a rapid growing tropical deciduous tree (Latin: Ochroma Lagopus). Main appearance: Ecuador, South-America
 
I think one of the BBKA Exam Modules might talk of three UK plants/trees being toxic to bees. I've only heard of one being toxic, and that is a species of lime tree found only very occasionaly in ornamental gardens and similar places.

I mean, any plant that kills potential pollinators ain't very clever.
 
Tilia tomentosa Petiolaris, The Weeping Silver Lime Tree. The nectar narcotises bees and they drop to the ground in a stupor to be predated by birds etc.
The ordinary lime planted in our streets and parks is more innocuous.
 
Yes, oleander nectar also harms bees and butterflies. A tenured entomologist and beekeeper from Univ of TX who showed up at the beekeepers meeting of Central TX to lecture to us about toxic oleander nectar's negative effects on hives of cultivated and wild bees. For more info you could probably contact Univ of TX at Austin's entomology dept.
The oleander plants can be pollinated and the oleander nectar is harvested by the insects just fine since it is a dilute toxin. But once it gets into hives the toxin gets concentrated because the bees dry out the nectar by fanning it with their wings. And then, when they feed the concentrated nectar (honey) to the young bees, the concentrated toxins from the TOXIC oleander nectar die, and the hive dies.

And the toxin from oleanders can also make butterflies and hummingbirds ill, if oleanders are a main source of nectar for any one butterfly or bird.
 
Several native California plants have pollen or nectar that is poisonous to honeybees, which are nonnative. These include the corn lilies, death camas and the locoweeds
 
The only UK native species I have heard to cause problems is oak: the nectar is reputed to damage the growth of bee larvae. However, as oaks are wind-pollinated I've never worked out why this would be, as of course they don't produce nectar as they have no need to attract pollinating insects.... possibly the references are confused with honeydew (which is fairly frequent on oak). One such reference is here, but I would take it with a pinch of salt:

http://www.themelissagarden.com/TMG_Vetaley031608.htm
(it's an American site I think, and the reference is about halfway down, for "English oak"). They spell "hawthorn" incorrectly, and refer to Viper's bugloss as a shrub, but on the other hand the author has obviously got their entries from somewhere and done some research.
 
I'd heard almond is toxic to bees, especially with no additional sources to ameliorate the effects, also daffodils, again raising the question as to what a plant stands to gain by poisoning its pollinators?
 
Balsa wood is a rapid growing tropical deciduous tree (Latin: Ochroma Lagopus). Main appearance: Ecuador, South-America

Most of these sound as though they are not found in the UK - would that be correct?
Louise
 
Yes, Punky's posts are not particularly relevant to the UK. Honeybees are not native to America so maybe the plants there can afford to be picky about which pollinators they support.

Rhododendron - sometimes people and sometimes bees
Usual lime trees - great honey plant in the UK, some cause problems

Almonds - the single-crop pollination of almonds by honeybees is a huge business in the US with about a third of the US stock going there in the right season. Definitely not poisonous, if unsustainable in other ways.

Daffs - honeybees don't seem interested but they do enjoy the related snowdrop. Maybe the smaller species daffs rather than the artificial monsters man has bred have their own pollinators such as bumble bees?
 
Yes, Punky's posts are not particularly relevant to the UK. Honeybees are not native to America so maybe the plants there can afford to be picky about which pollinators they support.

Rhododendron - sometimes people and sometimes bees
Usual lime trees - great honey plant in the UK, some cause problems

Almonds - the single-crop pollination of almonds by honeybees is a huge business in the US with about a third of the US stock going there in the right season. Definitely not poisonous, if unsustainable in other ways.

Daffs - honeybees don't seem interested but they do enjoy the related snowdrop. Maybe the smaller species daffs rather than the artificial monsters man has bred have their own pollinators such as bumble bees?
Very good point but most of these plants that I been researching are not native. It makes you wonder if its a problem with the bees at the plants origin.
 
I think there's research being undertaken at the moment in Newcastle as part of the previous gov'ts funding on bee nutrition, which is throwing up some strange findings, such as the almonds and how the toxicity is managed by the bees. I'd love to find out more.
 
With regards to rhododendrons, I've read that honey produced from rhododendron nectar is toxic to humans. As the gardens where I live contain lots of mature rhododendrons - just come into flower and looking fantastic - it had me somewhat worried about my prospective honey.

When I googled the subject I found a couple of references saying that rhododendron honey is said to be toxic only if very recently produced by the bees and that any produced is likely to have been consumed by the bees themselves before any honey extraction by the beekeeper. However I couldn't find anything to explain why it's supposedly only toxic when recently produced - e.g. do the toxins break down over time?

I did also come across a recipe in the Independent for spring goats cheese and rhododendron honey...
 
I did also come across a recipe in the Independent for spring goats cheese and rhododendron honey...

Is this the Indy's version of Fugu Fish for the chattering class?

Would you have taken spring honey off already?
If there is a June Gap most places would the bees just use Rhody honey for themselves?
Sorry all questions...no answers.
 
I seem to remember reading somewhere that honeybees will only forage on Rhododendron in the absence of other food sources, and that there are very few recorded cases of poisoning.

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