Rhododendrons are a genus of flowering plants found primarily in the northern hemisphere and introduced to Britain in the late 18th century. Some types are now a pest in Britain, because they out-compete many native plants and, because their leaves contain toxins that some animals find inedible, their spread is hard to control. Honey made from rhododendron pollen or nectar can cause hallucinations, loss of co-ordination and vertigo, but only if it has been made by the bees very recently. This is known as mad honey disease!

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