The honeysuckle or beewort; or perhaps the convolvulus.
Where the bee Strays diligent, and with extracted balm Of fragrant woodbine loads his little thigh.
So doth the woodbine the sweet honeysuckle Gently entwist.
Midsummer Night's Dream, iv. 1.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894