Stinking hellebore is an unappealing name for a very bee-friendly plant. It has been the epicentre of bumblebee activity in our garden ever since they first emerged from winter hibernation. The green flowers of Helleborus foetidus are a prolific source of nectar over a prolonged flowering period.
There used to be just one plant in the garden but three years ago I collected all the seed it produced and chucked them on ground where I'd removed a holly hedge in the corner of the garden. There are now about a dozen plants flowering, bearing hundreds of flowers. They don't really stink, they're just a bit pungent on a hot afternoon, but that's a small price to pay for providing such a good food resource for queen bumblebees.
The purple-edged, bell-shaped flowers are unusual because those structures that look like petals are, botanically, sepals that protected the bud during its formative stages. The real petals, inside, are arranged around central whorls of stigmas and pollen-loaded stamens, and are rolled into tubes that are prim-full of nectar.
The flower retains its bell-shape until its pollinated but it's just open enough to allow a large bumblebee to hang underneath and force its way in. Even then, the bee needs to have a long tongue to reach all the nectar. Helleborus foetidus makes its visitors work for their reward.
If you plant Helleborus foetidus once and let it go to seed it will seed itself around the garden,
thanks to the white extension called an elaiosome on the outside of the shiny
black seeds.This is very attractive to ants, which carry them away, eat the
elaiosome and disperse the seeds, which require a winter of freezing
temperatures before they'll germinate.