The scrub removal was carried out in 2011 but it has taken until now for the benefits to be seen as the plant takes two years to flower from seed, he said.

BBC: St John's Wort boosted by Gwynedd cliff scrub clearance

His reconnoitre had led him, through a vegetable patch given up to weeds, into what had been a garden, its single remaining flower bed marked with seed packets that told what its several rows contained.

NEWYORKER: The Woman of the House

What they found was that pollination rates were vastly reduced on the mainland with seed production per flower 84% lower compared with the islands.

BBC: New Zealand scientists record 'biodiversity breakdown'

They looked down at the solitary flower bed, at the bright-colored seed packets marking the empty rows, each packet pierced with a stick.

NEWYORKER: The Woman of the House

In the flower beds, coneflowers such as echinacea and rudbeckia turn into food as the blooms go to seed this time of year.

WSJ: Giving Birds a Refuge--WSJ Weekend Gardener