Subject: Re: Scientists added nutrients to bee pollen
Plant herbs, such as lavender, oregano, rosemary, thyme, borage, sage and catnip and let them flower. Plant fruit trees. Plant berries, such as blueberries and raspberries. Plant goldenrod. Bumblebees will come to these. They aren't hard to grow.
Go to local plant nurseries and follow the bees. I recently bought Penstemon 'Catherine de la Mare' because the plant was literally buzzing with bumblebees at a plant nursery. I'm propagating it from stem cuttings which will come true to variety and are easier than growing from seed.
Wendy