Top bee magnets in my yard--what fun to think about this!--I'd have to say:
for spring to early summer: penstemon (species), cosmos bipinnatus, monarda fistulosa, spirea japonica, lavender
for midsummer: salvia 'May Night', agastaches, yarrow, sunflowers, basil 'African Blue', catnip, cosmos sulphureus
for late summer to early fall: caryopteris, calamentha nepeta, celosia plumosa, fennel blooms, sedum 'Autumn Fire', aster 'Purple Dome'
