Perennial plants that provide nectar include yarrow, coneflower, joe pye weed, lavender and sunflowers. Many plants considered weeds also provide nectar, including clover, thistle and dandelions. Fortunately, many of the same plants that are useful for butterflies are also friendly additions for birds. Many common flowers, if allowed to go to seed, can be excellent food sources for birds. Plants that attract goldfinches include black-eyed susans, purple coneflower and wild thistle.
Many shrubs also develop berries that are important food sources for birds.
An added advantage to the vegetable gardener is that many flowers and herbs attract pollinators such as bees. In our garden the raised beds where we grow vegetables are surrounded by herbs that, when flowering, are a powerful draw for bees and other insects. So, if you want to attract birds and butterflies to your garden don't overlook the many 'ordinary' plants that can help you. And don't be too overzealous in cutting dead flowers or pulling up every weed. Today's dead flowers are tomorrow's bird seed.