What are the best flowers to plant that come up every year?

You will want to check with the temperature conditions of your part of the country as well as the light but good spring flowering perennials are crocus daffodils tulips and Iris. Late spring and early summer flowering perennials are peonies which give beautiful foliage throughout the summer. Summer flowering perennials would be lilies lavender and black eyed Susan. Perennials that bloom in the fall are chrysanthemums. Many of these flowers come in several colors.

Use this site to find your plant hardiness zone using your zip code:

http://planthardiness.ars.usda.gov/PHZMWeb/

Then visit a garden center and look for perennials that are suitable for your zone. Read the tags to assure you are giving the plant the proper sun and water requirements. You will find perennials that bloom all season long in every sun condition.

BTW, just because a garden center sells a plant doesn't mean it is suitable for your zone. Make sure you check the tags.

There are a lot of good plants depending on what area you live in. Also if you want small, medium or tall flowers. Phlox is a great tall flower as is all the hardy hibiscus. I have Balloon flower, daylilies, iris, Hardy Hibiscus, snapdragons. I would suggest joining an online gardening group in your area perhaps on FB and asking them the best plants for your area.

I use bulbs like glads or lillies because not only do they come back every year, if you fertilize then well, they make new bulbs that can be split and planted in other places

Your location and lighting is needed for advice

In my area of the Midwest, lilies work wonders. I love them for coming back bigger and better each year. :-)