A classic summer flower, the sunflower is a great bloom to use in summer bouquets or to grow in your garden. Specifically the annual sunflower (Helianthus annuus) is the flower most people picture when they think of a sunflower. Sunflowers are a favorite for many people because of their beautiful range of colors, showy size and generally happy (and sunshine-y!) appearance.
Sunflowers are great in flower arrangements because they are large and showy, but also because they are hearty with thick stems that stand up well in a vase.
Sunflowers, even within the single classification of Helianthus annuus show a wide variety of colors, shapes and uses. A sunflower can range from the bright, cheerful yellow that is most commonly recognized, to chocolate brown and even purple shades. In addition to a wide variation in color, sunflowers are also recognizable for their potential to grow very large - up to 20 feet tall and with a bloom over two feet in diameter, according to Gardeners Net.
Below are a few examples of the many colors and shapes of sunflowers. When planning a summer bouquet of sunflowers or event request with your florist, you might ask what varieties of sunflowers they can get from their flower providers.

A bouquet of sunflowers in a variety of colors shows the great range available.
(Photo (c) by Jean English for The Maine Organic Farmer & Gardener, www.mofga.org, used with permission.)

Two varieties of sunflower. Left: Moulin Rouge, a red sunflower. Right: Tokohuyae, a double flowering sunflower.
(Photo (c) by Jeanine M. Davis, Ph.D., www.ces.ncsu.edu, used with permission.)

Two more varieties of sunflower. Left: Ring of Fire, a bi-color sunflower.
Right: Teddy Bear, a compact double flowering sunflower with no 'eye'.
(Photos (c) by Jeanine M. Davis, Ph.D., www.ces.ncsu.edu, used with permission.)
Being native to Central American and found wild as far north as Tennessee in the USA, the sunflower is obviously a hearty plant that can be grown easily with moderate care. Sunflowers usually bloom in late summer, so expect to have flowers starting mid-July or later and often lasting until September. Growing instructions will vary somewhat based on the type and size of seed you choose to plant, so turn to resources like Burpee or other seed companies.
Sunflowers have a very special property called heliotropism, which just means that as it grows, the sunflower turns its face to the sun throughout the day. In the morning, the sunflower's bud faces east to catch the rays of the rising sun and by nightfall, the bloom is facing west to capture the last sunshine as the sun sets.