Helianthus mollis "Downy Sunflower" This picture is from "Annie's Annuals and Perennials" at www.anniesannuals.com A native Midwest perennial sunflower rated for Zone 4.
The annual sunflower needs no other help besides feeding your birds sunflower seeds in the winter or a quick throw of some seeds in the spring. Or, plant if you want them in specific spots. I have them sprout from many places and some are pulled because a plant would cause problems but most are enjoyed as a surprise treat.
This is the time of the year when sunflowers come into their own. When most other flowers have finished blooming, a sunflower puts on a show to brighten the landscape and feed the beneficial insects. A field of sunflowers is a beautiful sight as they face the sun with military precision.
In late summer after blooming, the annual will typically have untidy leaves (they may mildew), sometimes bend over from the weight of the head and turn brown. Either pull the plant and cut off the head to dry - or - let it dry on the stem and you will be rewarded with American Goldfinches hanging upside down plucking the seeds. I sometimes do both. Once the cut heads are dry, I lay them outside where I can watch the birds. You can also save the dry seeds and use them in the winter.
Other perennial sunflowers and false sunflowers are more garden friendly but most will gradually increase in clump size so read & plant accordingly. They are ideal late summer cut flowers.
Both annual and perennial sunflowers have been hybridized and size, color and form are many. Not only the beautiful golds, but, now there is maroon, lime green, bright yellow, doubles, frilled, and more. Size of flowers vary and plants are dwarf to ten foot high.
Bees love both the annuals and perennials although they don't frequent the doubles as much. If insects intrigue, you will be amazed at the many different kinds of bees these attract. From a tiny little bee to the large bumble bees. Some are red, others metallic green, and fortunately the honey bee.
Speaking of bees: I have never been stung by a bee unless I've accidentally trapped it on my person (such as bending my arm as it sat on the elbow curve.) I can work in my garden with them buzzing all around and they ignore me. I am simply aware and try not to bother. I also keep children out of those areas during heavy blooming.