[thedoc (OP)]

christina swartbooi asked the Naked Scientists:
   
How does the sunflower have an effect to the environment

What do you think?

[CliffordK]

Like any plant, they photosynthesise, and produce plant matter from carbon dioxide and various nutrients. 

Honeybees seem to really like the sunflowers, and have a long blooming season.

They have edible seeds and can be used to produce oil (biodiesel?).  The stalks may appear substantial, but not much is left after they dry out.

I have seen wild sunflowers in Idaho that seem to take very little care.  The large "domesticated" sunflowers seem to like a lot of water and fertilizer.  With that in mind, perhaps they aren't optimal if used primarily for aesthetics. 

Do you have any specific concerns?

[Don_1]

They do create something of a problem in that they are rampant self-seeders and grow to quite a height.

Yes they are a very bright and welcoming sight, perhaps even entertaining, in the way their heads track the Sun's passage across the sky, but any gardener will tell you they can be right pain in the borders if you don't remove the flower heads before they start spreading their seed. A neighbour once planted a giant Sunflower in their garden and left it to self-seed. They had them all over the place the following year and we were pulling up young plants almost daily to prevent being overrun by them.