Sir Walter Seed Heads

Why has my Sir Walter lawn gone to seed?

It is part of your lawn’s survival mechanism in response to change.
Change such as sudden hot weather or lots of rain.

If your lawn is going to seed only during these sudden changes:

You have nothing to worry about.

If your lawn is constantly in seed:

You probably have some issues with your soil.
You will need to take some remedial action such as fertilising and top dressing.