Finding Out about Airfields

Every so often I come across something in my home area that I didn't know about.  Today it was a museum commemorating the New Forest World War Two airfields.  I knew there were a lot scattered around, plus various military establishments, including the one my father worked for.  But because my parents didn't talk much about the War, I'm belatedly finding out some of the things that happened.  The museum was situated on an old airfield (only Bournemouth Airport has stayed with its original use).  On the way home I stopped off at a Pick Your Own, because what photographer can resist a field of sunflowers?  That, I learned, was another old airfield.

I rarely go to a PYO, but they always seem to have sunflowers.  Does anyone know why?  Apart from attracting the attention of idle passers-by, of course.