Kev, I grow centaurea through a large patch of cerastium (snow in summer), which helps support the fragile floppy stems. They both flower at the same time and look amazing.

I did wonder if it could grow through something to offer support, but the mildew and rampant blackfly are making me question its place in the garden, but the flowers are very striking
thanks
kev

Buy or construct a lattice-type of support and that works best, can't remember the company I bought from but the thing has a lattice top and sits on four 12 or 18" high struts - all plastic coated wire.

As for the aphids - I use Provado and that gets rid.

And the mildew problem occurs most when the soil is drier than the air so keep it watered but don't allow it to swamp the roots.