Should we donate our wedding flowers if guests have already been offered the centrepieces?

My partner told his grandparents they could take a centrepiece home. I had just posted that we'd donate the flowers to a local community centre the next morning.

I haven't contacted the centre. I assumed it would welcome them, then enjoyed having a nice answer when people asked what would happen to all the flowers.

Now relatives are asking which arrangements they can take. The florist has also reminded us that the glass containers are hired and must be returned. The reception ends at midnight, and nobody has agreed to pack or deliver a donation.

Would it be better to let guests take flowers and correct my post, or try to organise the donation I announced? I don't want to insist everybody honour a plan whose intended recipient hasn't even heard of it.