Sweet William, Pennisetum and Rudbeckia sown

Only a couple of the sweet william sown on  19 March have germinated, and none of the rudbeckia sown the same day have come up (all of which were seeds saved from last year), so  I've sown some more. I also sowed some pennisetum seed that I saved when I cut the pennisetum back on 15 March - no new growth showing yet).