Frost has killed off all the buds? late frosts can do this

There weren't any buds on the rhodedenrum. The lilies sprouted early with good amount of foliage but no flowers at all.

Agapanthus aren't reliably hardy, I'm afraid, so if there are no leaves appearing by now, it looks as though you've lost them.

No idea why your lily of the valley came up with no flowers - why not give them a feed at this stage, to boost them for next year.