I prefer perennial flowering plants.   While they don’t require replacing every year, it sometimes takes years for them to establish themselves and produce well.  And some years are more plentiful than others.  A dozen years or so ago, I planted 3 clematis … a red, a white and a blue.   I mistaken thought that they would bloom together since they all were labeled as early summer bloomers.  That has never happened.  None of them bloomed at all the first year – I had not really expected them to.  The next year, I had three vines … the blue was fairly nice looking and produced several blooms; the white produced almost as much vine, but only a couple of blooms; and the red was nothing but a scrawny vine.   Most years since, the blue has produced a lovely vine-covered for 3 or 4 weeks with blooms,  the red have taken turns.  Actually, the red bloomed the last two years in a row and the white didn’t produce a single bloom.    Maybe it was the cold, cold winter … or maybe it’s mother nature making up to me the lack of tulips after then cold, cold winter, but all three vines are nice and full.  The white is blooming and there are buds on the red that probably will not open until after the white is finished blooming.  The blue doesn’t show any buds yet, but I’m sure they’ll show up soon.