Each year's set of buds should all be appearing at about the same time. With it being a good idea to snip out spent leaves each spring for cultural reasons and not just aesthetics. Otherwise if it appears the plant might be diminishing try fertilization* and mulching.

*If you have a number of different plants that may not be up to par, are producing specific hints like poor foliage color and subpar vigor sampling your soil and having it analyzed would be a good idea

like any crop.. flowers vary from year to year ... and there are just so many variables it hard to say why ...

stepped on during fall cleanup ... bad winter ... too mild a winter ... which are sometimes worse than bad winters ... squirrel tried to dig it up ...

i mean i could just go on and on ...

perhaps if you added a pic.. even more reasons might pop up ...

even a damaged leaf can convert sunshine into energy ... but if there are plenty of new leaves emerging.. no need to leave the ugly ones there ...

ken