My favorite clematis is generally whatever is blooming in the moment, because they are all awesome at that point aren't they?
However, I have only recently 'discovered' the non-vining ramblers and small flowered varieties and I have been really impressed so far with how these new (baby) plants have performed in their first season. Hands down, my favorite is 'Arabella', for non-stop bloom spring-summer-fall, even in the shade.
'Trikatrei' put on the best show for sheer number of flowers, and outgrew it's temporary trellis. Hopefully, it's companion rose will eventually grow up too.
My favorite color and shape is 'Rooguchi'; second favorite color is 'Venosa Violacea'--but I didn't take a decent picture of either.
'Madame Julia Correvon', 'Maria Cornelia', and 'jouiniana praecox' were stellar, but I neglected to even attempt a photograph to prove it, for some unknown reason.
I had quite a few snail casualties and others are still settling in and thinking about flowering next year, but here are a few more pics of some new ones for me this year:
'Juuli'
'Pamiat Serdtsa'
'Durandii'
'Moonfleet'