Is there even a point to collecting the flowers this year?

You can still put them on the memorial, but otherwise no, not really. I got the achievement during the year so I've just been fragging mine.

Thanks!

Slightly related question, but do you get anything for reaching the achievement? (which I believe is like 1000 flowers laid, yeah?)

Nope, just the achievement. If you get a prize, the achievement number will have a star next to it, even if it's a forum title or something and not an actual item