Posy Poser

Wanda's partner is Mitch (clue 1). She didn't receive roses (clue 1) gladioli (2) or lilies (3) so asters. The woman who received gladioli from Matthew wasn't Wendy (2) or Wynne (3) so Willow. Wynne's lilies weren't from Mark (3), so Mike. By elimination, Wendy received roses from Mark.
Thus:
Wanda - asters - Mitch;
Wendy - roses - Mark;
Willow - gladioli - Matthew;
Wynne - lilies - Mike.