Here is the list of crossbreeding outcomes/how to get certain flowers:

Random Plants:
Dandelions: Randomly grows in town
Dandelion puffs: Let dandelions wither and they'll become puffs
Jacob's Ladder: Randomly grows in town with perfect town status
Four-Leaf Clover: Rarely grows in town, usually gets destroyed like withered flower when picked up

Tulips: Red White Pink Red White Red Yellow Purple Red Yellow Red Red Black Red Yellow Yellow Black Yellow   Pansies: Red Red Purple Red Red Yellow Orange Red Yellow White White Blue White