There are 3-4 Windwheel Asters each location, and you can get around 30 in total.
You can get about 14 Windwheel Asters.
Mondstadt Region Puzzles, Secrets, and Hidden Chests
Puzzles, Secrets, and Hidden Chests in Dragonspine
How to Beat Monsters/Farm Enemy Drops
Crystal Core Farm Locations
Xiao & Invitation to Mundane Life Event Wish
Ganyu Event & Adrift in the Harbor Wish
Top Mining Spots in Dragonspine