Wolfhooks can be found under trees near Wolvendom. Sometimes they are hidden in bushes. Use sword unit to cut bushes out.
You can get 20 or more Wolfhook here.
You can purchase Wolfhooks from Botanist Chloris. The refreshes every 3 days and the items don't change. You can't see her at night.
Puzzles, Secrets, and Hidden Chests in Liyue
Puzzles, Secrets, and Hidden Chests in Dragonspine
Top Mining Spots
Time and the Wind Quest Guide
Primordial Jade Vista
The Great Mountain Survey Quest Guide