Conversation so far:
When did William Bartram return to Philadelphia?
Bartram returned to Philadelphia in January 1777.
Where did William Bartram return to Philadelphia from?
William Bartram returned to Philadelphia after exploring Cherokee nation.
What did William Bartram do on his return to Philadelphia?
William Bartram assisted his brother John in all aspects of running Bartram's Garden.

Question: What types of things did he do for the garden?
Self-contained rewrite: What types of things did William Bartram do for Bartram's Garden?