Hi Chef,
When a Friend requests help in reviving the Tree or Bush in their Backyard, you will be notified of the same at the Chef Circle. You can help them by following the steps below:
You will see a red notification on the ‘Chef Circle’ icon at the bottom right corner of the screen
Goto the 'Help' tab to see the list of Friends seeking help
Visit the Restaurant of the Friend you want to help
Find the withered Trees and Bushes in their Backyard.
Tap on the Tree or Bush with the help icon over it to help to revive