An orchardist is a building made the Patron to manage meadows. Once it has been built, employees can be hired and assigned to produce honey or fruit. As long as you own a nearby meadow which has been assigned to produce that product, your employees will go to the appropriate meadow and do so.
An orchardist is helpful when building a Public House since it can provide fruit for alcohol. It's also helpful when building a Bake Shop since it can provide honey for biscuits.