You've got me stumped, no idea what a "Toby" is. But I believe the description hop "garden" comes from the time when the church took Tithes, or 1/1th of a farmer's produce to feed the monks.
As I understand, this only applied to crops grown in the fields, not the garden. So they got round it by growing hops in gardens. I believe this originated in Goudhurst. I could be wrong and am quite happy to be corrected.