At Level 22 the Wild Rose Bed becomes available to us, produces Rose Petals, and enables us to complete both the first part of Magnus' Making Scents quest, as well as Part 2 of Bluebelle's Asking the Oracle questline. To find out more about Rose Petals specifically, such as their pricing and the recipes in which they're used, check out the page about Rose Petals.
You will likely be purchasing your first Wild Rose Bed around the same time that you claim the land underlying the Myra's Potions & Perfumes market. Once you have both of these available to you, Myra will begin asking you to sell her Rose Petals. I would advise you to take advantage of this for as long as it is available to you, because it is a great way to level up more quickly!
While I wouldn't make this my only method of leveling, if you're already in the game, satisfying a Glurb or Liang request, or just crafting stuff to sell to Myra, make sure you collect your rose petals every time they ding, and then immediately sell them to Myra. She pays 22 RC and 39 XP every time you sell to her. This works out to 1170 XP per hour, with the nice side benefit of earning you 660 RC per hour as well!
2 Rose Petals
Available to buy at level:
First: 45,000 royal coin, 30 crowns thereafter
Time to build after purchase:
Maximum number per kingdom: