Rose gardens serve as a fast travel teleporter from one part of a region to another in the same region. When you come across a rose garden, wading in the water surrounding the tree in the center will whisk you off to a floating island near the Oak of Ages. Step out of the gazebo and into the next and you may be teleported to another part of the region you came from. However, be warned.

The gardens in each region have a chance to send you to the bog (or worldspawn from the Ruins) instead when you use this method of travel.

The chances of being sent to the bog (or worldspawn from Ruins) from each region are as follows:
Ruins 40%
Sands: 50%
Mines: 60%
Halls: 70%

When stepping onto the pressure plate in the gazebo, be sure that your entire group is standing on the gazebo platform before activating it, or you may be separated.