Hey loicdufresne

This thing in the middle of the roundabout (https://www.openstreetmap.org/way/1181261285) is most probably *not* a garden: "set aside for the display, cultivation, and enjoyment of plants and other forms of nature" (as steted in the OSM Wiki) but should be mapped as https://wiki.openstreetmap.org/wiki/Tag%3Atraffic_calming%3Disland

This 'smells' of tagging for the renderer, so that the island shows up as a green circle in the middle of the roundabout. Please try to 'abstract' the stuff you see on the ground into correct OSM tagging.

Greetings from Bern,
habi