I did this but it does not seem to make any difference on the progress.
I used the galleria on night raid for buried city and the area between the 4 launch areas and towards the end on the right as well.
Ill give dam a try.
Galleria used to be great, every single potter filled, but I think they nerfed the spawn rate in there.
You still get lots, but I havent seen it packed like it used to be.
If you circle around the edge of the map you'll find great mullein and agave you can harvest in any area with trees as well.
There's an area at Outskirts near Merano station that has lots of great mullein, top left of map.
And of course there's quite a few spawns in the Park if you're careful.
The bottom floor of Research on the corner facing the park there are usually a few spawns in planters similar to Galleria (but much less) this has also been nerfed tho.
I got 20k on buried city on a night raid but that was with another person and we were each making a sweep in opposite directions around the map.
It should be straight forward to get three stars solo, but it does depend on if anyone else is chasing the same loot and if you have to worry about PvP or not.
Theres also some great mullein near Grandioso apartments, by the flooded solar panels, around the edge of the water.
I know I've missed places, but that lot should do three stars if it's easier to go buried city night raid.