Head westwards from zonein to that little island building. I'd suggest the group sets up in the small walled-off courtyard before you enter the building itself. No roamers through there, and only one corner respawn to deal with. (Though if you get a lucky instance, some of the corner spawns won't be there for the entire time.)
Anyways, the first named is up when the instance appears, the Goblin Gardener. He tends to roam around the outer hallway in this building. Hits relatively hard, and flurries if I remember rightly. He drops the pot (a container to combine the rest in.)
After about 30 more trash kills, the Something Messenger will spawn, emote, and walk from somewhere in the back of the building into the garden to check on the Lady. Also tends to hit hard, and was pretty magic resistant if I remember rightly.
Kill him for the fertilizer.
Now, the flower is inside the central little garden area of the building. Best approach is from the South by an invis class that cons everything carefully (some of the drakes and kirin will see invis,) or an FD class.
Run inside the room, and FD or crawl towards the far (North) end of the closest (South) of the three planters in the middle. On a dark green leaf will be a small red and white mushroom looking thing. That's the Lady. Pick her up, combine with the other two, then take it back to camp for the win.
Pretty easy event with either a good tank and healer, or a good kiting team can take on the named, since they do not summon (yet.)