I’m running Overbourn Marshes so here’s a thread for a bit of info.
Lore: At the southern tip of the Old Forest, on the eastern border of the Shire, the River Brandywine was met almost simultaneously by two other rivers. The Shirebourn flowed into it from the west, and the Withywindle ran down to meet it through the Old Forest to the east. The three rivers met at the southern end of Buckland, and the sudden inflow of water resulted in a region of marshland to the south of Haysend and Deephallow. This region was known as the Overbourn Marshes, and it spread out southwards from the meeting of the three rivers.
 Birch leaves as bushes.
 Two blocks high reeds.
 Tussock grass.
 Double tall grass.
 Wavy hair plant
These plants tend to grow in clumps, so see what has been done already for examples.
Important: I’ve gotten some tips from wheellee so here goes, the wavy hair plant should be dense patches in most cases, it can be in smaller patches but in general it should be, use the tussock grass to blend the tall wavy hair plant into other things. Bullrushes should be prominent in muddy areas, reeds using better foliage and lilypads near the banks in sheltered areas. Birch leaves for bushes should only really be in the centre of islands, not too close to the banks.