
Juncus (likely)
A clump of rushes in the deep middle area of the pond. Likely a Juncus (rush); species tbc.
Rushes give dragonfly and damselfly larvae something to climb out on. Most prefer shallow water over the crown, so if it starts to sulk, raise it up on a brick.
Upright foliage within the pond display. The suitable position depends on confirming the rush species.
Healthy clump of rushes standing in the deeper middle section, with some underwater stems and a little feathery submerged growth around the base.