Posted: 12/03/2016 at 10:20
Hi Lucid, grasses are a really good choice for ponds. Many are evergreen so they're good for softening edges. Carexes are really easy and readily available. Look at Evergold. Hakonechloa is lovely and bright, though not evergreen, and makes a nice mound. Beregenias might be useful too, they prefer a bit of shade, but offer nice big leaves fro little creatures to hide under. Caltha palustris is happy as a marginal or in a damp or boggy area. No maintenance, and yellow flowers for spring.
There are ferns for dry as well as damp areas, so you'll be able to find suitable ones. The Hart's Tongue ferns are evergreen and really useful. I've always had those beside ponds I've had. Asplenium scolopendrium is it's proper name.
Don't overlook Phormiums for sunnier areas - they provide good cover and you can get loads of different varieties and sizes. Good drainage needed for them.
Hope that's a few ideas to start with