There are many plants that will grow in wet / moist soil as that is there natural habitat however, to get a decent show from these plants you would need to prepare the soil for these type of plants just a s you would with any other type of garden plants.
To do this, you need to add loads organic matter to the soil And plenty mulch for when the soil dries out in summer I take it this drying out happens in summer??.
Plants that grow in wet / damp pool edges are wonderful in both colour and different textures, I may be the odd one out but, I don't think you need ALWAYS have flowers to give a great show, different shades and textures of green can give a breathtaking display.
The other trick for your situation is when you plant leave a shallow indent at the planting soil around the root area so that when it rains or you water, this little basin will collect water instead of it running off the surface.
You should go to the local library or book store to read up on either wetland gardening OR pond / pool edge gardening, they will give pictures and planting ideas as to groups of plants for you to look at to give ideas.
A list of plants that work well are:
Astilbe, (red, white, pink etc)
Hostas, lots of different colour's of green / white .yellow edged leaves and purple flowers, they grow into large clumps.
Iris, there are some beautiful Irises that can only be grown in damp / wet soil, I have a large clump of Yellow tall iris that never seem to disappoint me.
Primulas, again, lots of different ones to look for, tall, small and stunning.
Ranunculus, stat to flower spring,
Trollius, again start in spring,
Rogersia ? large leaf looks like a chestnut shape leaf, white / cream flowers,
Arum Lilies, these are beautiful, large white, ruby, pink or green flowers, huge heart shaped leaves, cant remember the real name it might begin with Z,
These are just a few plants off the top of my head or grow in my wet area of garden, West Coast of Scotland is almost always wet ha, ha, ha.
but you could have an area the envy of many with the conditions you have so I would say before you spend money on the wrong plants, research what you need to make a wetland area, it will be beautiful in time IF you do it right.
Good luck, WeeNel.
