|Looking for ornamental shrubs, perennials, bulbs for attractively stabilizing riverbank. I will place precast concrete block, with holes for planting and drainage on sloped bank. Prefer a mix of plants which can be arranged in attractive design, with summer color.
|Sounds like you're looking for some bog plants. It might surprise you to know that many garden-variety plants will adapt well to really wet situations. I have Kaffir Lily, Japanese Ribbon Grass, and Primroses planted at the edges of my year-round pond. They look spectacular and don't mind having wet feet. I suggest you also try Butomus (flowering rush), Laevigata or Siberia iris, Snowball Viburnum, Marsh Marigold, Ligularia, Osmunda (Royal fern), Burnet, Lythrum (domesticated form of purple loosestrife), and Fritillaria.
There are also some forms of lobelia, forget-me-not, and geums that would fit your situation.
Try growing your favorites in containers sunk into the water. You can always rescue them if they begin to look waterlogged!