Good water control plants?

maple trees, Japanese maples if you need small ones.

Yellow iris pseudocorus, wild blue flag, Siberian Iris, March marigold loves mush, Mountain ash (a small tree with red berries), cedars (like wet feet), for shade, primroses if she is zone 5 or south.

There are a great number of people who can assist you with your plant question. If I may adress your fence? Have you tried a base of whiterock tamed into half the depth of the hole (this allows drainage and sets up like concrete) topped with sand? The secret is to tamp the hell out of both medium. Really, you can’t hit it hard enough and don’t forget a crown. No matter how hard you hit it it will settle.

You might want to google “rain gardens” to see if there are any native plants listed that are suitable for your planting zone.