Is there a local nursery with a designer that can help you decide? (Not big box stores)

Here are a few ideas:

Try this behind your garage: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=443503&isprofile=0&;

The point of a rain garden is to help dissipate runoff from rain. Where so your gutters drain to?

Do a bit of garden at a time. It helps to have an overall plan. This can be pretty vague, like more shrubs in the border by the fence. What I'd do is put a bunch of small, understory trees like dogwoods, redbud, silverbells along the fence. Then, I'd add a bunch of flowering shrubs. I'd focus on smaller plants in the raised bed, unless you're plannng veggies.

I love Doug’s ideas. That said something on that scale requires a lot of work. So,unless you’re planning to use professionals, the easiest way is to do a couple of beds at a time. Focus on what seems most important to you to change, cutting beds, planting trees or whatever and add to your garden over time. Good luck!

debra

A rain garden should not be next to a structure. The water could damage the foundation or cause wood rot.

I hadn't heard the 10 foot rule but that would be a minimum and you have more room to make it further than that.

With clay soil especially the water will stand around before seeping into the ground.

The plan you provided is nice but no one can tell from a photo the grade of the lot or where the surface and downspout water naturally flows to or can be directed to. You need to determine that first and then place your rain garden there.

There are lots of water loving plants...Iris I think like boggy ground. Ask a local nursery as suggested.