rain garden questions
My husband and I are brainstorming about designing a large rain garden on our property. I'll try to paint a picture:
Our property is rolling, at least by Central Ohio standards. The house sits at more or less the highest point on the lot. It slopes down both front and back. The driveway is 110' long, and is on the right (east) side of the lot, and as you turn in, it goes briefly up just slightly from the street, then slopes down, then back up towards the garage. This low point, which is about halfway up the drive, mostly drains to the right (east) as the land slopes back up towards the west. One of our downspouts (that drains about 1200 square feet of roofline) also drains here.
The area in question is at the far east side of our property but is more or less contained within it. To give you an idea of the amount of water - a 0.25" quick thunderstorm will usually result in standing water an inch or two deep in this area that takes maybe 2-4 hours to soak in if it isn't already saturated. If we have a big, all day rainfall event, the 1-2" kind, it can stand in water for a couple days. In winter it usually runs pretty saturated. In summer, it is usually dry enough to walk on unless we've had a lot of rain. If there's a drought it can get as dry as the rest of the yard. The water table is only about 12-15" down at the peak of summer.
With only a small berm around part of it, we figure we can make an oval about 70 feet long and 30 feet wide. The long part would be oriented north/south and the narrow part east/west.
My idea here is to have the back side (from our perspective contain some taller plants, probably trees. Shrubs and perennials in front to create a nice tiered appearance.
What are some good plants for this situation? We're in zone 5B, near Columbus, OH. Soil is a clayish loam, neutral pH.
My main concern is salt - if we salt our driveway during winter storms, would enough salt runoff accumulate to kill our rain garden?