oops! The area gets full sun all day.

Japanese and Louisiana Iris. Though they won't bloom all season...
Gerald Darby -which is Iris Robusta also likes water and it has foliage that starts out purple, then turns green before it blooms, but the stems are deep purple then. It's very interesting looking.
You could perhaps mix it with another iris of a complementing color or different bloom cycle.
Sweetflag- which is more like a grass and doesn't bloom has interesting foliage.

This post was edited by lola-lemon on Thu, May 16, 13 at 18:18

Nice suggestions. I was scouring the web and came up with Queen of the Prairie and swamp milkweed, which I ordered. I think Siberian Irises also like it moist/wet. I'm thinking now to put the irises with the grass you suggested on the other side of the ditch. Thanks lola-lemon.

Also monarda, turtleheads and astilbe all like extra moisture, and will do well in full sun provided the soil stays wet. Some primulas will like the moist soil, tall phlox will do well..... But unless you seek out a dwarf version they might get too tall for what you want. None of these will bloom all season, the phlox will probably give you the longest season of color.

All good choices. I may have to expand to include more along the ditch and not just around the mailbox.

Thanks kato_b

You need to be a bit cautious in your choices :-) Plants that are often listed for moist sites typically have a real preference for what time of year might offer that moisture. For example, there are a great many more plants that will tolerate "wet feet" from periodic flooding in spring and summer than those that will tolerate similar conditions in winter.

Most of the plants listed above will be happy in rather wet conditions during the growing season but may not survive a winter under similar circumstances. That is a much shorter list :-)

Here is a link that might be useful: Plants for wet sites

Louisiana and Japanese Iris will grow in a boggy area or even submerged in a pond year 'round. I have both in my ponds. They don't bloom long though...

If by Queen of Prairie you mean Filipendula rubra: 2 feet? You have to expect 2 meters rather. And a lot of acreage. It will devour its neighbors for breakfast in one bite.

Helenium would be another choice, but they can get quite tall at four to five feet, and start blooming in late summer. Lobelia likes moisture but if the area dries up in the summer, extra watering will be necessary. They don't like drying out.

Karen

For future reference, I have a very wet spot, also and Leucothoe Rainbow and Bowles Golden Sedge are doing awesome there. The Leucothoe you can keep to any size you like, it loves to be trimmed and a lot of people use the greenery as backdrop filler for arrangements in their home. Lots of color for a shrub! The sedge is a short yellow-toned grass. Love, love the contrast that I get with it. These might work for you in this or other wet areas.

Just a word of caution - you might want to check with neighbors or with your city/town about what kind of maintenance might get done in this ditch. In some areas the local town road maintenance may cut along the drainage ditches or even redig them if they have silted in. You haven't been here during the growing season, and I assume you would want to avoid the heartbreak of having your garden dug up or mowed down if this type of maintenance does get done in your town. In my area mowing happens every year to every three years, and ditching gets done based on how much silting in has happened and whether it is interfering with water movement.

Thank everyone. I have a lot more choices than I thought.

I was referring to Filipendula rubra. I know it gets big. I was thinking of putting it a bit away from the mailbox. I thought it was so pretty though.

And I don't know if the ditch dries up in the summer. I should probably wait until next year. :-((

nhbabs, I didn't think of that. I'll call the city and ask neighbors.