I'd be more worried about the standing water than the clay. If the wood chips stay wet all the time I would think some of those seedlings will suffer. If the chips are new you may have a problem with them stunting the seedlings the first year. They tend to suck up all the nitrogen when they first start to break down. They are usually completely broken down by 18 months. There are plenty of people out there growing plants in worse conditions so you should have an easy job of turning this spot into a flowerbed. Some of the plants on your list will be small their first year (Asclepias tuberosa for one); some won't come back after they're done blooming (Bachelor buttons); some should have been planted in the fall in order to sprout in the Spring (the US prairie natives) and some need to be planted in the beginning of Summer (Cuphea). It always works best to start things indoors and then transplant them outside when the weather finally warms up if at all possible. If that isn't gonna happen then you can just toss the seed out there and see what comes up and weed out the weaklings. No matter what you do, it will be prettier than what it looks like now!

Thanks, John! The wood chips/mulch does dry out after a day or two (I will check more carefully). I think the standing water (in the parking lot from running off that bed) was already gone this morning, too. Yeah....most of these are annuals since she only has this year and next year at school, and we wanted more instant results. I hope someone continues at that pound or they are able to reseed, though that mulch may be an issue. Either hear, 1-2 years will be fun if fruitful. I am wintersowing many of them (coreopsis, violas, milkweed, gilia, and balloon flower). Thanks for the advice on the stunting of seedlings. The mulch was put down last summer, I think...is that considered new enough to worry about the nitrogen? Good point....anything will be better than that bare mulch. Lol

Another thing to keep in mind - in nature soil is made up of layers and no matter what the surface looks like there is usually a clay layer somewhere underground. So having clay under everything isn't all that weird. Most annuals don't send roots down much more than a foot so that layer of broken down wood chips will act like garden soil. It may be too rich for some of the prairie stuff, they tend to like sandy or gravely soils. Pansies, Violas or Johnny Jump ups love super rich soil so they will thrive there if the chips have broken down as much as they appear in the photo (it looks fine to me).

If the plat regularly gets runoff from other areas, you may want to mound the soil in the middle and put the flowers there so they don't sit in water. You can put the rocks in the area where water collects. Then as the water slowly drains into the soil the moisture will be available to the plants without drowning them.

Thank you both so much! I was afraid of mass failure. :) Good points on broken wood chips (I feel better now) and thanks for the idea of mounding things/moving rocks. :)