I have a spot which sounds very similar to yours, without the woods behind. The mower marks, poor grass growing, weeds, puddles of water, & the consistent wetness are/were exactly the same. In my case it was a man-made depression to handle run-off from 6 houses in my subdivision to a large drain located in the corner of my back yard. There is a 2nd drain just outside my property by a few inches on the other side for the houses on that side to drain into. My yard is quite sloped side to side and front to back with a bit of extra dropoff just before the drain area. There was no possibility of raising the elevation or using the lasagna method. Here's what we did. We left the lowest part alone, except for digging out a bit here and there to direct the flow a bit. We added some gravel, some 2 inch egg rock, and a few semi-big rocks to make it more attractive, making a sort of dry creek, which isn't all that dry. This rock/gravel area also serves as a pathway through the area when it's dry enough. We added a couple of smaller sideways gravel paths so we can get in and work in the area as well. These don't actually handle water, but they look like they could & we tried to keep them as natural looking as possible by meandering the paths a bit and putting rocks at strategic points. We also have a few areas where we use large flat rocks for crossing. Any green stuff that intrudes into this area is cleared out by using Round-up once or twice a year. This area is a really small portion of the whole & we tried to keep it as small as possible (narrow paths etc.) & quite simple (Round-up) because rock hauling & weed removal from rocks is for people much younger than us! In the rest of the area we used a modified lasagna method. We used newspapers (6-8 pages dampened) and put down over it a small layer of dirt, mixed with bagged Humus and Manure, and covered it with a 2 inch layer of mulch, trying hard not to raise the elevation more than a little bit & start a war with our neighbors (all at a slightly higher elevation than us & them wanting to keep it like that). We did the work in the fall and let it go for the season. It looked neat and needed no more mowing, with only a moderate leaf cleanup off the rocks (pushed onto the mulched areas). Over the winter I developed a plan to add shrubs to the area, checking books & catalogs for things that can tolerate both wet and clay. I decided to plant only small bareroot shrubs, 12, 18, 24 inches tall, because I had no faith in anything actually being able to live in this spot. I settled on Variegated Red Twig dogwood which I bought locally as small shrubs & Itea, Clethra, a cutleaf Sambucus, & Buttonbush (Cephalanthus occidentalis) that I bought as whips through a catalog. In addition, I purchased a couple of Emerald Arborvitae shrubs locally for some Evergreen color near the back center of the garden on higher ground. I also bought inexpensive (no cultivar name) starts of things like Ostrich Fern, water Iris, & Cardinal flower from a catalog and added a few plants from the pond section of the local nursery, plus moved a few astilbes (that I didn't like the color of) from another part of the garden. To my surprise most everything took quite well. Since that time (more than 5 years ago) I have tried different shrubs and perennials, pulled out a lot of things that got too big too fast, & had a great deal of fun with my "wet" garden. I have no idea if it would ever have qualified as a bog or a fen - but it was certainly wet enough. I have found that a lot of things will grow in the area and on the edges of the area. It never has to be mowed, there aren't any mower ruts anymore, it doesn't need watering, there isn't even much standing water anymore, and it's quite lovely. BTW, local landscapers, 5 of them, had been brought in to look at the yard during the summer before we did this work - none would give us an estimate (no way to get heavy equipment into the yard) and only wanted to plant River Birches or Bald Cypress trees in the corners. They said nothing else would work. A wee bit big for my small suburban lot & wouldn't my neighbors have loved the tree branches spreading all over their yards! I'm glad we did it ourselves. There are really just so many things that love this area. Here's a few: You can't tell from the picture but behind the Lady's Mantles (themselves 2 ft tall) is a dropoff and a big drain right in front of the yellow zinnias, which are further away than they look in the picture. To the left on the top ridge of the bed is Miscanthus sinensis Strictus and to the left Hibiscus moscheutos Sweet Caroline, both huge tall plants, blocking the view into the "wet" garden, except for this peek. Behind them are various water/damp loving perennials & some small shrubs, with a mixed row of damp & clay tolerant shrubs behind them along the fence. Here's the rest of the Strictus grass and Lysimachia Alexander. The entry path to the "wet" garden is just on the left of Alexander. On the left side of this narrow path is a dwarf Meadowsweet, about the same size as Alexander on its own little island. There is another path to the left of it going the other direction to higher ground. You can also see a bit of the Ostrich fern which is actually about 5 ft back and on the far edge of the drainage ditch. Trollius, an early bloomer likes damp. The dark shrubs in the background are Physocarpus Diablo on the higher back ridge, not quite filled out yet this early in spring. Bowles Golden Sedge looks great against the Diablo foliage. Japanese Primrose (Crimson Strain) sprinkled here and there in the area. Love the color. Virginia Bluebells, one of my favorite spring ephemerals. This runs along the fence side of the bed, before the Swamp Hibiscus is even out of the ground.

Every now and then I take a look at this forum and I think people confuse wetland or moist woodland gardens with what a bog is. Of course some people would call a bog a swamp and that is wrong. Bogs have specific plants and trees that grow in them. They are filled in ponds or on the edge of lakes. Bogs can have slow moving streams flowing through them. A great deal of true bogs are seep bogs. The seepage comes from a fresh water spring on the edge of a hill or coming up from the earth. This is Websters wording of a bog: wet spongy ground; especially : a poorly drained usually acid area rich in accumulated plant material, frequently surrounding a body of open water, and having a characteristic flora (as of sedges, heaths, and sphagnum)[end] I think it was a bad choice of words using "rich" in accumulated plant material. It gives one the impression that the earth is rich and good for plants of many kinds. But in the same sentance Websters used the word "acidic". There are alkaline limestone bogs. Michigan is a state where many akaline bogs can be found. In a typical bog that is acidic the pH is between 3.5 - 5.5, thats a bog. In a akaline bog the opposite, pH 7.2 > thus unique plants grow in the bog set up for the land or wetland they grow in. Bogs are not shaded areas, though with time hardwoods move in an the bog habitat in nature changes with shade killing the bog plants out. Most bog plants are sun lovers, they are not shade growing plants. The skunk cabbage could be found on the upper borders in the shade as the hardwoods slowly move in toward the wet center of the bog. Another plant you could use with the skunk cabbage if filtered light is the Jack-in-the-pulpit. As well skunk cabbage can adopt to sun conditions, it isn't a plant I would use in the bog itself other than a border plant due to the size of the leaves shading out the plants that should be in the bog. Think Cranberries in NJ or MA, blue berries line the bogs in the mid-Atlantic and northeast. Rhododendron's or Azalea often occur above the real wet area as they enjoy acidic soils.In Florida the acidic bogs may have blueberries and unique Azalea along with a plethora of other acidic shrubs. Trees common to bogs are Pine, many types. In the south the long leaf or slash pine. In some areas pond pine. You will not find pitch pine. In the north you have spruce and other evergreen trees along with a couple pine species. All over you may have cedar trees growing slowly in the bog. You may find the Bald Cypress tree in southern bogs, however they are not a bog tree. Often they invade into the wetlands and are suitable. The pond cypress is a more proper bog tree along with lobbolly Bay, or sweet bay. Sphagnum moss species are the common ground cover, very thick and many carnivorous and other very acidic plants cover the grond. Hat pins, bog buttons, various orchids, but not Hosta or canna lillies. They are not bog plants. However why I have briefly described some true bog traits anyone is allowed to call things whatever they want. I for instance have started calling cars, tractors. While both are motorized vehicles like the marsh or moistwood to the bog. Take Care, Mike

Technically bogs have an acid pH, so what you have is a different type of wetland, a marsh, even though it is commonly referred to as "boggy". This would not matter except that true bog plants like pitcher plant (Sarracenia) and cranberry (Vaccinium) need acid (low pH) to grow well. You will want to look up suggestions of plants you get here (including mine since my soil is more acid than yours) since some plants require a certain pH and some are quite flexible. As others have suggested, watch that you don't plant invasives since you have a stream that flows through which would carry seeds. (Iris pseudoacorus is on the invasive list in many states.) Some suggestions of east coast natives that are happy in wet soils: Shrubs: Winterberry holly (Ilex vertcillata) is not evergreen and has bright red berries in fall and winter. Need at least one male for several females. Clethra has late summer pink or white flowers and nice yellow fall foliage Swamp rose (Rosa palustris) has single pink flowers in early summer Pussy willow, some of which are native and some of which aren't, but are not usually on the invasive list, I don't think. Button bush has white round balls of flowers (think Sputnik) that the butterflies like in summer Red-twigged dogwood has selections with variegated foliage or plain green, and bright red winter twigs as long as the old wood is cut out every couple of years. Herbaceous plants: Clematis virginiana won't grow in standing water during the growing season, but is a native white-flowered clematis that grows on our stream floodplain where it is occasionally flooded for short periods and never gets really dry, and so might work well near the edge of your wetland. It will grow well up into shrubs or trees with low branches, so I would plant it just outside of the 10 year width of one of your large shrubs. It has summer flowers and pretty fuzzy white seed heads. Irises such as blue flag and Louisiana are good suggestions as is Cardinal flower, Lobelia cardinalis. Another Lobelia that will do well in damp areas ( though not in standing water like cardinal flower) is great blue lobelia, Lobelia siphilatica. Marsh marigold is a very early bright yellow bloomer (with the daffodils around here) that will be happy in slow moving water a couple inches deep or even average garden soil, though the plant will go dormant in dry summers. In general, since you will view this area from a bit of a distance I would plan on planting most of these plants in groups. Many can be started from seeds or cuttings once you have one plant. You may need to dig or cut back cattails until other plants are able to get large enough to compete.

I think that Kwoods is pointing out that it seems difficult to convince the OP one way or the other on the depth. This is a huge project to tackle if you don't have any previous experience. I think that njb had a good idea to start with plants in a kiddy pool. If I were going to do this I know I would want to know everything I could before I started. I went through all kinds of angst when I was building my little bog. I can't imagine what it would be like if I were trying to build a complicated pond and marsh that required $700 worth of liner and the removal of 40 tons of soil. I'd probably ask local professional pond builders for opinions. Yikes.