I get asked all the time about possibilities for sites that are not quite wetlands, but that are saturated in the winter time. Conventional wisdom holds that these places are too wet to grow food, but I know it can be done. Here are some plants that I have heard of and/or seen used on wet sites. Please feel free to add to it, or tell me what your experience has been with them.
Note: This is for sites where earthworks can’t be done for one reason or another, and the site has to be used as-is.
Pacific Crabapple (as a rootstock for other apples)
Willow (basketry, medicine, rooting hormone)
Quince (as rootstock for quince and other fruits)
I have seen people plant in mounds (berms) with some success, though even with plants on them these tend to erode over time. Building hugelbeds in the forest garden seems to wick away excess moisture and improve fertility.
When you reach your lowest point, you are open to the greatest change.
My place has a lot of these conditions! I have a lot of drainage ditches that I clean out into mounds to plant into.
Plum trees have been the best fruit for really wet sites, even with some standing water in the winter they seem to survive. Elderberry are also pretty good there. Hawthorn is also good there and can be used as a rootstock for many pears.
Apples and pears seem to be ok a foot or two up a mound. Any mound will settle over time though so it will need added to if there is not any higher ground within 15 feet to get roots growing into.