One such project is my rain garden bog garden supplied by the East corner downspout of the main roof rain gutter. The location is shaded in the morning while the sun rises behind neighboring houses and trees, so mid-morning sun until the house shadow casts shade around 1pm through sunset. A little more during the summer since the sun rises earlier and further north of east, crosses a gap in houses and trees, and then climbs higher in the sky enough to clear the treetops earlier.
Last year, I think all I did was clear the winter dead, then the self seeded jewelweed volunteers took over completely.
Taller growing things like milkweeds and cardinal flowers grew on their own, as did the shrubs... And the jewelweed popped and scattered their seeds to their hearts content in fall. 
This year, I decided to pay a little more attention, got rid of a 3 years growth of poison ivy which was preventing me from getting in there to really weed, then systematically cleared the solid growths of jewelweed volunteers away from desirable plants. (I put them all back down on the ground as mulch.)
I discovered a lot of self seeded cardinal flowers and to my surprise, I doesn't look like any plant got completely overwhelmed.
This arum was starting to bloom under all that jewelweed:
Across a path of randomly placed brick step stones the soil is still wet but not so boggy and there is somewhat greater sun exposure. And here I have a wildflower bed of golden Alexander, swamp milkweed that volunteered, monarda didyma Jacob Klein (scarlet red), and more common milkweed. I'm working on expanding the varieties in that bed and also, this spring, expanded the bed itself all the way to the fence border where it is more dry and shady, linking it to the Native Shade Garden.
There is a clump of flowers growing near the milkweed that I don't know the ID for. I think it *might* be hummingbird ipomopsis, but that is a South American native. This one comes back every year on its own and appears to be a perennial. I'll take pictures when it blooms and ask for help in ID.
