Planting cuttings in a swamp

I have some red osier dogwood cuttings coming in the spring. I have read that they like wet areas and i have a swale in our swamp that would be a perfect area to plant them. This area has a hard line that goes from hemlock to wetland grasses.

The cuttings are only 6 inches. Any ideas on how to prep planting sites so these little guys have a chance?
I tried with willow cuttings and had poor results. I cleared a circle and sprayed round up. The problem was I didn't clear a big enough area for each cutting. The swamp growth swallowed them up. The ones that did make it were tubed at planting. Probably 5 of 20 made it in tubes. 0 made it without tubes.
Lay strips of black plastic that's pulled tight and even, then use a probe to poke pilot holes through the plastic and insert the cutting so that 2/3rds of the cutting is below ground.