The planting site is located in USDA Zone 4, if you live south of Zone 4 you can expect considerably more growth.
Site preparation should include removing all vegetation and smoothing the area out for a weed barrier. Good site preparation is critical in maximizing the growth of your cuttings. Reducing competition will boost growth dramatically. Competition for moisture and sunlight is the limiting factor in their growth.
The fabric is held down with landscape staples. The staples are wire formed into a U shape. You may make your own from stiff wire if you prefer. Place the staples around the perimeter as well as one at each cutting (and possibly many more). If the wind gets under the ground cover, it will be promptly removed. Make sure you hold it down! Logs, fence posts, rocks, cement blocks, etc. can also be used to help hold it down.
Using a ground cover will make maintaining the planting much simpler. For hybrid willow and hybrid poplar you can use woven fabric or black plastic.
After stapling, it should lay flat against the ground and be relatively tight. You don't want it flapping in the wind and rubbing on the cuttings.
Use a Cutting Planting Bar or similar tool to create a hole through the fabric and into the soil nearly as deep as the cutting is long. You may need to slit the fabric first depending on the tool you use.
Place the cutting in the hole as deep as possible while leaving no more than 1/3 of the cutting above ground. Any exposed buds on the cutting will grow leaves and branches, all buds below grade will grow roots. The staple near the cutting will assist in holding the fabric down and direct water toward the cutting.
After planting the cuttings, the fabric should be tight between all staples. If not, add more staples until it is tight and snug to the ground.
In 1 to 2 weeks depending on conditions, the cuttings will come to life and begin putting on top growth.
At 6 weeks they are approximately 2 feet tall.
At 10 weeks 5' - 7' tall.
At 14 weeks they are really putting on the growth.
At 16 weeks the tallest hybrid poplar is 10′ 1″, tallest hybrid willow is 8′ 3″.
Here is the same screen after 2 full growing seasons.
The trees will require minimal future care beyond the occasional weed to be pulled and adequate moisture (natural or supplemental).
Have any questions? Let us know in the comments!