Here at Stonewell Farm, we have an abundance of water. Whenever we get a heavy or persistant downpour, spring water flows from the ground throughout the property. In 2013 we ordered a selection of willow cuttings from the USDA and planted them at the bottom of a slope where except for the height of summer, surface water is always present.
We coppice the trees every two or three years, which produces a thicket of new stems.
These stems are 10 to 12 feet tall, but still pliable for the required purpose.
Willows produce indolebutyric acid and salicylic acid, two hormones which help to stimulate root growth
Providing the planting site is consistently moist - the pond is directly behind from where I took the photo - and the ground is sufficiently yielding, the cuttings can simply be pushed into the soil. I used a crowbar driven in at an angle, to a depth of eight inches.
one, perhaps two years growth should suffice to complete the dome.