Henry Lawrence

Main use people are using them for is Windbreaks and Screens, also with that they can help with noise mitigation. It can be used for erosion control, and has been used in buffer strips effectively. In wet spots, can help to suck up the moisture fast, since it is growing so fast. As field breaks, they help wind erosion. It is used frequently as a quick shade tree, plant a couple close together and sling up a hammock. Along hog and cattle confinements, it is used as a visual barrier and offers some odor mitigation. It also is used for phytoremediation. Growing super fast creates a lot of oxygen and creates a carbon sink. Some people are using them in a system to feed livestock the leaves. Possibility I've thought about is using them as living posts. Compared to highly flammable pines for windbreak or screening, using these also can create a firebreak. Hunters are planting them for quick wildlife habitat. They also can plant them together and weave them together to create a living hunting blind. So they also could be created in that same manner into a living fence weaved together. Also I imagine baskets and other crafts it has some use when young. It can be used for firewood, mulch, lumber, pulp, and as a biomass crop.

Summer is the worst time to do the cuttings, so if you had bad success rate that would be why.
When they are dormant, then yes, they could be sitting around for few months and still possibly viable, but I don't see that happening in july and august, they desiccate too fast.
Easy to tell by just using fingernail on bark to see if green or not. They are the fastest growing willow with a blizzard of uses.
In a lot of situations, its best to keep them with one dominant trunk, since they break apart more readily with multiple trunks and shorter lifespan.
They've been in this country only 25 years, so Jay has one of the 'old' ones. I've seen some that old, and are as big as 100 year old oaks in my area.