These Kusudamas are made by folding many units of lily flowers and glueing them all at their base. Not a very complicated process, only time consuming.
The complexity lies in making different types of lilies based of the original unit. Some have longer petals than others, some are broad. The longer petal types require more units to make a ball, while the broader petals requires much less.
The variation on the broader petal types, lends itself to making the Kawasaki Rose Kusudama, which is basically a Kawasaki Rose (specific type of origami fold), inlaid into a green lilly unit. These combined units are them assembled together at the base forming a ball.