His first one evolved gradually, as he discovered, through working in it, how he wanted it to be, so this time, he knows in advance what he wants and where. So, where do the damsons come in? Well, in that garden, there is a damson tree, heavy with damsons at this time of year, and as there are no jam makers in the immediate vicinity, a lot of them end up on the ground.
Are you beginning to see where this is going? In a typical male fashion - i.e. if it's not in front of my face, I don't see it - he spent a week coming home after working on the van and shedding flattened damsons across the living room floor from the soles of his shoes with gay abandon.