The big picture is too overwhelming for him

I started the spring project of landscaping a berm that is 200 sq ft.  It had been left uncared for for years..... overgrown and mixing the grass around it with the crown vetch.  I was making a perimeter and shoveling a foot into the margin to start this project.  H wants to help.  So he is kneeling down and picking out tiny pieces of dead sticks from the ground between the leaves.  I commented about what I was doing and what I hoped to accomplish and that my back will start to hurt soon.  I asked if he would do some of the heavy shoveling for a while.  That was half an hour ago.  He is still working on his 2" pile of tiny stubs (that I will eventually be digging up and tossing altogether).  He can't see the big picture of a landscaped berm.  He only sees the tiny sticks.  I think this used to frustrate me.  Before I knew about ADD/ADHD I was thinking he was stubborn and trying to get away with just doing what pleases him without working together with me.  Now I understand. He is tacitly focused on the sticks and no words from me will get him to be able to see the big picture or the scope of the project.  It is useless to involve him.  I will do the project another day and try to not get into a fight with him.  It is still frustrating but at least I wil not put my energy fruitlessly into working together