Trees and shrubs that look properly spaced when you plant them will crowd each other and compete for water, sun, and nutrients in a few years. If you’re lucky, you can transplant some bushes; if you’re not, you’ll have to throw away starved shrubs.
Try this instead: Before digging, read spacing instructions. Give trees plenty of space—you can always fill in later. Stagger bushes and plants and create two rows, which will create more breathing room. The results will look absurdly sparse at first. But live with it. In a few years, your shrubs will fill empty spaces without suffocating each other.