Plant size is a consideration in the cost of installing a landscape design. Using smaller plants reduces the cost, but you must wait for the plants to mature. Larger plants cost more because someone has been tending them for more years. It is wise to use larger plants where you need instant impact and smaller ones where you can enjoy the transformation of your landscape over a couple of seasons.
In this landscape we chose to use smaller plants and spend the budget on hardscape elements, but in two weeks, some of the plants have already doubled in size while others will need a season or two to reach their full potential.