This number refers to the container size of a plant. We can ship #1 through #5 size plants via UPS. If you live in the Southern California area we have larger sizes available for delivery or pickup at the nursery. See photo below for an example of container sizes. Plant size varies depending on season, type of plant and other factors, and may not be represented accurately by the following photo. Size represents the container size and not necessarily the height of the plant you will receive.