We sell a wide variety of options and sizes depending on the specific plant you are looking for. Options for the container size are listed on the product page. We offer container sizes that range from being shy of a quart all the way up to extremely large B&B (balled and burlapped) material.
To better understand the container sizes from our smallest containers all the way up to #7 Containers, you can check out this video: https://youtu.be/RdnB5leoRrs.
Generally speaking, the older the plant is, the more developed the root system. The more developed the root system, the larger the container needs to be to house the root system. So the size of many plants is determined by the size of container that it is sold in. The larger the container, the larger the root mass and the more mature the plant, tree or shrub is going to be.
So why not list the actual height of the plant?...
When we can, we will list a specific height or size directly on the product page in the size option. However, different plants grow at different rates and require different pruning/shaping and varied times. Thus, listing a specific size is not always possible. The main goal it go make sure that you are getting the heathiest specimen with the most healthy and well-developed root system possible.