When working with Plantings, the default level-based family is great for plants that are on the ground. But what about Plantings in pots or planters?
There are a variety of ways that you can get a Planting family hosted on top of a planter or pot, but one of the easiest methods is to turn on Work Plane-Based in the Family Parameters.
In the Family Editor, click on Family Category and Parameters, and check Work Place-Based.
Then, when placing the Planting, select Place on Face in the Modify Ribbon.
If you have the same plant on the ground (hosted to Topo) and also in a planter, I would recommend having two separate Planting families: one that is Work Plane-Base and one that is not.
You can switch back and forth between Work Plane-Base and not, and nothing will happen to your existing plants. However, if you try to copy a plant that was placed on Topo, but the Planting has been modified to now be Work-Plane Based, you will get the following error:
You will get a similar error if you try to copy a plant that was placed on a Face, but the Planting has been modified to not be Work Plane-Based anymore.
So if you need to place Plantings in a pot or planter, make a new Work Plane-Based family.