Churchplanting vs. Start a Nursery

There is much talk and writing about church-planting. I wonder if this term is not misleading. For one thing the church seems to be more then one plant. If we want to make the connection to the plant or gardening world we need to see that a church consists of many plants, more like a nursery. Some of those plants are older, stronger, some have just come out of their seeds. Others are sick and need treatment or special care. There is no plant the same like the others and each plant has different functions and attributes.
Can we really plant a church? Or is it more building a nursery?