These are very slow growing plants. Put them in a sunny window. I water mine once a week. It takes a couple of years for them to really start growing. The second year you will start to see leaves. Mine are 3 years old now and are about 8 inches tall. I think this is why the plants aren't cheap.

Thanks for the info. I was beginning to wonder. I knew that they were slow growing but am actually surprised at how fast my big ZZ is growing. It's in a 20" pot and has put out about 10 new leaves since the spring. That plant thrives despite being completely ignored. It's sitting under a skylight and I don't know that it's been watered more than twice so far this year and I've never fed it.
Karyn