Custom Duty and plants import permit

I live in NJ, USA and I am interested in purchasing some plants from china. Do I need to pay the custom duty? (Those plants are not for commercial usage at all. I am planning to fill out my backyard.)

Also anyone familiar with theis import permit form? Do I list all individual plants or just by genus. ie, can I just list Epimedium under the plant or I need to list all different species?

Thanks.

Fang