Horticulturists oversee landscaping activities and design attractive grounds through their expert selection and placement of plants. The interviewers thus might ask you about plants you'd place in different kinds of light, plants you'd place together or not and how you'd select plants to beautify the environment. You might be in charge of directing projects for repair or improvement of an area, and your prospective employers might check your knowledge of coordinating labor, equipment and materials. Also, be ready to answer questions about laws and standards that pertain to your assigned areas, especially if you're vying for a job with a state or federal agency or for a large project.