The purpose of this study was to identify the professional horticultural competencies that vocational horticultural teachers must perform successfully and to distinguish between those competencies needed by entry level teachers and those needed by experienced teachers. A secondary purpose was to examine differences in the ratings of the competencies by the teacher sample with regard to selected educational and personal characteristics. Using 256 professional horticultural competencies selected by a search of the ERIC (Educational Resources Information Center) system and research reports from various universities, a survey instrument was constructed. It was administered to all undergraduate agricultural education majors, beginning and experienced horticulture teachers and administrators, and craft committee members in Pennsylvania. Mean scores for each competency were determined for each group. Competencies considered necessary for beginning and experienced teachers in the categories general horticulture, floriculture/greenhouse management, landscape horticulture/nursery management, turf technology, horticulture mechanics and fruits and vegetables were determined. Personal and educational characteristics of respondents did not significantly influence competency ratings. Recommendations for the incorporation of competencies into various levels of vocational horticulture education were made. (Appended are grand means for each competency, references, and the survey instrument.) (MN)