This curriculum guide contains five units with relevant problem areas for horticulture. These problem areas have been selected as suggested areas of study to be included in a core curriculum for secondary students enrolled in an agricultural education program. Each problem area includes some or all of the following components: related problem areas, prerequisite problem areas, occupational tasks addressed, learning assessment plan sheets, instructor's guide, information sheets, student worksheets or assignment sheets and keys, demonstrations, transparency masters, and a discussion guide for transparencies. Suggestions are made for use of the core materials, including specific suggestions for using the different components of a problem area. The five units are as follows: (1) horticultural business operation and management; (2) horticultural science and production; (3) horticultural mechanics; (4) landscaping; and (5) floral design. (NLA)