Protea L. sp. can be assigned to groups according to similar times of flower initiation and harvest. The stages occurring during flower initiation and their synchrony relative to shoot growth were investigated for three cultivars when flower initiation occurred on the spring growth flush. For all three cultivars, the spring flush was preformed and enclosed in the apical bud before spring budbreak. During elongation of the spring flush, the apical meristem produced floral primordia which differentiated into involucral bracts. After completion of the spring flush, meristematic activity continued and produced floral bracts with florets in their axils. The different cultivars were characterized by differences or similarities in the time of budbreak, and the rates of shoot growth, appendage formation, and flower development. Insight into the time of flower initiation relative to vegetative growth could be useful in making management decisions, as well as forming a basis for manipulation of the flowering process.

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The date of pruning affected flowering time of Protea cv. Sylvia (P. eximia × P. susannae) by influencing the flush on which inflorescence initiation occurred, and the harvest could be manipulated to fall within the optimum marketing period for export to Europe. Flowers initiated on the spring flush reached anthesis in January-February, those on the first and second summer flushes in April-May and July-August, respectively, and those on the autumn flush in November-December. Thus, flowering shoots harvested within the optimum marketing period (September to February) initiated inflorescences on the autumn and spring flushes. Because shoots on the spring flush initiated inflorescences readily, many flowering shoots harvested in January and February (following initiation the previous spring) were short and therefore unmarketable. For commercial production, pruning in July is recommended to allow harvest in October-December of the following year. Since the vegetative and reproductive cycles necessary to produce inflorescences on long stems span more than a year, a biennial cropping system is recommended.

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