Summary In order to test the nutrient diversion hypothesis in the woody shrub Boronia, plants were fed 14CO2 every 10 days during the first 70 days of flower-promoting conditions. Basal and apical tissues were harvested from the fed lateral 24 h after labelling. The samples were partitioned first to remove chloroform soluble material. Amino acids, organic acids and phosphates, and sugars were extracted into alcohol, while proteins, starch, and structural material remained insoluble. On a lateral of Boronia the first flower buds normally initiate approximately three to four nodes below the apex. This is associated with the cessation of leaf expansion in the subtending leaf. Prior to flower bud initiation it was found that there was an increase in the sink strength of the subtending leaf. This could be seen by the ratio of dpm in apical tissue compared with the basal tissue. In addition there was an increase in the percentage of 14C partitioned into the sugar, amino acid, and protein fractions in both basal and apical tissue.