Roseleaf raspberry (Rubus rosifolius Sm.), a thorny weed in the highlands of Quezon province, Philippines, has shown potential in the food industry. Analysis of the phytochemical content of its fruit revealed promising medicinal properties. However, attempts to produce fruits at low elevation have failed, while the specific influence of agrometeorological conditions in lower altitudes is yet to be studied. We investigated the phenological characteristics of roseleaf raspberry plants at different elevations: in their native setting at 774 m above sea level (masl) and at low elevation (31 masl). Plants started producing flowers at the end of October and became more profuse in the later months. An observed critical feature of individual roseleaf raspberry flowers across elevations was poor overlap of anther dehiscence and stigma receptivity. Fruit set failure and flower abortion were abnormalities found to cause low fruit production as well as poor fruit quality among plants at low elevation. Excessive heat accumulation in flowers and insufficient carbohydrate supply in the shoot apices are possible causes of these abnormalities.