Vegetative and fruit responses of ‘Montmorency’ sour cherries to Alar were evaluated from 1966 to 1968. Mature trees were treated with from 1000 to 8000 ppm of Alar at 2 weeks after full bloom. Alar significantly increased fruit color and decreased the force required to separate the fruit from its pedicel early in the harvest season. These differences were sufficient to advance the start of commercial harvesting one week. Fruit firmness was significantly increased in both handpicked and mechanically harvested fruit. Alar treated fruit showed a significant ability to resist softening when mechanically harvested. Fruit color and firmness enhancement was evident in both canned and frozen processed fruit. Alar altered the fruit growth curve and contributed to a more uniform size. Fruit acidity and respiration were significantly reduced. Alar reduced terminal growth, by reducing internode length, but increased flower bud initiation.