Canola in central Oregon typically grows too tall for hand and wheel line irrigation systems. The objective of this study was to determine the type and timing of growth inhibitors on the physiology of both spring and winter canola under sprinkler and flood irrigated conditions. Two winter and two spring canola cultivars were sown in August 2006 and April 2007 respectively at the Central Oregon Agricultural Research Center at Madras, OR. The growth inhibitors paclobutrazol and ethephon were applied prior to bolting and at the appearance of the first open flower. Heights, maturity dates and yield were recorded and will be presented at this conference. The results should be useful in developing a hybrid canola seed industry in central Oregon.