Grow in average, medium moisture, well-drained soil in full sun. Becomes weedy and sparse with diminished flowering performance if not grown in full sun. Does poorly in wet conditions. Removal of spent flower spikes during the growing season will encourage additional bloom. ‘Loch"’ is one of the least winter hardy of the buddlejas, and is only recommended for growing in USDA Zones 6-9. Even if plants do not die to the ground in winter, they usually grow more vigorously, produce superior flowers and maintain a better shape if cut to the ground in late winter each year and grown in the manner of an herbaceous perennial.