Coppelia' is a patent-pending variety so propagation is prohibited. Growers will commonly plant helenium outside during August and September using one 70-cell liner in quart or gallon containers. Remove old stems before overwintering. Dormancy breaks in late spring. Allow plants to develop at natural temperatures for normal growth.
Plants grow taller at warmer temperatures.
Best growth occurs at 50F-55F night temperatures. Avoid overfertilization to prevent tall, soft growth. Watch for botrytis, powdery mildew, vine weevil and slugs, which can be pests during production. Plants have a long blooming period of six weeks. Mature plant habit is 39 inches tall by 18 inches wide.