Available in 10 colors, the Empress series is uniform in bloom time and habit. Varieties in this series feature large individual flower heads. Empress verbena are bred to tolerate heat as well as mildew and water stress.
Use a rooting medium with a well-aerated soil structure. After sticking, water the cuttings uniformly well for a good soil to stem connection. Temperatures should be maintained at 65-75° F day and night. To enhance and promote uniform root development, apply bottom heat at 72-75° F. Mist for four to six days as needed and until roots begin to push into medium. Excessive misting can result in disease and leaching of nutrients. Maintain light levels at 1,000-2,000 foot-candles during rooting. After cuttings have established roots, increase light levels to 2,500-4,500 foot-candles.
Before transplanting, water rooted cuttings well and moisten finish container medium. Alternate liquid feed of 200- to 300-ppm 15-0-15 and 20-10-20. Leach regularly to maintain an EC of 1.5-2.0. Grow at 65-75° F during the day and 60-65° F at night. Increase light levels to 5,000-6,000 foot-candles. A hard pinch (above the fourth or fifth set of leaves) once plant roots reach the edge of the container will promote basal branching.
B-Nine (daminozide) can be used to reduce plant stretch. Verbena also responds to negative DIF.