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Prune one-fourth of the plants top growth, include old flower blooms. Take care not to prune on the main stem. The next bloom will appear in 15 to 20 days. This practice will produce more blooms and wider plants. Cut a stem just below the node, or thickened place on a stem. Plant them in soil and keep them moist and shaded until they take root. Keep them in a container with as much sun as possible until you are ready to plant them in your beds. They will die with exposure to frost. Don’t overtrim them or they may not remain hardy.

Summary:
Deadhead verbena plants after the first full bloom. Prune two to three times per season. Consider using cuttings to multiply your verbena stock, if you want to grow them again. Trim back the plant slightly in the fall if you live in a warmer locale and want to treat them as perennials.