Verbena can be trimmed by cutting back the branches that have bloomed to a node or joint - you don't have to cut back all the way to the main stem, just to the nearest branching point. You can also just take a shortcut and shear the entire plant back by one third then fertilize and water well for a flush of new growth. Even if you never prune back your hanging basket it should continue to bloom all summer by making new growth as soon as the flowers fade. Verbena is susceptible to white fly so don't let your hanging basket get stressed by lack of water or fertilizer. This plant loves full sun and can tolerate summer heat. Enjoy and Keep Growing, Marianne Binetti