The final, most drastic cutback will be in the fall when plants are cutback so winter annuals such as pansies, dianthus or bluebonnets can the interplanted among the Verbena. The third problem with Verbena is that they are susceptible to a few pests. I mentioned that Verbena is susceptible to the fungus powdery mildew if planted in a wet, shady locale. Organic growers can use insecticidal soaps or sulfur dust but an invasion of spider mites MUST be dealt with or plants can be destroyed. Leaf miners which make little trails in the leaves do not cause significant damage but are ever-present.
Thrips can also be a problem and can be controlled with the same insecticides.
It is a rapidly spreading perennial Verbena with showy lavender-blue flowers. This variety was discovered in England by Greg Grant, former Bexar County Extension Horticulturist, while on a plant collecting trip to England for Lone Star Growers. Lone Star has graciously made this new, blue verbena available to everyone to try this year. This area of Texas will be the test site and we would appreciate your comments after growing this tough little beauty from the Old Country. Regardless of its heritage, 'Texas Rose' is another verbena worth trying.