Answer: Verbena grows and looks best in hot weather. To thrive, it needs good air circulation and well-drained soil, especially in winter. I suspect your plants were performing at their peak during summer and are slowing down until warm weather returns. If the plants are overcrowded they may have developed a fungal disease (they're especially prone to powdery mildew). Look for a whitish film on the leaves. A good garden fungicide will protect healthy leaves; infected leaves will eventually die. You can cut away the brown, wilted debris to remove disease pathogens and open your plants up to better air circulation. When weather warms up your plants should put out new growth.
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