Hi, 

These actually appear to be Lantana, not Verbena; they are related, but not the same plant.

The purple "blooms" are berries. They are formed from the developed from blooms that were pollinated while the plant was still outside, presumably. It is highly unlikely that they would have been pollinated indoors.

Lantana berries can be toxic if consumed at the wrong ripening stage, so don't let anything eat them, children or pets if you have either.  (it's safe to just clip them off though).

Neither Verbena nor Lantana are considered houseplants or typically overwintered indoors, especially since they are sometimes prone to pests like whitefly; usually, gardeners just let them die with frost and replant after the last spring frost. So in Maryland they are kept as summer annuals.

They are however, tender perennials, so overwintering indoors might let them survive until May when they can go back outside. They are sun-loving plants though, and no indoor light is going to be bright enough (and the days are too short also) during winter for them to thrive and keep blooming; the goal of overwintering inside is just to keep them from freezing, not really for any growth or development. Some people will do this with annual geraniums, begonias etc. They tend to not look full and healthy during the winter, but if you keep them minimally watered and they don't develop any pests or diseases, they will probably perk up in the bright late spring sun when the days are longer and the danger of frost has passed.  

 We would recommend to stop applying biofungicide as they are not showing signs of an infection and a pest or disease issue should be identified before any treatment is used. Should you identify a pest or disease we encourage you to look at the label and make sure it states for inside use, even if it is organic, it could be harmful if not meant for indoors. 

Let us know if you have further questions. 

Emily