Spring Sunday Afternoon in San Antonio

Prairie Verbena, Indian Mustard and Blue Bonnets in bloom along the walking trail at the UT Health Science Center.

Prairie verbena [Glandularia bipinnatifida] is a common wildflower native from the Mississippi River west to Arizona and from southern Mexico north to South Dakota (Umber, 1979). Correll and Johnston (1970) reported Verbena bipinnatifida Nutt., the previous scientific classification for prairie verbena, often covers large acreages in dry plains, prairies, pastures, and disturbed roadsides. These large populations are associated frequently with gypsum, limestone, or calcareous soils (Umber, 1979). Prairie verbena has a variable growth habit. Plants of a similar age from the same population may be either prostrate or erect (Umber, 1979). Habit variability may also be related to growing conditions and season. In early spring during short days, the internodes are reduced and the plants are more prostrate. As day length increases, internode length increases and the plants attain a more upright habit. Prairie verbena has densely branched stems covered with stiff white hairs (Correll and Johnston, 1970), leaves that are deeply incised, and several growth forms or ecotypes resulting in some attaining specific or varietal status.

The yellow flowers of the Indian Mustard (or India mustard) are a pretty contrast to the blue of the Prairie Verbena.  All mustards considered wildflowers were introduced to North America from Eurasia and are members of the Brassica family.  Interestingly, six of our common vegetables--cabbage, cauliflower, kohlrabi, Brussels sprouts, broccoli, and kale--were all bred from a single species of mustard, Brassica oleracea.