There are two kinds of native verbena growing all around Austin, one of which is the tall, spindly plant called Texas vervain, or slender vervain (Verbena halei). This verbena has small light purple flowers that start forming along the stem and gradually move up the lengthening stem as the plant grows. It is a very easy plant to grow and we them in various gardens. Texas vervain grows to about two feet tall and by the end of summer can look pretty straggly as the lower leaves die and the long stems with seeds are flopping over in all directions. The flowering stems get to be over six inches long, with just a small bunch of blossoms at any given time. Although well adapted to the heat and drought, the individual plants rarely live more than a couple years and die during their second or third winter. They reseed freely, though, so we are never without a few of these plants. Texas vervain is known to have medicinal properties.

The other commonly seen verbena is the Dakota vervain (Verbena bipinnatefida), which has dark purple flowers and has a low, trailing habit. It forms brilliant mounds of purple with lacy dark green foliage along roads and sidewalks. I've tried growing it but it doesn't survive in our gardens, probably because we can't provide the full sun exposure it requires.
Our most recently acquired vervain species is sandpaper verbena (Verbena rigida or V. venosa). This plant is native to South America and is also called tuberous vervain and veined verbena. It has naturalized in this area and grows in abandoned fields and empty lots. The blossoms are tiny but thickly clustered and are a brilliant purple. The narrow leaves and long stems are stiff and covered with bristly hair, hence its common name of sandpaper. The other two common names also refer to physical characteristics of this plant: the blossoms have a pronounced stripe down the middle of each petal (veined), and the plant grows from sturdy underground roots and spreads aggressively (tuberous). It handles drought well and even blooms in partial shade. Possessing qualities that could make it a troublesome weed, sandpaper verbena is easy to grow and one of my favorite garden plants.