Verbena litoralis aka Brazilian Vervain

Verbena litoralis is in the verbena family, Verbenaceae. Its home range runs from Mexico into tropical South America. It grows where the climate has a clear dry season. In the wild, it grows in meadows and thickets. It also grows on rocky slopes and in fields. Some sites lie in pine-oak forests. Records span heights of 279–9,843 feet [85–3,000 metres] above sea level. These sites have both wet and dry ground.

This plant can live as an annual or short-lived perennial. Its stems stand upright or rise from a slanting base. Plants may have few branches or grow many of them. The lower stems can turn woody as they age. Useful Tropical Plants lists a height of 3.3 feet [1 metre]. Its fuller account gives 1–6.6 feet [0.3–2 metres]. Plants in good soil can outgrow those in poor sites. Bees and other insects carry pollen between the flowers. The supplied species account gives few details about leaves or fruit.

In gardens, it prefers full sun and dry ground. It can survive long spells with no rain. In reported climates, rainfall totals 100–800 millimetres each year. The dry season may last up to ten months. Snow does not suit this species. In dry climates, it may withstand brief cold spells near −5°C. This does not show which hardiness zone suits it. The account lists seed as the way to grow new plants.

People gather wild plants for use in local medicine. Gardeners in Ecuador also grow it for that purpose. Reported remedies treat fever, influenza, and smallpox. These are records of folk use, not proof the treatments work. One method calls for crushing the plant, then boiling it in water. The drink is said to taste bitter and act as a purgative. This means it makes the bowels move. Useful Tropical Plants records no use of it as food. That source lists no known hazards. This does not prove that the plant is safe.

Its spread is a key concern when planting it. It has become invasive in tropical and subtropical regions. Reports say it crowds out pasture plants and native plants. Forests that people have disturbed are among the sites of concern. Elsewhere, it stays mostly beside roads, streams, and tracks. It also grows on waste ground. The source notes gaps in proof of wider harm to nature. Those gaps do not remove its known weed risk. That risk still calls for care.