Verbena urticifolia aka White Vervain

Verbena urticifolia belongs to the verbena family, Verbenaceae. It is a perennial, so it lives for years. People call it white vervain or nettle-leaved vervain. It grows wild from Canada through the central and eastern United States. It is not native to Britain or Ireland. It grows in woods, pastures, and along stream banks. It also grows by roads and on disturbed ground. Chicago Botanic Garden places it at shaded woodland edges.

The plant grows upright. Chicago Botanic Garden gives its height as 3–5 feet [0.9–1.5 metres]. Plants For A Future lists just 1 foot [0.3 metres]. Leaves grow in pairs on opposite sides of the stems. Each leaf is lanceolate, with a broad base and pointed tip. Coarse teeth line its edges, and its surface feels rough. The species name points to leaves that look like nettles.

Small white flowers open a few at a time. Each has five petals. Thin, drooping spikes form large panicles, or branched groups, at stem tips. More spikes grow from upper leaf axils, where leaves meet stems. One plant can bear hundreds of these thin spikes. Chicago's account gives July and August as the bloom months. Its bloom list runs through October. Native bees take pollen from the flowers. Plants For A Future lists flies, moths, and butterflies as pollinators too. Each flower has both male and female parts. Plants are self-fertile: they can set seed with their own pollen. Birds eat the seeds as they migrate in fall.

Grow white vervain in moist soil that drains well. Plants For A Future lists sand, loam, and clay as suited soils. It gives a range from mildly acid to mildly alkaline soil. The sources differ on light needs. That source calls for sun and rules out shade. Chicago Botanic Garden lists part shade instead. Give moderate amounts of water to keep the soil moist. Chicago lists USDA zones 3–9. Plants For A Future gives hardiness near 5°F [−15°C]. Suggested sites include beds, borders, and sunny woodland edges. Its pollen and seeds help wildlife. Chicago also notes that it resists deer.

Plants For A Future warns it may act as a weed. It lists no known uses as food or known hazards. This does not prove it is safe for people or pets. It notes past use of roots as remedies, not proven treatments. It describes growing seed under cover in early spring. Other ways to grow more plants include spring division. Basal cuttings, taken from the base, are an early summer option. Small divisions can grow under cover before planting out.