Slender Vervain A lovely plant for mild areas, Verbena rigida is a bushy, clump-forming, deciduous, tuberous perennial with a neat, low habit and oblong, mid-green leaves. From June to September, clusters of bright purple, typical vervain flowers rise above the foliage, giving a jewel-like effect, particularly lovely with silvery or grey foliage plants. Not for cold areas, but may survive winter in very mild, coastal areas with a deep dry mulch; alternatively, grow it as an annual. Slender vervain holds the RHS Award of Garden Merit. Site: Sheltered, sunny siteSoil: Any moist but well-drained soilPosition: Full sunSeason of interest: June to SeptemberHardiness: Half-hardyHeight: 2’ (60cm) Spread: 16” (40cm)