All are grown for their tubular, lipped flowers, which resemble those of honeysuckle (Lonicera) or Salvia. Annual kinds are low plants for edgings or hanging baskets; perennial sorts are larger, vertical-growing plants with flowering stalks that rise above the foliage.Lobelia erinus
From South Africa. Popular, dependable edging plant 3 to 6 in. high. Compact forms reach 5–9 in. wide; trailing types spread to 1 1/2 ft. Leafy, branching stems with green or bronzy green foliage. Blooms from early summer to frost, bearing 3/4-in.-wide flowers in light blue to violet (sometimes pink, reddish purple, or white) with white or yellowish throats. Lives over winter in mild climates. In mild-winter, hot-summer regions, grow it as a winter-to-spring annual.