Blue lobelia

Lobelia siphilitica L.

Family: Campanulaceae (bellflower)

  • Bloom Period:
    • Late,
  • Growth Cycle:
    • Perennial,
  • Growth Habit:
    • Forbs/Herbs,
  • Insect Type Attracted:
    • Natural Enemy,
    • Pollinator,
  • Light:
    • Full,
    • Partial,
  • Region:
    • Southern Lower Peninsula,
  • Soil Moisture:
    • Medium,
    • Wet
  • Height:
    • 1-3ft

Natural enemies attracted

Moderately attractive: Orius insidiosus, Chalcidoidea, Cantharidae, Coccinellidae and Plagiognathus politus.

Mildly attractive: Salticidae, Thomisidae, Cynipoidea, Sphecidae, Braconidae, Nabidae and Empididae

Pollinators attracted

Highly attractive: bees including yellow-faced bees, sweat bees, small carpenter bees, and bumble bees.

Pests attracted

Highly attractive: lygus bugs.

Mildly attractive: weevils, leaf beetles, leafhoppers, aphids and thrips

Plant notes

Blue-to-purple flowers bloom in spikes up to 3 ft tall. Plants filled in well in second year of growth, and bloomed throughout August into early September. This species was the tenth most attractive to natural enemies in the late season, with three times as many natural enemies as the grass control.


This plant likes full sun to partial sun, and average to very wet soils. It occurs naturally in wet areas such as ditches, wet meadows and thickets, fens, shores, riverbanks, swamps and floodplains.

Cultivation and management

Blue lobelia can be grown from seed (It flowers in the third year.) or plug material (flowers in the first or second year). This species self-seeds when in ideal locations.