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Great Blue Lobelia

Lobelia siphilitica

Dense spikes of vivid blue two-lipped flowers carry the late-summer shade garden long after most perennials have finished, worked constantly by bumblebees. Happiest in reliably moist ground beside cardinal flower, whose scarlet makes the classic pairing. Short-lived as an individual but self-sows where the soil stays damp. The plant contains lobeline and is potentially poisonous if eaten.

Family

Campanulaceae

Type

wildflower

Lifespan

perennial

Height

2–3 ft

Spacing

1–1.5 ft apart

Light

sun, part shade, shade

Soil moisture

moist

Soil pH

acidic, neutral, alkaline

Bloom

July, August, September, October

Bloom colors

blue, purple

Wildlife value

songbirds

Landscape uses

border, naturalizing, rain garden

Native states

AL, AR, CO, CT, DC, DE, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NY, OH, OK, PA, SC, SD, TN, TX, VA, VT, WI, WV, WY