Great Blue Lobelia (Lobelia siphilitica)

Great Blue Lobelia

Lobelia siphilitica

Great Blue Lobelia is a tall, clump-forming perennial that reaches heights of 1 to 4 feet. It prefers moist to wet soils in prairies, woodland edges, and riparian areas. Its vibrant blue, tubular flowers bloom in late summer, attracting bumblebees and other pollinators. This species is an excellent choice for rain gardens and pond edges, adding late-season color and ecological benefits to landscapes.

Characteristics

Product Form	Plant, Seed
Type	Forb
Sun	Full Sun, Partial Sun, Shade
Soil	Clay, Loam, Sand/Gravel, Peat, Calcareous
Moisture	Wet, Aquatic
Average Max Height (inches)	45
Suggested Plant Spacing (inches)	18
Bloom month(s)	July, August, September, October
Bloom Color or Type	Blue, Violet
Dominance	Medium

Range Maps

Sowing Information

Sow seed onto a firm, weed-free seedbed. Hand-broadcast seed making two perpendicular passes for even coverage. If planting a mix, broadcast the grass component first and lightly rake/drag it into the top 1/8–1/4" of soil. Next, broadcast wildflower/forb seed and press it into the soil surface (with a roller/cultipacker or the back of a rake) to ensure good seed-to-soil contact. After seeding, apply a very light layer of clean, seed-free straw (or other weed-free, site-appropriate mulch) to reduce erosion and retain moisture without smothering seedlings. A good rainfall or thorough watering will help settle seed and mulch and improve germination.

Planting Information

Dig a hole in your planting site slightly larger than the plant’s root system. When placing the plant into the hole, ensure that the soil line remains consistent with its original level in the pot. Fill in around the roots with the excavated soil, gently firming it to eliminate air pockets. Water the plant thoroughly the same day to promote successful establishment.