Lobelia siphilitica · Campanulaceae

Great Blue Lobelia

✅ Pet-friendlyPerennial plant that maintains foliage year-round.30 to 60 cm

LightPartial shade

WaterFrequent; moist soil.

DifficultyMedium

ColdWithstands light frosts down to minus 5 degrees Celsius.

Partial shadeFrequent; moist soil.MediumWithstands light frosts down to minus 5 degrees Celsius.

Description & origin

The Great Blue Lobelia is a perennial plant known for its vibrant blue flowers. Ideal for moist gardens, it attracts pollinators such as bees and butterflies. It is an excellent choice to add color to shaded areas.

Size

Remains compact, ideal for borders and flower beds.

Foliage

Green lance-shaped foliage that remains year-round.

Flowering

Blooms in summer with tubular blue flowers.

Detailed care

Light

Prefers partial shade locations but tolerates some direct sunlight.

Soil

Needs rich, organic matter soil that is well-drained.

Watering

Requires frequent watering to keep the soil moist, especially during dry periods.

Temperature

Tolerates low temperatures but prefers temperate climates.

Fertilising

Fertilize monthly during spring and summer with a balanced fertilizer.

Repotting

Transplant in spring when necessary, ensuring enough space for growth.

Pruning

Remove wilted flowers to encourage new blooms.

Propagation

Propagates by seeds or division of clumps in spring.

Common problems

Root rot

Occurs in poorly drained or overwatered soils.

Powdery mildew

Fungus that appears in high humidity conditions.

Slugs and snails

Can damage leaves and flowers.

Uses & curiosities

In the garden

Attracts pollinators
Ideal for borders
Adds color to shaded areas

Other uses

Used in rain gardens and pond edges.

Did you know…

The name 'siphilitica' comes from the historical use of the plant in treating syphilis by Native Americans.