Blue Lobelia: Lobelia Siphilitica

Blue Lobelia has striking blue hues and an attractive shape; this perennial plant can elevate the aesthetics of any garden or outdoor space. It is an excellent addition to any landscape design, from attracting pollinators to providing visual appeal.

It is a fantastic choice when you crave flowers that swirl together showy blue blossoms with vibrant greenery in bright spikes. It's a striking, solidly built plant that delights people and pollinators.

The Aesthetics of The Blue Lobelia

Several large flowers spiral around the stout central stem in an extended cluster. They are positioned most heavily along the upper portion of the stem. The tubular flowers have five petals with edges that curl attractively. Two petals form an upper lip—three fuse together to create a lower lip that is more prominent. Blooms are typically about an inch long and may appear solid or striped.

While the bold flowers are the show's stars, the vibrant green foliage shines in its supporting role. The thick, unbranching stem stands firm and tall, allowing the plant to quickly reach two to three feet. Plants reaching four feet in height are not uncommon. The stems are wrapped in alternating leaves with no stalks in varying shapes. Some are shaped like a lance and finely toothed. These can measure up to five inches in length. Others are elliptical and can be between two and six inches long.

They are primarily found in shades of blue or purple. However, plants with white flowers are also available. In addition, crosses with cardinal flowers may result in plants that produce pink blooms.

Blue Lobelias Blooming Season

This wildflower generally unfurls its blooms in midsummer or later and continues the show until fall. In many regions, you can enjoy the flowers from July through October.

Exotic Flowers

They are unique flowers that put on a fantastic show, so they're an excellent choice when you want something big, bold, and beautiful. They attract hummingbirds, butterflies, and pollinators. They flourish along ponds and water features, are favorites in borders, thrive in rain gardens, and delight when paired with plants like ferns, heuchera, or cardinal flowers. 

 It prefers a balanced fertilizer, a 10-10-10 mix that should be applied monthly during the growing season. Organic compost also improves the soil and promotes healthy flowers.

 It can be grown in moist, well-drained soil in partial to full sun. It is suitable for borders, rain gardens, or near streams.

 They require consistent watering as they thrive in moist soil. Remove withered flowers to encourage consistent blooms. Trimming back the stems after the flowering period helps to increase growth.

 Can I grow It in containers?

 It can be grown in containers with excellent drainage and fertile soil. Potted plants need watering more often than those growing directly in the soil since they dry out much faster.

 Blue Lobelia is a short-lived perennial that lasts only 2 to 3 years. However, it readily self-seeds, so new plants will sprout season after season.

This Is How Your Plants Will Look upon Delivery

Bloom Season

Summer

Bloom/Foliage Color

Blue

Height at Maturity

Over 12"

Care

Blue Lobelia thrives in well-drained, consistently moist soil. Regularly water to moisten the soil, especially during hot, dry periods. Fertilize lightly in early spring, and remove spent flowers to encourage continuous blooming—mulch to retain moisture and suppress weeds.

Plant Reproduction

Blue Lobelia spreads by reseeding, dividing clumps, or taking cuttings.

Planting bare-root perennials is best in any season if they are dormant; we only sell dormant plants. Planting them year-round is also excellent if you can get dormant perennials. When your bare-root perennials arrive, soak the roots in water for a few hours to rehydrate them. Lant by digging a hole wide enough to spread the roots comfortably and deep enough to place the top portion crown (where the roots meet the stem) at or slightly above ground level. Position the plant in the hole, backfill with native soil, and gently firm the soil around the roots—water well after planting to settle the soil around the plant and eliminate air. Apply a 2-3 inch layer of mulch to keep weeds at bay and moisture locked in, keeping the mulch away from the crown. Irrigate plants regularly during the first few weeks of drought; never water in full sun, and water late in the evenings to ensure the roots are established well. Fertilize sparingly in the first year, using a balanced, slow-release fertilizer in subsequent years as needed. 

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We only accept returns on plants verified dead. If you think your plants have died, we offer a 1 year warranty, please use use this File a Claim Link to verify dead plants and start with return warranty process.