Native Plant: Colors explode in the garden with great blue lobelia

Editor’s note: Once a month OSU Extension Master Gardener Volunteers in Franklin County profile a plant that occurs naturally in central Ohio.

A great variety of blue-flowering perennials predominate in spring and early summer. The great blue lobelia is a delight in the mid- to late-summer garden.

The bright blue flowers of Lobelia siphilitica brighten many perennial beds from July to late September or early October.

This hardy native is a clump-forming perennial that sends up a stiff, unbranched stalk 2- to 3-feet high. Five-inch-long leaves form toward the bottom of the plant and become smaller as they ascend the stalk. Leaves are light green, lance-shaped and finely serrated at the edges.

Atop the stalk, thinly bell-shaped flowers are borne on an upright spike, blooming sequentially from bottom to top. Each flower bears five petals, or lips. The bottom three lips provide a platform for bees and other pollinating insects.

Native Plant: Common boneset is perfect for rain gardens

Butterflies will visit this plant, and hummingbirds are similarly attracted. The long-lasting flowers range from light blue to dark blue-violet in color. White-flowering specimens are occasionally found.

Spent flowers give way to capsules producing small seeds that are dispersed by wind and sometimes water. A generous self-seeder, great blue lobelia, will naturalize in areas with suitable growing conditions.

It is useful for pollinator and woodland gardens and is a great plant for rain gardens and wetland areas. Its shade tolerance makes it especially useful in many gardens. Brief periods of flooding are tolerated, as is occasional drought.

The lobelias are a large group of plants, with more than 40 species native to North America. Lobelia siphilitica is found widely throughout the eastern and central U.S. Its typical native habitat includes moist meadows, woodland bottoms and edges, stream and pond edges and swales and ditches.

Tissues of great blue lobelia contain toxic alkaloids, which discourage browsing by mammals. While all parts of this plant are toxic, it was used medicinally by Native Americans for colds, fevers, stomach ailments and respiratory issues. European settlers considered it a cure for venereal disease, hence the species name.

While not as common in gardens as its red-flowering cousin, Lobelia cardinalis, great blue lobelia is nonetheless available through many garden centers and native plant nurseries.

Native Plant: Chokecherry is a plant for all seasons

Growing conditions

Hardiness zones: 4-9

Sun: Part shade preferred; tolerates heavy shade

Water: Performs best with consistent moisture

Soil: Organically rich loam; tolerates clay soil

Maintenance: Easy to care for; deadheading will encourage reblooming

Propagation: By seed and division

Pests and diseases: None of significance

This article originally appeared on The Columbus Dispatch: Native Plant: Great blue lobelia brightens garden beds in the summer