Delphinium exaltatum

Tried and Trouble-free Recommended by 1 Professionals
Species Native to Missouri
Common Name: tall larkspur
Type: Herbaceous perennial
Family: Ranunculaceae
Native Range: Eastern United States
Zone: 5 to 7
Height: 4.00 to 6.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: July to September
Bloom Description: Gentian blue
Sun: Full sun
Water: Medium
Maintenance: Medium
Flower: Showy
Attracts: Butterflies
Tolerate: Deer

Culture

Best grown in fertile, medium moisture, well-drained soils in full sun. Appreciates some afternoon shade in hot summer climates. Needs protection from strong winds. Fertilize regularly. Remove spent flower spikes to encourage additional bloom and/or a possible second, albeit sparse, autumn bloom. Dislikes the hot and humid climates of the deep South, but generally has better tolerance for these conditions than most of the delphinium hybrids. May be grown from seed.

Noteworthy Characteristics

Tall larkspur is native to Eastern North America from Pennsylvania and Ohio south through the Appalachians into northern Alabama, with several small, isolated populations existing in the Ozarks in far south central Missouri. The Missouri populations are known to occur on wooded limestone slopes above the Jack's Fork and Current Rivers in Shannon and Howell Counties. Tall larkspur typically grows 4-6' tall and features loose terminal racemes of gentian blue flowers which bloom in summer. Individual flowers (to 1" long) are complex and asymmetrical and feature five sepals, one of which is spurred into a distinctive prong resulting in the common name. Palmately divided, 3-5 lobed, deep green leaves. This species is taller, blooms later and has more abundant foliage than most other native U.S. larkspurs. As is the case with many of the buttercup family members, all parts of this plant are poisonous.

Problems

Susceptible to powdery mildew, botrytis blight, leaf spots and crown rot. Slugs and snails are sometimes visitors. Taller plants may require support. Larkspurs generally grow best in cool summer climates.

Garden Uses

Borders. Cottage gardens. Native plant areas. Best massed or in small groupings.