Larkspur Fast Facts

Larkspur, a member of the delphinium family, is a fast-growing garden favorite. Native to Europe, it has naturalized throughout North America. When planting larkspur, keep in mind that the seeds and leaves are poisonous if eaten. While mildly toxic to people or pets, larkspur is particularly dangerous to cattle.

Botanical Name

The most commonly grown species of annual larkspur is Delphinium ajacis. Delphinium elatum is a perennial form of larkspur that has similar growing requirements.

Habit

Larkspur’s tall, upright habit makes it a good choice for fence lines and the back of the border. Flower spikes can reach heights of 36 to 72 inches.

Color

Larkspur blossoms appear in shades of pink, white and deep blue. Foliage is lacy and dark green. Larkspur may require staking.

Hardiness and Range

Rocket larkspur is an easy-to-grow, self-seeding annual. It prefers average soil and full sun in zones 4 to 7. Perennial larkspur benefits from winter protection below zone 5.

Range

Plant larkspur in well-drained soil. It likes to be moist but the bases can rot if the soil is too wet.

Uses

Larkspur flower spikes are used in fresh cut and dried arrangements. Bloom time is April through September.

Kill Larkspur

Pull larkspur plants by hand if you have only a few of the plants in your yard. Wear gardening gloves, and thoroughly wash your hands and clothing after handling the plants. Mow large patches of larkspur before the plants go to seed. Apply an herbicide containing glyphosate according to the herbicide package's directions.