Larkspur is the common name for plants in the genus Delphinium, which has hundreds of unique species that can be found throughout the Northern Hemisphere and in parts of Africa as well. Numerous cultivars have been domesticated for gardens throughout the world, and larkspur is particularly associated with old fashioned English gardens. All larkspurs have deeply lobed leaves which grow close to the ground, coupled with tall stalks of densely concentrated flowers, and tend to bloom in the early spring. Many larkspurs have spurred flowers which resemble the feet of birds, and the stalks can sometimes grow as high as seven feet (a little over two meters) in height.
Depending on where larkspur is found growing, it can be an annual or perennial. Because the plants are highly susceptible to frost and extreme heat, they tend to favor moderate climates, and will die back in the heat of summer. If the winter is mild enough, the larkspur will survive to bloom into the next year. Because larkspur forms rhizomes, or sprawling networks of roots and sprouts, it will spread readily in mild conditions, and gardeners can also separate the rhizomes to encourage the plant to spread. Larkspur can also be found at very high elevations, and the taller growing varieties of the plant appear to prefer the height, reseeding themselves every year.
The flowers range in color from white to pale pink to lavender to blue, and some exotic hybrids have been bred with striking color combinations like rich violet flowers with white centers. The plant prefers full sun to partial shade and moist soil while it is growing, and will grow in almost any USDA zone, depending on the varietal. Most gardeners start larkspur from seed directly in the garden, because the plant will experience transplant shock otherwise. If starting larkspur in a greenhouse, use biodegradable peat pots, which can be planted directly into the soil.
Larkspur is also toxic, and gardeners with grazing animals should take care to plant larkspur out of their reach. The plant is apparently quite palatable, and also high in calcium, so some animals will eat it to correct dietary deficiencies. Cows, especially, have been known to die after eating only small amounts of the attractive plant, and many people who pasture cows wait until the heat of summer to let them out onto fields where larkspur blooms, as the majority of the plants will have died back at that point.