Delphinium

Species with short stems and few flowers such as Delphinium nuttallianum and Delphinium bicolor appear in habitats like prairies and the sagebrush steppe. Tall and robust species with many flowers, such as Delphinium occidentale, appear more often in forests.[9]

Flowers of most species have five spreading sepals and four petals (e.g. Delphinium nuttallianum).

In high mountain habitat, central Utah rangelands

The leaves are deeply lobed with three to seven toothed, pointed lobes in a palmate shape. The main flowering stem is erect, and varies greatly in size between the species, from 10 centimetres in some alpine species, up to 2 m tall in the larger meadowland species.

In June and July (Northern Hemisphere), the plant is topped with a raceme of many flowers, varying in colour from purple and blue, to red, yellow, or white. The flowers are bilaterally symmetrical and have many stamens.[9] In most species each flower consists of five petal-like sepals which grow together to form a hollow pocket with a spur at the end, which gives the plant its name, usually more or less dark blue. Within the sepals are four true petals, small, inconspicuous, and commonly coloured similarly to the sepals. The uppermost sepal is spurred, and encloses the nectar-secreting spurs of the two upper petals.[10]

The seeds are small and often shiny black. The plants flower from late spring to late summer, and are pollinated by butterflies and bumble bees. Despite the toxicity, Delphinium species are used as food plants by the larvae of some Lepidoptera species, including the dot moth and small angle shades.

Delphiniums can attract butterflies and other pollinators.[15]

Delphiniums displayed at the Chelsea Flower Show

A Delphinium cultivar

Various delphiniums are cultivated as ornamental plants, for traditional and native plant gardens. The numerous hybrids and cultivars are primarily used as garden plants, providing height at the back of the summer border, in association with roses, lilies, and geraniums.

Most delphinium hybrids and cultivars are derived from D. elatum. Hybridisation was developed in the 19th century, led by Victor Lemoine in France.[16] Other hybrid crosses have included D. bruninianum, D. cardinale, D. cheilanthum, and D. formosum.[17]

Numerous cultivars have been selected as garden plants, and for cut flowers and floristry. They are available in shades of white, pink, purple, and blue. The blooming plant is also used in displays and specialist competitions at flower and garden shows, such as the Chelsea Flower Show.[18]

The 'Pacific Giant' hybrids are a group with individual single-colour cultivar names, developed by Reinelt in the United States. They typically grow to 1.2–1.8 m (4–6 ft) tall on long stems, by 60–90 cm (2–3 ft) wide. They reportedly can tolerate deer.[15] Millennium delphinium hybrids, bred by Dowdeswell's in New Zealand, are reportedly better in warmer climates than the Pacific hybrids.[19][20] Flower colours in shades of red, orange, and pink have been hybridized from D. cardinale by Americans Reinelt and Samuelson.[17]

All parts of these plants are considered toxic to humans, especially the younger parts,[2] causing severe digestive discomfort if ingested, and skin irritation.[2][3][10][63] Larkspur, especially tall larkspur, is a significant cause of cattle poisoning on rangelands in the western United States.[64] Larkspur is more common in high-elevation areas, and many ranchers delay moving cattle onto such ranges until late summer when the toxicity of the plants is reduced.[65] Death is through cardiotoxic and neuromuscular blocking effects, and can occur within a few hours of ingestion.[66] All parts of the plant contain various diterpenoid alkaloids, typified by methyllycaconitine, and are very poisonous.[63]

The juice of the flowers, particularly D. consolida, mixed with alum, gives a blue ink.[67]

All plant parts are poisonous in large doses, especially the seeds, that contain up to 1.4% of alkaloids.

Wikimedia Commons has media related to Delphinium.

Wikispecies has information related to Delphinium.

• GRIN: Species in the genus Delphinium' — with links by species for information + synonyms.
• USDA-ARS: Larkspur—Delphinium spp. Fact Sheet — native U.S. species and grazing toxicity.
• MBG—Kemper Center for Home Gardening: Delphinium "Pacific Giant Hybrids" — horticultural information.
• Dowdeswell's Ltd: "Growing New Millennium Delphiniums in the U.S. & Canada" — horticultural information.