DELPHINIUM. Larkspur. Europe, North America, Asia. Showy perennials with roundish basal leaves, often cut or divided palmlike. From these issue erect, sometimes very tall stalks carrying many spurred blossoms with large petal-like sepals, normally deep purple or blue to white in color. Their blooming season varies, though it tends to be extended by the cool summers of the coast and cut off by intense heat. Often they can be coaxed into repeated displays by cutting down the stalks as the flowers wither. Sun or light shade, well drained fertile soil, regular watering in most cases. The following are hardy to below 0o except as noted.
cardinale, Scarlet larkspur, is one of the showiest of the many Californian species, though unfortunately not one of the easy delphiniums to grow. It has leafy stems as tall as 6’, though typically a little more than 3’. The leaves are quite large and usually narrowly divided. In late spring and early summer large torches of scarlet blossoms marked with yellow, individually smallish but spectacular en masse, top the stems. This species tolerates poor soil and prefers total drought after blooming. Hardiness is uncertain; probably around 15oF.
cheilanthum. Garland larkspur. Bushy plants branching freely at the base and producing many flowered, slender 2-3’ stems of 2" blossoms. ‘Belladonna Improved’ has sky blue blossoms. Those of ‘Bellamosum Improved’ are colored deep blue-purple. ‘Casa Blanca’ is a pure white-flowered strain.
elatum hybrids. Candle larkspur. These are the familiar, large flowered hybrids with dense “candles” of flowers on sturdy stalks, 6’ or more high in the Pacific Giants series. Traditional favorites are ‘Black Knight’, with rich blue-violet flowers; ‘Galahad’, dressed in pure white; and ‘Summer Skies’, with sky-blue flowers. Unfortunately, these can be a bit overwhelming in smaller gardens. Several recent seed strains address this problem, offering a similar color range and flowers nearly as large on stems under 3’ tall. ‘Blue Fountains’ is a dwarf strain featuring plants with blooming stems under 30" high, while those of ‘Stand Up’ are 2’ high or less. In both cases, flower colors range from snow white to navy blue and violet.
nudicaule. Scarlet larkspur. Like D. cardinale, whose common name it shares, this is a showy, red flowered native. However, the plants are usually less than half the height of D. cardinale, generally 2’ or less. It also has more slender, graceful stems and somewhat larger flowers. The flowers are various, pleasing shades of red, marked with yellow. Plants of our current seed strain are considerably more vigorous and floriferous than is usual for this species. Drought tolerant and probably hardy to 0-10oF.