Delphinium: Larkspur
Tall spikes of Delphinium are the stars of English-style perennial borders and old fashioned cottage gardens.
Plant care & info
Family: Ranunculaceae
Genus: Delphinium
Common Name: Larkspur
Northern Hemisphere, with many species native to the western United States.
Delphinium prefers sites that receive at least six full hours of sun and protection from the wind. Plant in well-drained soil amended with organic matter. Space plants at least two feet apart.
This herbaceous perennial is very hardy and tolerant of frosts. It dies to the ground every winter and wakes up early in March. Delphiniums are short-lived perennials and often need to be replaced every 2 to 3 years, especially when planted in heavy soils.
Most hybrids flower early to mid summer. Immediately after flowering, remove the flower stalk. Cut off the spikes under the first bottom floret, then allow the green stems and the foliage to die down naturally. This will encourage additional flower spikes in late summer or early fall. Thinning is essential for delphiniums. First year seedlings should have only one flower spike.
Second year plants should only be permitted to have three flower spikes. Older and established delphiniums should be permitted to have only five flower spikes. Staking is helpful for delphiniums, and the best way to do it is by containing the stems of the plant, not the flower spike.
These heavy feeders appreciate soil rich in compost, well-rotted manure, and regular use of a balanced 10-10-10 fertilizer. During the growing season, they require deep watering at regular intervals. Mulching around plants will keep their roots moist and cool.
Attracts birds, butterflies and hummingbirds. Deer resistant. Great cut flowers.
Slugs can be problematic in the cool wet spring as plants break dormancy. “Sluggo” is organic slug control bait. To prevent powdery mildew and black spot, place plants in an open airy position to promote circulation. To control powdery mildew and black spot use an organic fungicide with sulfur. In winter, waterlogged soil will cause the crown to rot, hence the need for excellent drainage.
The presence of cyclamen mites can result in stunted and deformed plants with buds that turn black. Practice good sanitation by removing and destroying infected and infested plant debris.
The modern Delphinium is a result of hybridization of Delphinium species from many parts of the world.
A member of the buttercup (Ranunculaceae) family, Delphinium consists of around 250 species of annuals, biennials, and perennials. Delphinium comes from the Greek word for dolphin, a reference to the new flower bud’s resemblance to the bottle-like nose of the dolphin.
In Tudor England, some of the species grown were referred to as larkspur, possibly because the nectar sepal looked somewhat akin to a lark’s claw. The common name larkspur also applies to a similar looking yet different plant called Consolida ajacis.
Delphinium flowers may be single or double, and blue is the most common color—although red, pink, white, and violet flowered varieties are also available. Many flowers have white or black centers known as “bees.”
Flowers occur in regal spikes with numerous flowers on each spike. The spikes of most delphiniums make attractive, long-lasting cut flowers. The foliage is palmately lobed and is divided into 3 to 7 parts, depending upon their location on the stem.
Mature plants can reach 6 to 9 feet tall, though dwarf varieties can grow 3 to 4 feet.. Placing the tall plants in the background of a perennial bed is often a popular choice. Delphinium can also be used as specimen plants or as a small grouping in the garden.
Explore More Larkspur
Aurora Series
Delphinium elatum Aurora Series
A newer group of hybrids with excellent uniformity, vigor, and sturdy stems. Semi-double flowers present in shades of blue, purple, lavender, and white in summer. Grows 3-4′ tall and wide. Zones 3-8.
Guardian Series
Delphinium elatum Guardian Series
A Pacific Giant hybrid that grows 24 to 36 inches tall and wide. Flowers are shades of blue, lavender, and white. Hardy in zones 4-8.
Magic Fountain Mix
Delphinium elatum Magic Fountain Mix
Bushy plants are 3 feet tall and 2 feet wide, with blue, lilac and white flowers in June. Well suited for windy areas.
New Millennium Series
Delphinium elatum New Millennium Series
This English hybrid was bred for exceptional garden performance, and has sturdy, strong-stemmed spikes packed with loads of richly colored flowers. Flowers are often double or semidouble and can re-bloom during a single season. Grows 6 feet tall and 2 feet wide. Zones 3-8.
Pacific Giant Hybrids
Delphinium elatum Pacific Giant Hybrids
Spikes of semi-double blue, lavender, pink, white and bi-color florets. Grows 4 to 6 feet and can re-bloom in a single season. Zones 3-8.
Blue Butterfly
Delphinium grandiflorum ‘Blue Butterfly’
Cobalt blue flowers from May through August. Grows 12-18″ tall by 18″ wide. Great in containers. Zones 3-8.
DeRosso Red
Delphinium nudicaule ‘DeRosso Red’ (Red Larkspur)
Vibrant flowers in a most unusual color for delphiniums are irresistible to hummingbirds and butterflies. Compact, bushy plants are 10 to 14 inches and bloom in May. Prefers dryish, rocky, well-drained soil. Beautiful at a garden’s edge, rock gardens or in patio containers. Zone 5.
