delphiniums

Delphiniums: Different Plant Varieties, How To Grow and Care

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Delphinium is a famed ornamental plant that brings height and a splash of color to home and commercial gardens. Though these plants can sometimes be a challenge because of the maintenance requirements, they remain a favorite of many growers, all thanks to their showy spikes of flowers.

Typically their blooms come in beautiful shades of purple and blue, but other varieties showcase pink, white, red, or yellow instead. Read on to learn more about the facts and different types and cultivated varieties of these stunning perennials.

Delphinium Facts

blue delphinium flowers

Name and Origin of Delphiniums

The name delphinium refers to an entire genus of Delphinium spp. in the botanical family Ranunculaceae or also known as the Buttercup or Crowfoot family. 

The delphinium name comes from the Greek word delphis, which translates to ‘dolphin’ referring to the shape of the plant’s flower buds. 

Another origin of delphinium comes from Greek mythology. According to a legend, the delphinium flower bloomed from the blood of Greek god Aias (or Ajax) as he was killed during the Trojan war. Written on the petals are the letters ‘Ai’ or ‘alas’ in Greek. 

Delphiniums are recognized for their tall stature that makes them an excellent perennial border. Because of this, they are also often referred to as the ‘Queen of the Border.

These plants are native to the Northern Hemisphere and high mountain areas in Africa. Three Delphinium species are under the threat of extinction – the D. leucophaeum, D. oreganum, and D. pavonaceum. These species grow wild in Oregon in the United States. 

The Anderson’s larkspur or known scientifically as D. andersonii is an endemic species to the Sierra Nevada mountains in the western United States while the tall larkspur (D. exaltatum) originates from the Appalachian Mountains in the eastern part of North America. 

While the species mentioned above are from the United States, the D. dasycaulon sub-species is a native to Mozambique in Africa.

Delphiniums vs. Larkspurs

Delphiniums are sometimes referred to as larkspur. It is another common name that is shared with an annual species of the Consolida genus. Some people think that delphiniums are similar to the Consolida larkspur, but the two plants are, in fact, different. 

Larkspur, which is scientifically known as Consolida ambigua, is actually an annual in the same family as delphiniums. The common name ‘larkspur’ depicts the flowers that resemble a lark’s claw or spur. These plants have smaller spikes with fewer florets, and their leaves are deeply cut (1).

Delphiniums, on the other hand, are short-lived perennials. Their spikes are more significant and taller (2).

The Modern Delphiniums

dark blue delphinium

There are over 500 known species of delphiniums in different parts of the world. Like most recognized ornamental plants, these perennials have become a subject of hybridization. 

The results of these hybridizations are the most commonly available delphiniums today. Many plant breeders crossed different delphinium species around the world and came up with better-performing delphinium varieties, as well as delphinium varieties exhibiting new flower colors. Among the breeder-favorite delphiniums is the D. elatum from the Swiss Alps, D. bruninianum from the Himalayas, D. cheilanthum from Siberia, and the D. formosum from Armenia. 


Uses

Garden and Landscape Uses

violet delphinium flowers

Delphiniums are legendary perennial plants that make excellent borders and cut flowers. Because of their alluring spikes and height, they suit well in cottage gardens or gardens with a free design. They can be planted in groupings or mass plantings.

When planted on beds, these perennials blend well with sneeze weeds, fleabanes, phloxes, daylilies, and max chrysanthemums. 

Other Uses

The flower juice of Delphinium consolida is used to make a blue ink when mixed with alum.

Delphiniums are also widely popular as dried flowers. 


Toxicity 

All plant parts of delphiniums are considered highly toxic, but the new growth and the seeds have the highest concentration of toxic substances. Although poisoning in humans is not common, these plants often affect the livestock (5). 

They do not cause contact dermatitis, but the plants contain poisonous alkaloids such as delphinine and ajacine (3). 

The plant, particularly the flowers, leaves, seeds, and stems,  may result in a burning sensation in lips and mouth, vomiting, numbness of throat, diarrhea, weak pulse, respiratory system paralysis, muscle spasms, convulsions, and even death if consumed in high amounts (3). 


General Description and Characteristics

Delphinium plants are herbaceous perennials that add colors to summer gardens with their spectacular spikes of vibrant flowers. Plant height varies depending on the variety, which ranges from 1 to 2 ft (for dwarf varieties) to 6 to 8 ft (tall varieties). 

Delphinium Flowers

light blue delphinium

Delphinium presents a plethora of colors, including true blue, purple, lavender, pink, white (D. elatum), scarlet (D. cardinale), and yellow (D. luteum). The central smaller flowers, which are called ‘bees’ or ‘eyes,’ may appear in white, brown, tan, black, or striped. The flowers are terminal and mostly in elongated clusters or spikes (3). 

Each floret typically has five glabrous petal-like sepals that form a hollow pouch with a distinguished spur at one end. Inside this pouch are the flower’s four true petals. 

Delphinium flowers have different forms depending on the number of their sepals and petals. They can be single, semi-double, or double. 

Single-form delphinium flowers have five sepals. The upper pair of petals are fused to form the nectary, while the lower pair, called “honey leaves,” are typically adorned with colored hairs. 

Semi-double delphinium flowers have a set of five sepals and an additional inner set of eight more. Double delphinium flowers do not necessarily have eyes. Instead, they have a large number of extra sepals.

For more beautiful flowering plants, check our guide here!

Delphinium Fruits

Delphiniums produce follicles, which are dry dehiscent fruit that splits open on one side. Each fruit contains many seeds (3). 

Delphinium Leaves

Delphiniums have compound, green, deeply divided leaves with three to seven palm-shaped lobes (3). The leaves are alternate and long-stalked. 

Delphinium Roots

These ornamentals have relatively shallow roots. Typically, the root system of delphiniums has a crown and two types of roots extending from it- the anchor roots and the feeder roots. 

The crown links the root system and the shoot system of the plants. It holds several eyes from which new flower stems could emerge. 

Anchor roots are the primary roots of the plant. They are thick, brown roots that help secure delphiniums in the soil. Feeder roots, on the other hand, are thin, young roots that take up nutrients and water from the ground. They are within the surface layers of the soil.


Types of Delphiniums

There are numerous delphinium species and cultivars available, and the most popular ones can be categorized into these different groups: the elatum group, belladonna group, grandiflorum group, Pacific Giants delphinium hybrids, and New Zealand delphinium hybrids. 

Elatum Group

violet delphinium

The elatum group contains delphinium cultivars of the Delphinium elatum species. These clump-forming perennials are known by the common names alpine delphinium or candle larkspur. 

Often grown as an ornamental, the elatum group of delphiniums requires extra care and maintenance. They showcase numerous single, semi-double, or double flowers in early to mid-summer. Bloom colors range from blue and purple to white, cream, and pink. They are floriferous but short-lived (4). 

Fully matured D. elatum plants typically reach up to 8 ft in height and spread up to 3 ft. They always require staking as additional support and protection from strong winds.

The elatum group can be further divided into three types: short varieties, medium varieties, and tall varieties. The cultivars ‘Butterball’ and ‘Rosemary Brock’ are just a few examples of popular short varieties of this delphinium group. The ‘Blue Dawn’ and ‘Turkish Delight’ are famed medium varieties. For tall types, some of the popular ones include the ‘Fanfare,’ ‘Mother of Pearl,’ and ‘Boningale Glory.’

Belladonna Group

Another famed group of delphiniums is the Belladonna group, which is also known as the Delphinium sp. Belladonna Group, or Delphinium x belladonna (4). It comprised primarily of hybrids between D. elatum and D. cheilanthum. 

This type of delphinium grows about 3 to 4 ft in height with an upright form and spreads up to 1.5 to 2.5 ft. The flower stalks bloom with branched spikes of single or double flowers in shades of blue or white in early summer.  Correctly cutting back the plants will promote reblooming in late summer to early fall.

This group of delphiniums is moderately challenging to maintain but easier to grow than the elatum group. Some of the most popular cultivars under the belladonna group are the ‘Bellamosum,’ ‘Blue Bees,’ ‘Casa Blanca,’ ‘Piccolo,’ and ‘World Peace.’

Grandiflorum Group

The grandiflorum group of delphiniums is also known as the Chinese delphiniums (D. chinensis) or Siberian delphiniums. Plants in this group are native to Russia and China. They are short-lived perennials.

This group comprises compact, generally short delphinium varieties with a bushy growth habit. They suit drier areas, including rock gardens, and grow up to 1 to 2 ft in height.

Delphiniums from this group present alluring flowers of blue or white, which blooms in mid-summer. While delphiniums in the elatum group produce single spikes of flowers, the grandiflorum group has dispersed flowers. 

Some of the most popular grandiflorum delphinium cultivars are the ‘Blue Butterfly,’ ‘Summer Morning,’ and ‘Blue Mirror.’ 

Pacific Giants

The Pacific Giants group, which is also referred to as the Pacific Hybrids series or Pacific Strain, presents delphinium plants that grow up to 4 to 6 ft in height. The flowers form columnar spikes of single to double florets in a wide range of colors, including blue, white, purple, lavender, and pink. Flowering occurs in summer. 

Popular cultivars from this group include ‘Black Knight,’ ‘Blue Bird,’ ‘Galahad,’ and ‘King Arthur.’

New Zealand Hybrids

Delphiniums from the New Zealand hybrids group are medium-sized perennials. Included in this group are the ‘Pegan Purples’ and ‘Dasante Blue’ cultivars, as well as those in the famed New Millenium series. 


Recommended Delphinium Varieties

Delphiniums offer dozens of eye-catching cultivars such that deciding which one to plant can be quite a hurdle. Summarized below are some of the best delphinium cultivars available. 

Delphinium elatum ‘Pagan Purples’ 

Delphinium ‘Pagan Purples’ or Delphinium elatum ‘Pagan Purples’ (Hybrid Bee Delphinium) stands out with its eye-catching dark bluish-purple florets that form sturdy flower spikes with white or brown bees. Each plant grows up to 4 to 6 ft tall and spreads up to 1 to 2 ft. 

The ‘Pagan Purples’ is a long bloomer cultivar that showcases flowers from early summer to early fall

This delphinium cultivar belongs to the acclaimed ‘New Millenium’ series. 

Delphinium elatum ‘Royal Aspirations’

Also part of the ‘New Millenium’ series from the New Zealand hybrids group is the ‘Royal Aspirations’ cultivar.  The plant grows up to 6 ft tall and 4 ft across, and often require staking for support. It produces multiple tall spikes of flowers in deep sapphire to navy blue with a contrasting white bee. The leaves are deeply-cut.

Delphinium elatum ‘Bruce’ 

One of the most popular delphiniums is the D. elatum ‘Bruce,’ a cultivar that received the RHS Award of Garden of Merit. This herbaceous perennial reaches about 6 ft in height when fully matured. It presents vivid violet-purple blooms with buff eyes and glossy, dark green divided leaves. 

Delphinium ‘Black Knight’

The ‘Black Knight’ delphinium displays semi-double dark purple flowers with dark eyes forming tall spikes and deeply-cut green leaves. Growing 4 to 6 ft in height and 1 ft wide, ‘Black Knight’ often requires staking for support. If unsupported, the stalks of this plant snap easily in strong winds. 

Delphinium ‘Galahad’

Delphinium ‘Galahad’ is part of the famed Pacific Hybrid Series that originated in California. This widely recognized cultivar features spires of pure white blooms and vibrant green leaves. It reaches up to 4 to 6 ft tall and 1 to 2 ft wide. 

Candle Delphinium ‘Galahad,’ as others call it, blooms from early to midsummer. 

Delphinium ‘Red Caroline’

While most delphiniums come in blue or purple hues, the ‘Red Caroline’ cultivar undoubtedly stands out with its unique double bright crimson to reddish-pink flowers that bloom in summer. The foliage is dark green. This delphinium cultivar typically reaches a height of 1.5 to 2 ft and a spread of 1.5 ft after 2 to 5 years. 

Delphinium ‘Princess Caroline’

‘Princess Caroline’ delphiniums are medium-sized cultivar that blends well in the middle or front of any perennial garden. The beautiful blooms also make excellent cut flowers. 

This particular cultivated variety of delphinium presents densely packed spikes of salmon-pink flowers that are streaked with red. It grows up to 2 to 3 ft tall and 1.5 to 2 ft wide. 

Delphinium grandiflorum ‘Delfix Blue’

Delphinium ‘Delfix Blue,’ or also known as Chinese Delphinium ‘Delfix Blue,’ comes from the Delfix Series of delphinium hybrids. 

A dwarf variety, fully matured ‘Delfix Blue’ delphiniums reach more or less 1 ft tall and 0.5 ft wide. It features bushy, compact, and well-branched lacy leaves and loosely arranged single purplish-blue blooms. 

Delphinium ‘Magic Fountain White’

One of the highly recognized white delphiniums is the Delphinium ‘Magic Fountain White’ cultivar. Many adore its majestic large, semi-double pure white florets with contrasting dark eyes. The elegant blooms form dense and sturdy flower spikes and bloom from late spring to late summer. 

This delphinium is a shorter variety and does not require staking. It grows up to about 2 to 3 ft tall and 1 to 2 ft wide. 

Delphinium ‘Faust’

‘Faust’ delphinium, which is also known as candle larkspur ‘Faust’ or candle delphinium ‘Faust,’ is an award-winning delphinium variety that forms long spikes of stunning deep blue-purple spikes of double flowers with black eyes. It is a recipient of the Royal Horticultural Society’s  Award of Garden Merit. 

This variety blooms from early to midsummer. It grows up to 5 to 6 ft in height and spreads up to 2 to 3 ft. 


Culture, Care, and Maintenance

Planting Delphiniums

Delphiniums are short-lived, quick blooming perennials (2) that last only 2 to 3 years in the garden (1). These herbaceous plants are a gardener’s favorite, particularly for cutting gardens, informal gardens, and cottage gardens. They are a great addition to beds and borders, and they make excellent cut flowers with their stunning blooms in different colors. 

Generally, delphiniums are relatively easy to grow but can be moderately tricky to maintain. 

Planting

These herbaceous perennials prefer fertile, well-drained, and medium-moisture soil in full sun to light shade. Plant them in areas that protect them from strong winds. Planting should be done in the spring with 1 to 3 ft spacing between plants. When planting, secure that the top of the root ball is leveled with the soil. 

Watering

Like other perennials, delphiniums would benefit from ample and regular watering. Water deeply when rainwater is scarce, but don’t allow standing water since it causes crown and root rot. Water at the base of the delphinium plant and keep the foliage dry to prevent diseases like powdery mildew. 

Fertilizing

Application of all-purpose fertilizers after planting is advised since delphiniums are known as heavy feeders (2). They should be fed at least twice – first in early spring and another later in the season (1). 

Staking

The stems of delphiniums are hollow and easily break when exposed to strong winds and rain. Because of this, tall varieties require staking. Install stakes early in the growing season to provide early support.

Deadheading

A cultural practice that encourages plants to produce more blooms is called deadheading. It can be done to lateral flowers when the bloom begins to decline, or to the entire stem back to the foliage at the plant’s base if there are no more flower buds. 


Common Pests and Diseases of Delphiniums

Delphiniums are generally easy to grow perennials. However, like any other plant, they also come into contact with a few insect pests and diseases during growth.  

Powdery mildew is a common disease of delphiniums, especially when there are poor air circulation and high humidity. To prevent the occurrence of this fungal disease, keep the foliage as dry as possible, and maintain proper planting space. Other common delphinium diseases include black leaf spot, Botrytis blight, crown rot, and other fungal leaf spots. 

The typical insect pests of delphiniums are aphids, mites, and leaf miners. Cyclamen mites, in particular, result in stunted and deformed plants. Aphids make the leaves curled and distorted. 


What Do Delphinium Flowers Represent?

The meaning and symbolism of delphiniums are quite interesting. They generally symbolize goodwill and cheerfulness. The beautiful blooms bring forth joy and warmth that they make great gifts to cheer up someone. 

Different colors of delphiniums convey different meanings. Blue delphiniums signify dignity, while white, pink, and light blue delphiniums symbolize renewal and youth

These flowers also symbolize an open heart and a passionate attachment.

Delphiniums are the official July birth flower

With their attractive spikes of vivid flowers and equally stunning deeply cut, green foliage, delphiniums are indeed a fascinating addition to any garden. Read more about other interesting flowering plants through our article on the best perennial plants for your garden. 

References

Reference List:

  1. Lancaster.unl.edu. (2020). Delphiniums – A Spectacular Garden Flower (delphinium) | Nebraska Extension in Lancaster County. [online] Available at: https://lancaster.unl.edu/hort/articles/2002/delphinium.shtml
  2. Hinkamp, D. (2020). DELPHINIUMS ARE PRETTY TOUGH – ONE OF THE HARDIEST PERENNIALS IN NORTHERN UTAH. [online] Utah State University Extension. Available at: https://digitalcommons.usu.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1801&context=extension_histall   
  3. Plants.ces.ncsu.edu. (2020). Delphinium (Delphinium, Larkspur, Staggerweed) | North Carolina Extension Gardener Plant Toolbox. [online] Available at: https://plants.ces.ncsu.edu/plants/delphinium/ 
  4. Gardening.cornell.edu. (2020). Explore Cornell – Home Gardening – Flower Growing Guides – Growing Guide. [online] Available at: http://www.gardening.cornell.edu/homegardening/scene09de.html 
  5. Ars.usda.gov. (2020). Larkspur (Delphinium spp.): USDA ARS. [online] Available at: https://www.ars.usda.gov/pacific-west-area/logan-ut/poisonous-plant-research/docs/larkspur-delphinium-spp/ 

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