Delphinium grandiflorum: A Tale of Swallow-Inspired Elegance

Delphinium grandiflorum: A perennial herb of the Ranunculaceae family and Delphinium genus, noted for its distinctive flower shape, reminiscent of swallows, hence its other names of Swallow Grass or Dove Flower.

The flowers have a diameter of approximately 4cm and bloom from May to October. The petals are blue, hairless, and round at the top.

The degenerated stamens are blue, with nearly round or broad ovate petals, whole or slightly concave at the top, and yellow beards in the center of the ventral surface. The pistils are hairless.

There are three carpels, and the ovary is densely covered with short appressed hairs. Delphinium flowers are primarily blue-violet or light purple, resembling blue swallows landing on branches, which is why they are also called “Swallow Grass.”

They are valuable blue floral resources with high ornamental value. Delphinium was horticulturally cultivated in some European countries as early as the 17th century, and thousands of ornamental cultivars have been developed globally, widely used in courtyard greening, pot ornamental, and cut flower production.

I. Morphological characteristics

It’s a perennial herb without tuberous roots. The stem is 35-65cm high, and both the stem and petiole are covered with short reflexed hairs, sometimes hairless on the upper part, with equally spaced leaves and branches.

Basal leaves and lower stem leaves have long stalks; the leaf blade is round-pentagonal, 2.2-6cm long and 4-8.5cm wide, tripartite, with the center lobe nearly diamond-shaped, tripartite near the midrib, and the small lobes linear to lanceolate, 0.6-2.5(-3.5)mm wide, slightly curled when dry, the lateral lobes fan-shaped, unequally bifid near the base, sparsely covered with short soft hairs or nearly hairless on both sides; the petiole is 3-4 times the length of the leaf blade, with a short sheath at the base.

The raceme has 3-15 flowers; the lower bracts are leaf-like, the other bracts are linear; the pedicel is 1.5-3.8cm long, and the axis is densely covered with appressed white short soft hairs; the small bracts are born on the middle or upper part of the pedicel, linear or filamentous, 3.5-7mm long; the calyx is purple-blue, ovate or broad ovate, 1.2-1.8cm long, with short soft hairs on the outside, the spur is rhombic, 1.7-2(-2.3)cm long, straight or slightly curved downwards at the end; the petals are blue, hairless, and round at the top; the degenerated stamens are blue, with nearly round or broad ovate petals, whole or slightly concave at the top, and yellow beards in the center of the ventral surface; the stamens are hairless; there are three carpels, and the ovary is densely covered with short appressed hairs.

The achene is straight, 1.4-1.9cm long; the seed is inverted tetrahedral, about 2mm long, winged along the ridge. It blooms from May to October.

II. Distribution range

It grows on mountain grass slopes or hilly sandy lands at an altitude of 500-2800 meters. It can also be found in the Siberian region of the Soviet Union and the Mongolian People’s Republic.

III. Growth Environment

This plant thrives in cool, well-ventilated, and sun-drenched dry environments and well-drained sandy loam. It is a drought-tolerant and light-loving species. It prefers full sun to partial shade, is robust, drought and cold tolerant, prefers cool climates, and is intolerant of heat.

IV. Growth and Reproduction

Division

This can be done in both spring and fall. Choose a vigorous mother plant, carefully cut into several offshoots at the base using a tool, and transplant directly into pots or fields, thoroughly watering. If possible, set up a shade shed for one week.

Cuttings

In the spring, when new buds grow to 15-18 cm, choose robust branches and leaves (leaving only 2-3 leaves) and insert them into a seedbed (preferably sandy soil). Once rooted, transplant into pots or fields. New branches from the base can also be taken for cuttings after flowering.

Seed sowing

In September-October, collect full and healthy wild Delphinium seeds and store them in low-temperature sand. Sow in the following spring (March-April), with a germination temperature of around 15°C.

For autumn sowing in late September-early October, first sow in an outdoor seedbed, then move to a cold bed or cold room before winter. Transplant in spring when 2-4 true leaves have emerged, and keep a plant spacing of 25-50 cm when 4-7 true leaves have appeared.

Apply sufficient base fertilizer before planting, with nitrogen-based fertilizer as the top dressing. Weakened, aged plants should be transplanted once every 2-3 years. To prevent tall plants from falling over or bending, control water during the seedling stage.

Moreover, during the artificial breeding process of collecting wild seeds, note the germination characteristics of wild Delphinium (requiring vernalization). Successful seed germination and breeding can be achieved by treating the seeds with the low-temperature sand storage method.

For Delphinium offshoots reproduced by division, ensure low-temperature stimulation of growth points to form flower buds.

V. Pest Control

Common diseases include black spot disease and stem rot disease.

VI. Principal Value

Landscape

Delphinium, with its mostly blue-purple or light purple flowers resembling blue swallows scattered on branches, also known as “Swallow Herb,” is a precious blue flower resource with high ornamental value.

Some European countries have been cultivating Delphinium since the 17th century, and thousands of ornamental varieties have been bred worldwide, widely used in garden greening, potted ornamental plants, and cut flower production.

Medicinal

Root: bitter, cold. Toxic. Clears heat and relieves pain, kills parasites. Gargling is used for toothache due to wind-heat. Whole plant: externally used for scabies. Seeds: used for asthma.

VII. Plant Culture

Flower language: tranquility, lightness, justice, freedom

Blue: hesitation

Purple: admiration and compliance

Pink: poetic freshness

White: refined elegance