Larkspur Giant Imperial reaches a height of approximately 60 - 90 cm and produces sturdy, upright flower spikes densely covered with striking blooms. Its elegant, vertical growth habit makes this annual an excellent choice for the middle or back of borders, while it also performs beautifully along fences, walls, or hedges. In a sunny, sheltered location, it flowers profusely from early summer throughout the summer. The mix contains various shades of blue, purple, pink, and white, making it easy to combine with other flowering garden plants. It pairs beautifully with cosmos, coneflowers (Echinacea), oxeye daisies (Leucanthemum), perennial salvias (Salvia), catmint (Nepeta), foxgloves (Digitalis), and poppies (Papaver). Ornamental grasses such as Stipa tenuissima also create an attractive contrast with the stately flower spikes and give borders a natural appearance.
Besides its ornamental value, Giant Imperial is highly appreciated as a cut flower. The long flower spikes are perfect for colourful bouquets and can also be dried, retaining much of their decorative shape. During flowering, the blooms attract many bees, bumblebees, and butterflies, making larkspur a valuable addition to wildlife-friendly gardens. Non hardy biennial. Height: 60 - 90 cm.
Warning: All parts of the plant are poisonous.
Indoor sowing: February - end of March
Outdoor sowing: mid May - mid July
Germination: 14 - 21 days
Germination temp.: 18 - 21 °C
Sowing depth: ½ - 1 cm
Plant distance: 35 cm
Sowing distance in rows: 35 cm
Plant position: sunny with some shade
Days till flowering: 60 - 90 or 320
Sow from February until the end of March in seed trays, cell trays, or small pots filled with a fine, well-draining seed compost. Sow the seeds ½ - 1 cm deep and lightly cover them with compost. Gently moisten the soil with a spray bottle and cover the tray with a transparent lid or plastic cover to prevent the soil from drying out. Place the tray in a bright location at a temperature of 18 - 21 °C. Keep the soil slightly moist throughout the germination period, but avoid waterlogging. Most seeds germinate within 14 - 21 days.
Remove the cover as soon as the first seedlings emerge. Once the seedlings have developed two to four true leaves and are large enough to handle, transplant them into individual pots. Continue growing them in a bright, cool location to encourage sturdy, compact growth. About one to two weeks before planting outdoors, begin hardening them off by placing them outside for gradually longer periods during the day and bringing them indoors at night. Plant them in their final position after the last frost, from mid-May onwards.
From mid-May until mid-July, seeds can also be sown directly outdoors in a prepared seedbed. Work the soil to a fine tilth, remove weeds, and sow the seeds ½ - 1 cm deep. Firm the soil gently and water thoroughly. Keep the soil evenly moist during germination and weed regularly. Young plants can be transplanted to their final position in October or November. They will first form a leaf rosette, overwinter, and then flower abundantly the following year. Larkspur grows best in a sunny to lightly shaded position with fertile, humus-rich, well-drained soil. In warm locations with intense afternoon sun, some light shade during the hottest part of the day is beneficial. A sheltered position helps prevent the tall flower spikes from being damaged by strong winds. Water regularly during dry periods, especially while the plants are still young. Remove faded flower spikes to encourage a longer flowering period. Taller plants may require support in exposed locations. Ensure good air circulation between the plants, as larkspur can be susceptible to powdery mildew, particularly during warm and humid summers.
