Larkspur Delphinium elatum 'Sweethearts' (New Millennium Series)

Water

Larkspur, which is the common name for Delphinium elatum 'Sweethearts', should be watered thoroughly and allowed to dry slightly between waterings. The method of watering should be such that the soil is soaked to a depth of at least 1 inch, using a slow trickle from a watering can or hose to avoid water splash on the foliage, which could lead to fungal diseases. During active growth in spring and summer, watering once a week with approximately 1 gallon per plant should be sufficient, but this needs to be adjusted based on rainfall, temperature, and soil conditions, as they prefer consistently moist soil. Avoid overhead watering to prevent mildew and other fungal issues. During hot spells or periods of drought, you may need to water more frequently to maintain the soil moisture.

Light

Larkspur thrives best in full sun to light shade, with at least 6 hours of direct sunlight each day being ideal. An optimal spot for this plant would be one where it receives ample morning sunlight, which is gentler, while being protected from the intense heat of the midday sun. If grown in too much shade, the plant will not bloom as vigorously, and the stems may become weak and floppy.

Temperature

Larkspurs prefer a cooler climate, ideally between 50°F and 75°F, and are hardy in USDA zones 3 through 7. They can withstand a minimum temperature as low as -30°F, but the foliage and flowers will die back once temperatures reach freezing point. They do not fare well in very hot summer climates, where temperatures consistently exceed 90°F, as they may enter dormancy or suffer heat stress.

Pruning

Pruning larkspur involves deadheading spent flowers to promote a second blooming and to prevent self-seeding, if not desired. It's advisable to cut back the flower stalks to the ground once all the blooms have faded, usually in late summer or early fall. You may also want to stake tall varieties early in the season to prevent wind damage. Pruning is usually done after the first growth in late spring or early summer and potentially again after a second bloom.

Cleaning

As needed

Soil

Larkspur 'Sweethearts' prefers well-draining soil enriched with organic matter, with a pH range of 6.0 to 7.5. A mix of loamy soil, compost, and a bit of sand can provide the ideal growing conditions to ensure proper drainage and fertility.

Repotting

Larkspur 'Sweethearts' doesn’t typically require repotting as it is usually grown as an annual or biennial. Instead, renew the plant by sowing new seeds each year or every other year.

Humidity & Misting

Larkspur 'Sweethearts' thrives in moderate humidity conditions; however, it does not require any special humidity adjustments when grown outdoors.

Suitable locations

• Indoor

  Ensure bright light, cool temps, and moist soil for indoor Larkspur.

• Outdoor

  Plant in full sun, provide moist soil and stake tall varieties of Larkspur.

• Hardiness zone

  3-7 USDA

Life cycle

The life cycle of Delphinium elatum 'Sweethearts', commonly known as Larkspur, begins with seed germination, typically in late winter or early spring, requiring a period of cold stratification for successful sprouting. The seedlings then develop into a rosette of basal leaves as the plant progresses into the vegetative stage. As the plant matures, it sends up tall spikes adorned with heart-shaped flowers in shades of pink, blue, and purple, usually in late spring to early summer. After pollination by insects like bees and butterflies, the flowers produce small seed pods that eventually dry and release seeds for the next generation. During the fall or in response to harsh conditions, the plant may go dormant, with the above-ground foliage dying back, while the root system remains alive to sprout again the following season. In the right conditions, Larkspur can also self-seed, allowing it to naturalize in the garden.

Propogation

• Propogation time

  Spring to Summer

• For the Delphinium elatum 'Sweethearts,' a popular member of the New Millennium Series, the most common method of propagation is by seed. The best time to sow seeds is in the spring after the danger of frost has passed or early in the winter if sowing under glass in cold frames. To propagate by seed, prepare a well-draining soil mix in a flat or container, surface sow the fine seeds, and lightly cover with soil or vermiculite. The container should be kept moist but not waterlogged and placed in a location with bright but indirect light. Germination typically occurs within 2 to 3 weeks at a temperature of 65 to 75 degrees Fahrenheit (18 to 24 degrees Celsius). Seedlings can then be transplanted into individual pots when they are large enough to handle and eventually moved outdoors once they have been properly acclimatized to outside conditions. This method allows for a high volume of new plants, but it's worth noting that plants grown from seed may not always come true to the parent's characteristics due to genetic variability.