Summer Nights (Delphinium)
Latin Name: Delphinium grandiflorum
Item #: 877B
Suitable for Containers:
Extra Dwarf Delphinium
Plant Height 10 - 12 in/23 - 30 cm Perennial - Hardiness zones 3 - 7 Delphinium grandiflorum - An unique extra dwarf type with a lacy leaf plant which is covered with small single blooms about the size and shape of an impatiens. The Summer Nights series blooms earlier and has more summer heat tolerance than other strains of this type. It makes an excellent pot plant and looks good in mixed containers and dwarf perennial borders. This species likes full sun and well drained, sandy soil. Plants bloom June through early August. Use as an annual in southern USA, below zone 8 (AHS Heat zone 6 - 1). Plants do not require vernalization to bloom the first season.
CULTURE: Approx. 22,700 seeds per oz/28 gr. For June blooms sow indoors Dec 15 - Jan 30 @ 68-72°F/20-22°C soil temp. Cover seed lightly and maintain slightly moist humidity levels for 14 to 18 days. As seedlings appear, gradually lower humidity levels and soil temps to 64-68°F/17-20°C. As plants become established, lower temps to 55-62°F/13-17°C. Transplant seedlings 6 - 8 weeks after sowing into 4 in/ cm pots. Use 3 plants per pot for larger gallon containers. Do not plant seedlings too deep. Use soil with a pH of 6.5 - 7. Begin fertilizing at about 200 ppm with a fertilizer like 20-10-20 that contains a nitrate type nitrogen. Avoid soluble salt build-ups. Do not crowd plants too tight - provide good ventilation. As plants reach maturity in early May, maintain air temps, and grow plants on the dry side, @ 75°F/24°C days and 45°F/7°C nights. Temperatures above 85°F/29°C will cause blooms to drop off the plant. Temperatures below 55°F/13°C in southern USA under short day length may delay flowering and some resetting. Transplant mature plants outdoors in full sun in well drained, sandy soil.