Seedman Basic Info:
Sow Feb. 15th indoors for plants that bloom June to September the first season. Germinate at 60-65°F for 15 days. Press seed into soil. Grow plants at 60-65°F. Centranthus are fast growing and can become too large in a cell pack or pot if not properly grown. Avoid high temperatures, over-fertilizing and over-watering. Prefers average to sandy, neutral or alkaline soil, full sun and long day-length for flowers the first season. Soft spindly growth are results of too rich a soil as well as placement in excessive shade. Can be used as a cut flower. May self-sow freely under favorable conditions so dead-head plants to reduce. Division is required every 3 years to maintain plants vigor and avoid leggy growth. Cutting back hard in midsummer will also deter legginess. Hardy in zones 4-9.