Flower induction and cultural requirements for quick-cropping of the herbaceous perennials Veronica spicata, Phlox paniculata, Leucanthemum x Superbum, Achillea, Gaura lindheimeri, and Campanula

Optimized production of vegetatively propagated herbaceous perennials requires a proper knowledge of stock plant management, propagation protocols, appropriate vegetative bulking, and flower induction and development requirements. This project was conducted to identify these physiological and cultural elements for six herbaceous perennial species. Stock plant management, propagation, and vegetative bulking for Veronica spicata ‘Red Fox’ and Campanula ‘Birch Hybrid’ required only appropriate light and temperature because both plants were day-neutral following a flowering flush. Plants had an obligate cold requirement for flowering. Photoperiod control during all stages of development was necessary for Phlox paniculata ‘David’, Leucanthemum xsuperbum ‘Snowcap’, Achillea ‘Moonshine’, and Gaura lindheimeri ‘Whirling Butterflies’ because all were long-day plants with facultative cold requirements for flowering. Experiments were conducted to quantify the effects of propagation environment on rooting and subsequent flowering of P. paniculata ‘David’. Rooting increased as daily light integral increased from 0.8 to 8.6 mol•m−2•d −1 but was not affected by auxin concentration or rooting photoperiod. Days to flower decreased up to 17 days as propagation photoperiod increased from 11 to 15 hours, and cold treatment for 5 weeks decreased time to flower by up to 25 days.