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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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Royal Catchfly, Silene regia, is a prairie forb that is endangered in multiple states. More information on the plant's development and propagation is essential to successful recovery programs. Little is known about S. regia's response to fertilizer or how floral initiation is triggered. Within Caryophyllaceae floral initiation often is linked to photoperiod. The objectives of my study were to investigate how fertilizer affects growth of S. regia to transplant stage and to determine if flowering of S. regia is initiated by photoperiod or developmental age. For fertilizer, treatments consisted of a control, a 20-20-20 liquid fertilizer solution at 1.25 g/L applied weekly, and an Osmocote 14-14-14 four-month slow release solid fertilizer at 14.6 g/L. Various shoot and root parameters were measured. For flowering, treatments of either long day photoperiod (16 hours light/8 hours dark) or short day photoperiod (8 hours light/16 hours dark). Basal rosette leaf number, node number on elongated stems, axillary stem number, and flower bud number were recorded weekly. Overall, fertilizer increased growth relative to the control for shoot and root parameters. Solid fertilizer was better than weekly liquid at producing healthy shoots, but had no difference in root parameters. For long day photoperiod plants, 38.5% had elongated stems, but for short day photoperiod plants, 0% had elongated stems. Short day plants were smaller than long day plants but by week 16 were equal or greater in size, yet still no plants flowered. Plants grew axillary stems and 19.4 ± 8.8 flower buds. Solid fertilizer mixed into the soil was the best for growth. A long day photoperiod triggered floral initiation in S. regia. Future studies should use this information to increase survival in transplants planted into natural areas.