There has been an increasing interest in drought tolerant native flower species for Montana residential landscapes and roadsides. Ratibida columnifera is a drought tolerant, perennial wildflower that can be used in home gardens as well as on roadsides. However, there is no knowledge of how R. columnifera will respond to typical nitrogen fertilization in residential landscapes. Our objective was to determine the correct nitrogen application required for R. columnifera to acquire optimal growth and development. After germinating and transplanting R. columnifera seedlings, nitrogen treatments began with five groups containing six pots in each group. Pots were fertilized with 100 ml of ammonium nitrate at 0ppm N, 25 ppm N, 50 ppm N, 75 ppm N, or 100 ppm N at weekly intervals. All pots were fertilized with 100 mL of 50 ppm potassium phosphate. Three plants from each treatment were harvested 30 days after the start of fertilization treatments and underwent biomass evaluations of their fresh and dry weights. The remaining three pots from each treatment were evaluated at blooming for time to flowering, flower number, and flower quality. R. columnifera biomass at 30 days benefited from 25-50 ppm nitrogen, but did not increase biomass above 50 ppm. Flowering was affected at different levels than biomass and was delayed by high nitrogen.
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