Nutrient Ranges in Pelargonium ×hortorum and Pelargonium Species

Zonal geranium ( Pelargonium ×hortorum ) and scented geranium ( Pelargonium sp.) together are among the top-selling floriculture plants in the United States today, with several hundred cultivars and species available each year. With such diversity in appearances, growth habits, and developmental traits, we hypothesize a correspondingly wide range of nutritional uptake and partitioning characteristics. Mature leaves from 55 cultivars or breeding lines of zonal geranium and 60 species of Pelargonium sp. were sampled from paired plants twice throughout the year from the Ornamental Plant Germplasm Center. Their tissue was analyzed for essential macro- and micronutrients using ICP-OES. Generally, macronutrients varied by a factor of 3–5, whereas micronutrients varied by up to 100-fold. The micronutrient boron was a notable exception with variation across the samples of only about a factor of 5. With this information, attempts will be made to correlate tissue nutrient concentrations with genetic source (cultivars and breeding lines) and environmental conditions from the origin of the different Pelargonium species from South Africa. This work illustrates the challenges in associating specific sufficiency or deficiency values for nutrient concentrations in tissue of plants based on only a few cultivars, species, or locations.