Nasturtiums (Tropaeolum majus) are easy-to-grow annuals with bright vibrant flowers. There are many different cultivars available to gardeners, ranging in colour from pale yellow, through orange and red, to deep burgundy. Flowers produce both nectar and pollen, and are well visited by bumblebees.
In 2016, with the help of a Coventry University student intern Giri Kiritharan and undergraduate Becky Ashworth, we grew and compared seven nasturtium cultivars: Black Velvet, Cherry Rose Jewel, Empress of India, Gleam, Ladybird, Vesuvius, and Wina. We carried out regular monitoring, counting and identifying visiting bumblebees, and quantifying nectar and pollen production.
We are currently analysing the data to determine whether bumblebees demonstrated preferences for any particular cultivars, and whether the amount of nectar and pollen produced varied between the cultivars. Results will be shared here and on our blog shortly.