Evaluation of Selected Ornamental Asteraceae as a Pollen Source for Urban Bees

Offering more floral resources for urban bees can be achieved by growing ornamental bee plants. The aim of the present study was to evaluate selected Asteraceae ( ‘Persimmon Beauty’ and ‘Santana’, , , , , , and ) as pollen sources for pollinators. Under urban conditions in Lublin, SE Poland, the investigated plants flowered from late June to the end of October. The mass of pollen produced in florets and capitula was found to be species-related. The highest pollen amounts per 10 florets (10.1 mg) as well as per capitulum (249.7 mg) were found for . The mass of pollen yielded by a single plant depended on both the pollen mass delivered per disk florets and the proportion of disk florets in capitulum, and the flowering abundance of the plants. A single plant of and a single plant of each produced the largest pollen mass. Mean pollen yield per 1m of a plot ranged from 6.2 g ( ) to 60.7 g ). Pollen grains are tricolporate, with echinate exine, medium or small in size. They can be categorised as oblatespherical, spherical, and prolatespherical. The principal visitors to , , and were honey bees, whereas bumble bees dominated on and . A magnet plant for butterflies was . Among the investigated species, , , and were found to be the most valuable sources of pollen flow for managed and wild bees.