Rosebay Willowherb : Chamerion angustifolium
Plant : Flowering towards the end of the season, it is a good source of pollen and nectar for colonies raising its winter workers and collecting winter stores. Rosebay willowherb produces tall stems, up to 1.5 m high. Bright pink flowers grow horizontally, in a spiral formation on the top part of the stem, while the rest of the stem has 10 cm leaves arranged in a similar spiral arrangement. Its habitat includes hedgerows, margins of woodland and common. It is particularly quick to establish in fire damaged areas of woodland or disturbed wasteland.
Flower : Rosebay willowherb flowers between July and September. Each flower is pink, with 4 petals, 8 stamens and an inferior ovary.
Pollen : The pollen load of rosebay willowherb is dark blue. The grain is round, although the pores give it a triangular appearance. It is approximately 75 um across. There are three pore type apertures. The surface is smooth and the exine is thin.
Rex Sawyer’s book, Pollen Identification for beekeepers is really helpful for understanding the features of pollen. In Bob Maurer’s book, Practical Microscopy for Beekeepers, he shows some simple techniques for making up pollen slides. Click here to return to plants for bees index.