Species of the Month, October 2021: Norfolk Road Asters

by Mary Gartshore

A few years back a photographer called me and asked: “Are asters flowering yet down there in Norfolk?” Norfolk is blessed with many species of asters but I will focus on those visible on roadsides.

Asters include open country species like New England Aster (dark purple), Frost Aster (tall, small white), Heath Aster (short, dense white, tiny leaves), Purple-stemmed Aster (bluish-white in wet areas, fuzzy stem), Lance-leaved Aster (moist areas, bluish-white, naked stem), Sky Blue Aster (pale blue, rough leaves), Smooth Aster (pale blue plastic-like leaves), Arrow-leaved Aster (whitish with pink, shaped like a Christmas tree). Shady roadsides may have Heart-leaved Aster (dense pale blue and heart-shaped leaves).

All the asters we see on roadsides, hedgerows, and other open areas are native and support wild pollinators during September and October.  They are not weedy and are easily killed by tilling, mowing, and herbicides.  They can prevent troublesome weeds from establishing.

Asters are the ‘last call’ in Canada for Monarch butterflies migrating for the winter to the mountains of Mexico.   Insects that nectar on asters include beneficial, pollinators, predators and parasites.  Measuring the effectiveness of pollination can be quite difficult. Purple-stemmed Aster is prized in pollination research as the seed set reflects the amount of pollinator visits – a useful measure of this ecological service.