As I walked the trails at Griggstown Grasslands on Saturday, I became aware of a lot of bees buzzing around one particular shrub. When I looked more closely at what was drawing their attention, I noticed it was an Autumn Olive in full bloom. The small white flowers had a strong fragrance, almost overwhelming at close range. The Honey Bees visiting the shrub made a constant hum of activity, more so than around nearby blooming trees of other species.
Autumn Olive can be recognized by its long, thin leaves that are dark green on one side and silvery on the other. In the fall, these shrubs bear red berries that are very attractive to wildlife and edible for humans as well. The leaf and berry coloration help distinguish it from the very similar Russian Olive, as explained here.
That attractiveness to wildlife is one of the factors that makes this species so invasive since it is easier for a plant to reproduce if it has insects eager to pollinate it and birds ready to spread its seeds. Another factor is that it is able to fix nitrogen with its roots. This allows it to spread readily in poor soils where other plants struggle to survive. Aside from that, they are also drought resistant and difficult to kill by cutting or fire. Autumn Olive may be an example of an introduction succeeding too well. These shrubs were planted widely in Appalachia to revegetate former strip mines and other disturbed areas because of their tolerance for poor soils. Since then the shrub has spread rapidly and become a seemingly permanent fixture of the landscape.