Presently in the valleys of the Lower Susquehanna River Watershed, you’re sure to see a gorgeous nightmare, showy stands of flowering Callery Pear (Pyrus calleryana). Invasive groves like this one quickly dominate successional habitat and often create monocultures, often excluding native pioneer trees like Eastern Red Cedar and several species of deciduous hardwood. The void beneath the pear trees in this photograph shows how deer browsing can intensify the damage, preventing other plant species from becoming established in the understory. In autumn, crimson foliage again makes these non-native trees a standout in the landscape. The red leaves attract birds including American Robins and Cedar Waxwings to the abundant berries, but European Starlings usually get to them first. Planted specimens of ornamental Callery Pears began producing fertile seeds when multiple varieties became available in addition to the self-sterile “Bradford Pears” that were planted widely during the last decades of the twentieth century. Cross-pollination between varieties produces the fertile seeds that are distributed by starlings and other birds as they digest the fruit.
