Autumn olive, also called Japanese Silverberry is an invasive plant (scientific name: Elaeagnus umbellata Thunb). It has become problematic across the central and eastern United States, especially southeastern PA. It is easy to recognize from the silvery undersides of its leaves and its grayish-green upper surfaces. Birds eat its red berries thus spreading the species by seed through their feces. Autumn olive is a deciduous shrub which grows to 20 feet in height. Small, yellowish flowers are abundant and occur in clusters near the stems in May to June. Fruits are red, juicy, and edible. They ripen from September to November.
Autumn olive invades old fields, woodland edges, and other disturbed areas. It can form a dense shrub layer which displaces native species and closes open areas. Autumn olive is native to China and Japan and was introduced into North America in 1830 and was formerly heavily promoted as a conservation planting. In fact, there are still state tree nurseries growing this plant; which even included Ohio until recently.
These are difficult plants to eradicate. Smaller plants should be pulled. Larger plants should be killed by cutting the woody stems close to the ground and applying concentrated herbicide to the cut surfaces. Repeat cutting alone will not destroy the plant. If you pull or cut this plant do not chip it and then use the chips. This will most certainly lead to additional plants sprouting.
Autumn olive berries though are crammed with nutritional value. Its brilliant-red berries are edible and can be turned into jams. The red berries of autumn olive have a high carotenoid content and particularly high levels of lycopene (30-70 mg/100g). Ounce for ounce, the typical autumn olive berry is up to 17 times higher in lycopene than the typical raw tomato. Lycopene has powerful antioxidant properties and has generated widespread interest as a possible deterrent to heart disease and cancers of the prostate, cervix and gastrointestinal tract. The berries also contain high levels of vitamins A, C and E, and flavonoids and essential fatty acids.
Several counties in our area with some of the highest numbers of this invasive species in the state are: Philadelphia, Bucks, Montgomery, Northampton, Berks, Lehigh, Chester, Lancaster and Delaware.
Autumn olive can be found all around the Lehigh Valley including in Northampton County along the Monocacy Creek in Bethlehem and the Lehigh Towpath (D&L Trail), and in Lehigh County along the Lehigh Canal Towpath (D&L Trail), at the Pool Wildlife Sanctuary in Emmaus, the Burnside Plantation in Bethlehem and at the Jordan Creek Parkway in Whitehall and South Whitehall townships. The area with the highest concentration of the plant in the Lehigh Valley is at the Trexler Game Preserve in Schnecksville.