Autumn olive is a woody small tree known for invading open prairies, disturbed areas, and woodland edges. It houses nitrogen fixing bacteria on its roots, allowing for rapid growth and colonization, while altering soil conditions.
- typically grows up to 15 feet high and 20 feet wide, branching from multiple stems
- alternate green leaves with a distinctly silvery underside and wavy margins
- stems have 1 inch thorns and new growth is reddish with distinct silvery speckles or scales
- flowers are cream colored with four petals and bloom around May, turning into yellow or red drupes later in the season
Another key identifying feature are the root nodules visible on plants when physically pulled from the ground. These nodules are bumpy and white, and house bacteria in the genus Frankia, allowing for nitrogen fixation.
For more information, visit Woody Invasives of the Great Lakes (WIGL) Collaborative and Midwest Invasive Species Information Network (MISIN).
KISMA Management Practices
Autumn olive is a prevalent invasive in downstate Michigan, and has a spotty distribution throughout the upper peninsula. Managing this species is similar to managing other woody invasives like buckthorn.
- using root wrenches or shovels to loosen root ball and remove as much of the root mass as possible
- hang pulled shrubs to dry or dispose of in a landfill or burn site if the shrub contains ripe berries
- if trees are too large for manual pulling, cutting at the stump can be effective as long as care is taken to cover the stump in thick plastic bags to prevent stump sprout regeneration
- small saplings are easiest to remove by hand before becoming well established
Note: Autumn olive can easily regrow from large amounts of root mass left in the ground, so care should be taken to remove as much of the underground portion as possible. Wearing protective gloves and sleeves is encouraged due to the thorny nature of this plant. Hanging or burning of the removed plant material is acceptable, however, care should be taken to remove all present fruits before transporting or hanging the pulled material.
Species such as beaked hazelnut (Corylus cornuta) and downy arrow-wood (Viburnum rafinesquianum) are native understory shrubs that inhabit forest edges similar to autumn olive. Red-osier dogwood (Cornus sericea) and highbush cranberry (Viburnum trilobum) are also good alternatives for replanting in wetland edges and more riparian areas.