Allegheny River Headwaters Watershed Conservation Plan

Allegheny River Headwaters Conservation Plan
Chapter 4. Biological Resources
Russian olive, native to Eurasia, was introduced into the U.S. during the late 1800s, and is used as an
ornamental plant and in erosion control, wildlife cover, landscaping, and mining reclamation.
Both species aggressively overtake native species. Their nitrogen fixing capabilities adversely affects
the nitrogen cycle of the native communities. It creates heavy shade, suppressing plants that require direct
sunlight for growth.
Due to its rapid growth rate, controlling populations of autumn olive and Russian olive can be
challenging. Avoid cutting and mowing areas that contain populations of autumn olive and Russian olive;
these activities cause vigorous resprouting, even when frequently cut, increasing the species’ ability to
spread. It can be hand pulled, and the use of herbicides following cutting during the growing season
seems to be effective. It may take multiple treatments before eradication of the species is successful
(Invasive Plant Species Assessment Working Group (IPSAWG), 2006).
Autumn olive and Russian olive are established in Potter County. Although not detected in McKean
County as of 2010, the area is at risk with the potential for establishment. Extra caution and surveillance
are needed in order to stop the spread of these species and eradicate them before a prolific population is
established.
Exotic Bush Honeysuckles
Amur, Standish, Tartarian, and Morrow honeysuckles are often grouped together and termed exotic
bush honeysuckles. Native to eastern Asia, they were introduced into the U.S. as early as 1752 for
wildlife cover, erosion control, and as ornamental plants.
These species of honeysuckle are approximately 6–15 feet high, and grow as a deciduous shrub. The
flower color varies from cream to pink or crimson. They are shade intolerant and mostly located along
forest edges, abandoned fields, pastures, roadsides, and other open upland areas.
Amur and Standish honeysuckles have established in Potter County, while Morrow and Tartarian
honeysuckles have established in McKean and Potter counties. Morrow honeysuckle is capable of
invading bogs, fens, lakeshores, sand plains, and other uncommon habitats.
Honeysuckles rapidly invade areas, overtaking a site by forming a dense shrub layer that crowds and
shades-out native plant species. It alters habitats by decreasing light availability, depleting soil moisture
and nutrients, and possibly releasing toxic chemicals that prevent other plant species from growing in the
vicinity. They compete for pollinators, reducing seed sets for native species.
Prevention is the easiest control method available. Once the species are established, a variety of
removal methods could be implemented; however, any control method should be initiated prior to seed
dispersal. Manually pulling the plants can be effective but is very labor intensive especially on large
infestations and requires several years to exhaust the seed bank. Chemical treatment using herbicides is
also effective, and becomes even more effective when combined with manual removal techniques. Large
infestations in open fields can be controlled with prescribed burning.
Japanese honeysuckle
Native to Japan and Korea, Japanese honeysuckle was introduced in the U.S. during the mid 1800s
for erosion control, wildlife habitat, and as an ornamental plant. Its highly fragrant flowers provide a tiny
drop of honey-flavored nectar. Japanese honeysuckle is a perennial vine that climbs and twists over
obstacles, competing for light. Flowers are white to pink, turn yellow with age, and bloom from late April
through July. Small black fruits containing two to three oval to oblong dark brown seeds are produced in
autumn.
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