NOVEMBER 2021 INVASIVE PLANT OF THE MONTH
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Multiflora Rose (Rosa multiflora)
Multiflora rose (Rosa multiflora) is a multi-stemmed, thorny, sometimes climbing, perennial shrub that grows up to 15 feet tall. Originating in eastern Asian, it was introduced to the eastern United States as rootstock for ornamental roses. Beginning in the 1930s, the U.S. Soil Conservation Service promoted its use in erosion control and as “living fences” to confine livestock. State conservation departments recommended multiflora rose as food and cover for wildlife. However, its tenacious growth habit was eventually recognized as it forms impenetrable thickets in pastures, fields, and forest edges, disrupting cattle grazing and degrading native ecosystems. In Indiana, it is illegal to move, plant, or distribute multiflora rose without a permit, according to DNR DEPP Admin code 312 IAC 18-3-13. It is designated a noxious weed in several states including Iowa, Ohio, New Jersey, Pennsylvania, and West Virginia.
IDENTIFICATION & BIOLOGY: Stems: Stems are green to red arching canes which are round in cross section and have stiff, curved thorns. Leaves: Leaves are pinnately compound with 7-9 leaflets. Leaflets are oblong, 1-1.5 inches long and have serrated edges. The fringed petioles distinguish it from most other native rose species. Flowers: Small, fragrant, white to pinkish, 5-petaled flowers occur abundantly in clusters on the plant in the spring. Fruits: Fruit are small, red rose hips that remain on the plant throughout the winter. Seeds are dispersed by birds and other wildlife that eat the fruits.
LOOK-A-LIKES: Pasture rose (Rosa carolina); swamp rose (Rosa palustris); Allegheny blackberry (Rubus allegheniensis); flowering raspberry (Rubus odoratus). Only multiflora rose has the combination of upright arching stems and fringed stipules, and produces flowers that are smaller in size, but with greater abundance, than the native roses.
HABITAT & DISTRIBUTION: Multiflora rose has a wide tolerance for various soil, moisture, and light conditions. It can grow in dense woods, prairies, along stream banks and roadsides and in open fields and pastures. It has been reported in every county of Indiana and is now found throughout most of the eastern half of the United States and a few western states.
ECOLOGICAL THREAT: Multiflora rose forms impenetrable thickets in pastures, fields, and forest edges. It restricts human, livestock, and wildlife movement and displaces native vegetation. Dense thickets of multiflora rose exclude most native shrubs and herbs from establishing and may be detrimental to nesting of native birds. Multiflora rose grows aggressively and produces large numbers of fruits that are eaten and dispersed by a variety of birds.
CONTROL: Like other invasive species, a combination of control tactics is necessary to manage multiflora rose. The most effective control is to prevent it from becoming established. Plants should be removed as soon as possible when they are found. Small plants and seedlings can be hand-pulled with protective gloves, especially when the soil is moist. However, root fragments left in the soil may resprout. Mechanical and chemical methods are currently the most widely used methods for managing multiflora rose. Application of systemic herbicides (e.g., glyphosate) on freshly cut stumps or to regrowth may be the most effective methods, especially if conducted late in the growing season. Foliar application of herbicide can also be effective, but care must be taken if there are desirable species in the area. Cutting without the use of herbicide can limit the spread but will not eradicate it. In this case, stems should be cut at least once per growing season as close to ground level as possible.
IMPORTANT: The pesticide label is the law! When using any chemical control, always read the entire pesticide label carefully, follow all mixing and application instructions and use all personal protective gear and clothing specified. Contact the Office of Indiana State Chemist (OISC) for additional pesticide use requirements, restrictions or recommendations.
REFERENCES & OTHER RESOURCES:
https://www.eddmaps.org/species/subject.cfm?sub=3071
https://www.inaturalist.org/taxa/78882-Rosa-multiflora
https://www.illinoiswildflowers.info/weeds/plants/multiflora_rose.htm
https://www.misin.msu.edu/facts/detail/?project=misin&id=15&cname=Multiflora+rose
https://www.invasive.org/browse/subinfo.cfm?sub=3071
https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs144p2_014999.pdf
http://www.sicim.info/news/2020/4/18/tprandguide
https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_018028.pdf
https://ourwaterways.org/multiflora-rose/
https://www.in.gov/dnr/entomology/regulatory-information/
LOOK-A-LIKE REFERENCES:
https://www.illinoiswildflowers.info/weeds/plants/multiflora_rose.htm
https://www.invasive.org/alien/pubs/midatlantic/romu.htm
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