Basic Landscape Design Principles
Invasive Species/Noxious Weed Status Update 2018 Northern Green Backyard Campfire Session 11:20-11:50 a.m., Wednesday, 1/4/2018 James B. Calkins, Ph.D. / Regulatory Affairs Manager
Amur Maple
Cutleaf Teasel
Amur Honeysuckle
Regulatory Authorities for Invasive Plants In Minnesota, terrestrial invasive plant species are regulated under the Minnesota Noxious Weed Law by the Minnesota Department of Agriculture (MDA) while aquatic invasive plant species are typically regulated by the Department of Natural Resources (DNR). Although the nursery and landscape industry is sometimes involved with aquatic plants, the regulation of terrestrial plants is most likely to impact the green industry. The MDA Noxious Weed Advisory Committee (NWAC), which includes MNLA representation, is the entity responsible for completing risk assessments for potential noxious weeds and making noxious weed listing recommendations to the Commissioner of Agriculture. In an attempt to avoid having a noxious weed list that was constantly changing on an annual basis, changes to the list are implemented on a 3-year cycle. Recent activities related to the regulation of invasive species/noxious weeds in /Minnesota are summarized below. Risk Assessments Completed for 21 New Species in 2014 and 2015 with the following recommendations:
No Regulatory Action / Do Not List (8 species) – Japanese hedge parsley (Torilis japonica), burnet saxifrage (Pimpinella saxifraga), purple starthistle (Centaurea calcitrapa), Iberian starthistle (Centaurea iberica), squarrose starthistle (Centaurea virgata), bird’s-foot trefoil (Lotus corniculatus), cow vetch (Vicia cracca), and hairy vetch (Vicia villosa).
List as a Restricted Noxious Weed (9 species; illegal to import, sell, plant, or transport, but existing plants and populations need not be controlled or eliminated.) – Bell’s honeysuckle (Lonicera x bella; L. morrowii x L. tatarica), Morrow’s honeysuckle (Lonicera morrowii), Tartarian/Tatarian honeysuckle (Lonicera tatarica), Amur honeysuckle (Lonicera maackii), tree of heaven (Ailanthus altissima), porcelain berry (Ampelopsis brevipendunculata), Queen Anne’s lace/Wild Carrot (Daucus carota), crown vetch (Securigera varia; formerly Coronilla varia), and black locust (Robinia pseudoacacia).
List as a Prohibited/Control Noxious Weed (1 species; illegal to import, sell, plant, or transport and spread by vegetative and sexual means (seed) must be prevented) – common barberry (Berberis vulgaris); this species has been regulated at the federal level for decades based on its role as the alternate host of black stem rust of wheat.
List as a Prohibited/Eradicate Noxious Weed (2 species; must be eradicated (both the above and below ground parts), illegal to import, sell, plant or transport, and measures must be taken to prevent introduction into Minnesota – Russian knapweed (Rhaponticum repens; synonyms Acroptilon repens and Centaurea repens) and diffuse knapweed (Centaurea diffusa).
List as a Specially Regulated Plant (1 species; allowed, but regulated based on a species-specific management plan) – Amur maple (Acer ginnala); in this case, Amur maple may only be planted in areas where the seedlings will be controlled by mowing or other regularly-conducted cultural
practices and should not be planted within 100 yards of natural areas; subsequent discussions have questioned whether this management strategy should be modified to require the removal of existing Amur maples that do not meet this this distance requirement, but no formal recommendation has been made at this time. No New Risk Assessments in 2016; Triennial Review of Species Currently Listed as Noxious Weeds In 2016, the NWAC determined that 12 species on the Minnesota Noxious Weed List required a formal review including an update of the risk assessments and resulting in the following recommendations: Oriental Bittersweet (Celastrus orbiculatus) – Prohibited/Eradicate (unchanged) Japanese Hops (Humulus japonicus) – Prohibited/Eradicate (unchanged) Common Teasel (Dipsacus fullonum) – Prohibited/Eradicate (unchanged) Cutleaf Teasel (Dipsacus laciniatus) – Prohibited/Eradicate (unchanged) Wild Parsnip (Pastinaca sativa) – Prohibited/Control (unchanged) Narrowleaf Bittercress (Cardamine impatiens) – Prohibited/Control (unchanged) Common Buckthorn (Rhamnus cathartica) – Restricted (unchanged) Glossy Buckthorn (Frangula alnus; formerly Rhamnus frangula) – Restricted (unchanged) Non-Native (European) Common Reed (Phragmites australis) – Prohibited/Control (was Restricted) Japanese Knotweed (Polygonum cuspidatum) – Specially Regulated (unchanged; review extended) Giant Knotweed (Polygonum sachalinensis) – Specially Regulated (unchanged; review extended) Bohemian Knotweed (Polygonum × bohemicum; P. cuspidatum × P. sachalinensis) – not currently listed In early 2017, with one exception, the Commissioner of Agriculture accepted all of the NWAC’s recommendations submitted in the fall of 2016 (2014-2016 species reviews and recommendations) and the Minnesota Noxious weed List was updated as a result of these designations. The exception was the recommendation to change the listing of non-native (European) common reed (Phragmites australis) from Restricted to Prohibited/Control which was rejected in response to concerns expressed by the MN DNR. Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC; University of Minnesota) The MITPPC was created by the Minnesota Legislature in 2014 "to prevent and minimize the threats posed by terrestrial invasive plants, other weeds, pathogens, and pests in order to protect the state's prairies, forests, wetlands, and agricultural resources." The MITPPC has subsequently developed prioritized lists of the top invasive insects (40 species), plants/weeds (45 species), and pathogens (39 species) in Minnesota (124 species total) http://www.mitppc.umn.edu/sites/g/files/pua746/f/media/white_paper_final_11-1416.pdf. The top 15 species from each list (insects, plants/weeds, and pathogens) have subsequently been chosen as the focus of the Center's research efforts and requests for research proposals. These lists will be reviewed and updated on a regular basis. According to the current MITPPC rankings, the top 15 invasive plant/weed species include 1) spotted knapweed (Centaurea maculosa), 2) common tansy (Tanacetum vulgare), 3) Morrow's honeysuckle (Lonicera morrowii), 4) glossy/alder buckthorn (Frangula alnus; formerly Rhamnus frangula), 5) European common reed (Phragmites australis subsp. australis Haplotype M), 6) Tatarian/Tartarian honeysuckle (Lonicera tatarica), 7) Common/European buckthorn (Rhamnus cathartica), 8) Canada thistle (Cirsium arvense), 9) leafy spurge (Euphorbia esula), 10) wild parsnip (Pastinaca sativa), 11) Japanese knotweed (Polygonum cuspidatum), 12) reed canarygrass (Phalaris arundinacea), 13) spiny plumeless thistle (Carduus acanthoides), 14) crown vetch (Securigera varia; formerly Coronilla varia), and 15) garlic mustard (Alliaria petiolata). All of the woody species in this group (four species; Numbers 3, 4, 6, & 7) and two of the herbaceous species (Numbers 11 & 14) were formerly nursery and landscape species that are now variously regulated under the Minnesota Noxious Weed Law and one herbaceous species is still grown and planted in landscapes (Number 12). Of the remaining 30 species on the MITPPC invasive plant/weed list, five are of
interest to the nursery and landscape industry including four woody species – Japanese barberry (Berberis thunbergii), Norway maple (Acer platanoides), Siberian peashrub (Caragana arborescens), and winged euonymus/burning bush (Euonymus alatus) – and one herbaceous species – giant knotweed (Polygonum sachalinensis). Of these, Japanese barberry (seedy varieties became Restricted Noxious Weeds in Minnesota earlier this week; January 1, 2018) and giant knotweed (together with Japanese knotweed in the top 15) are currently regulated as Specially Regulated Plants in Minnesota. The three remaining species (Norway maple, Siberian peashrub, and winged euonymus/burning bush) are not yet regulated in Minnesota, but are currently under review by the NWAC Listing Subcommittee (see below). Palmer Amaranth Discovered in West Central Minnesota in 2016 and New Areas in 2017 Palmer amaranth (Amaranthus palmeri) was discovered in Yellow Medicine and Lyon Counties in September, 2016, and additional infestations have been identified in Douglas and Todd Counties in 2017. The Minnesota Department of Agriculture is coordinating efforts to eradicate these infestations in an attempt to prevent the spread of this serious weed to new areas. Palmer amaranth was designated as a Prohibited/Eradicate Noxious Weed in Minnesota in 2014. Thus far, all of the known infestations in Minnesota are in conservation plantings rather than crop production areas and are believed to have originated from a single seed source. MNLA members should be aware of this important weed and help prevent its spread through contaminated seed and other means. Risk Assessments Completed for 6 New Species in 2017 with the following recommendations: No Regulatory Action / Do Not List (5 species) – hoary alyssum (Berterola incana), Mexican fireweed/kochia (Bassia scoparia; formerly Kochia scoparia), white sweetclover (Melilotus alba), yellow sweetclover (Melilotus officinalis), and reed canarygrass (Phalaris arundinacea).
List as a Prohibited/Eradicate Noxious Weed (1 species; must be eradicated (both the above and below ground parts), illegal to import, sell, plant or transport, and measures must be taken to prevent introduction into Minnesota – poison hemlock (Conium maculatum).
These recommendations are now in the hands of the Commissioner of Agriculture and final decisions are expected in early 2018. If approved, poison hemlock would be added to the Minnesota Noxious Weed List as an emergency listing in 2018. In addition, a risk assessment was initiated for winged burning bush/euonymus (Euonymus alatus) in 2017 and work on updating the risk assessments for the knotweeds – Japanese knotweed (Polygonum cuspidatum; currently listed as a Specially Regulated Plant), giant knotweed (Polygonum sachalinense; currently listed as a Specially Regulated Plant), and Bohemian knotweed (Polygonum x bohemicum; a naturally-occurring hybrid between Polygonum cuspidatum and Polygonum sachalinense; not previously reviewed) continued in 2017. The outcome of all of these assessments, and especially for winged burning bush/euonymus, will impact the nursery and landscape industry and work on these risk assessments will continue in 2018. Risk Assessments Scheduled for 7 New Species in 2018: In addition to the ongoing reviews of winged burning bush/euonymus and the three knotweeds, seven new species will be reviewed next year including Norway maple (Acer platanoides), European alder (Alnus glutinosa), Siberian peashrub (Caragana arborescens), blue mustard (Chorispora tenella), orange hawkweed (Hieracium aurantiacum), meadow hawkweed (Hieracium caespitosum), and Japanese honeysuckle (Lonicera japonica). Obviously, several of these species, and especially Norway maple, are important to the nursery and landscape industry. The MDA, in partnership with the MNLA has surveyed nursery certificate holders and the MNLA membership to gather information about the potential impacts to the nursery and landscape industry if these species were listed as noxious weeds in the State of Minnesota and the regulation of invasive species in Minnesota.
The Minnesota Noxious Weed List is available on the Minnesota Department of Agriculture (MDA) website at https://www.mda.state.mn.us/plants/pestmanagement/weedcontrol/noxiouslist.aspx. Input from MNLA members on the listing and regulation of invasive species/noxious weeds is always welcome and encouraged. If you have questions, concerns, or comments about the regulation of invasive plant species/noxious weeds in Minnesota, contact Jim Calkins at: [email protected]; 952-935-0682
Amur Maple
Cutleaf Teasel
Amur Honeysuckle
Regulatory Authorities for Invasive Plants In Minnesota, terrestrial invasive plant species are regulated under the Minnesota Noxious Weed Law by the Minnesota Department of Agriculture (MDA) while aquatic invasive plant species are typically regulated by the Department of Natural Resources (DNR). Although the nursery and landscape industry is sometimes involved with aquatic plants, the regulation of terrestrial plants is most likely to impact the green industry. The MDA Noxious Weed Advisory Committee (NWAC), which includes MNLA representation, is the entity responsible for completing risk assessments for potential noxious weeds and making noxious weed listing recommendations to the Commissioner of Agriculture. In an attempt to avoid having a noxious weed list that was constantly changing on an annual basis, changes to the list are implemented on a 3-year cycle. Recent activities related to the regulation of invasive species/noxious weeds in /Minnesota are summarized below. Risk Assessments Completed for 21 New Species in 2014 and 2015 with the following recommendations:
No Regulatory Action / Do Not List (8 species) – Japanese hedge parsley (Torilis japonica), burnet saxifrage (Pimpinella saxifraga), purple starthistle (Centaurea calcitrapa), Iberian starthistle (Centaurea iberica), squarrose starthistle (Centaurea virgata), bird’s-foot trefoil (Lotus corniculatus), cow vetch (Vicia cracca), and hairy vetch (Vicia villosa).
List as a Restricted Noxious Weed (9 species; illegal to import, sell, plant, or transport, but existing plants and populations need not be controlled or eliminated.) – Bell’s honeysuckle (Lonicera x bella; L. morrowii x L. tatarica), Morrow’s honeysuckle (Lonicera morrowii), Tartarian/Tatarian honeysuckle (Lonicera tatarica), Amur honeysuckle (Lonicera maackii), tree of heaven (Ailanthus altissima), porcelain berry (Ampelopsis brevipendunculata), Queen Anne’s lace/Wild Carrot (Daucus carota), crown vetch (Securigera varia; formerly Coronilla varia), and black locust (Robinia pseudoacacia).
List as a Prohibited/Control Noxious Weed (1 species; illegal to import, sell, plant, or transport and spread by vegetative and sexual means (seed) must be prevented) – common barberry (Berberis vulgaris); this species has been regulated at the federal level for decades based on its role as the alternate host of black stem rust of wheat.
List as a Prohibited/Eradicate Noxious Weed (2 species; must be eradicated (both the above and below ground parts), illegal to import, sell, plant or transport, and measures must be taken to prevent introduction into Minnesota – Russian knapweed (Rhaponticum repens; synonyms Acroptilon repens and Centaurea repens) and diffuse knapweed (Centaurea diffusa).
List as a Specially Regulated Plant (1 species; allowed, but regulated based on a species-specific management plan) – Amur maple (Acer ginnala); in this case, Amur maple may only be planted in areas where the seedlings will be controlled by mowing or other regularly-conducted cultural
practices and should not be planted within 100 yards of natural areas; subsequent discussions have questioned whether this management strategy should be modified to require the removal of existing Amur maples that do not meet this this distance requirement, but no formal recommendation has been made at this time. No New Risk Assessments in 2016; Triennial Review of Species Currently Listed as Noxious Weeds In 2016, the NWAC determined that 12 species on the Minnesota Noxious Weed List required a formal review including an update of the risk assessments and resulting in the following recommendations: Oriental Bittersweet (Celastrus orbiculatus) – Prohibited/Eradicate (unchanged) Japanese Hops (Humulus japonicus) – Prohibited/Eradicate (unchanged) Common Teasel (Dipsacus fullonum) – Prohibited/Eradicate (unchanged) Cutleaf Teasel (Dipsacus laciniatus) – Prohibited/Eradicate (unchanged) Wild Parsnip (Pastinaca sativa) – Prohibited/Control (unchanged) Narrowleaf Bittercress (Cardamine impatiens) – Prohibited/Control (unchanged) Common Buckthorn (Rhamnus cathartica) – Restricted (unchanged) Glossy Buckthorn (Frangula alnus; formerly Rhamnus frangula) – Restricted (unchanged) Non-Native (European) Common Reed (Phragmites australis) – Prohibited/Control (was Restricted) Japanese Knotweed (Polygonum cuspidatum) – Specially Regulated (unchanged; review extended) Giant Knotweed (Polygonum sachalinensis) – Specially Regulated (unchanged; review extended) Bohemian Knotweed (Polygonum × bohemicum; P. cuspidatum × P. sachalinensis) – not currently listed In early 2017, with one exception, the Commissioner of Agriculture accepted all of the NWAC’s recommendations submitted in the fall of 2016 (2014-2016 species reviews and recommendations) and the Minnesota Noxious weed List was updated as a result of these designations. The exception was the recommendation to change the listing of non-native (European) common reed (Phragmites australis) from Restricted to Prohibited/Control which was rejected in response to concerns expressed by the MN DNR. Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC; University of Minnesota) The MITPPC was created by the Minnesota Legislature in 2014 "to prevent and minimize the threats posed by terrestrial invasive plants, other weeds, pathogens, and pests in order to protect the state's prairies, forests, wetlands, and agricultural resources." The MITPPC has subsequently developed prioritized lists of the top invasive insects (40 species), plants/weeds (45 species), and pathogens (39 species) in Minnesota (124 species total) http://www.mitppc.umn.edu/sites/g/files/pua746/f/media/white_paper_final_11-1416.pdf. The top 15 species from each list (insects, plants/weeds, and pathogens) have subsequently been chosen as the focus of the Center's research efforts and requests for research proposals. These lists will be reviewed and updated on a regular basis. According to the current MITPPC rankings, the top 15 invasive plant/weed species include 1) spotted knapweed (Centaurea maculosa), 2) common tansy (Tanacetum vulgare), 3) Morrow's honeysuckle (Lonicera morrowii), 4) glossy/alder buckthorn (Frangula alnus; formerly Rhamnus frangula), 5) European common reed (Phragmites australis subsp. australis Haplotype M), 6) Tatarian/Tartarian honeysuckle (Lonicera tatarica), 7) Common/European buckthorn (Rhamnus cathartica), 8) Canada thistle (Cirsium arvense), 9) leafy spurge (Euphorbia esula), 10) wild parsnip (Pastinaca sativa), 11) Japanese knotweed (Polygonum cuspidatum), 12) reed canarygrass (Phalaris arundinacea), 13) spiny plumeless thistle (Carduus acanthoides), 14) crown vetch (Securigera varia; formerly Coronilla varia), and 15) garlic mustard (Alliaria petiolata). All of the woody species in this group (four species; Numbers 3, 4, 6, & 7) and two of the herbaceous species (Numbers 11 & 14) were formerly nursery and landscape species that are now variously regulated under the Minnesota Noxious Weed Law and one herbaceous species is still grown and planted in landscapes (Number 12). Of the remaining 30 species on the MITPPC invasive plant/weed list, five are of
interest to the nursery and landscape industry including four woody species – Japanese barberry (Berberis thunbergii), Norway maple (Acer platanoides), Siberian peashrub (Caragana arborescens), and winged euonymus/burning bush (Euonymus alatus) – and one herbaceous species – giant knotweed (Polygonum sachalinensis). Of these, Japanese barberry (seedy varieties became Restricted Noxious Weeds in Minnesota earlier this week; January 1, 2018) and giant knotweed (together with Japanese knotweed in the top 15) are currently regulated as Specially Regulated Plants in Minnesota. The three remaining species (Norway maple, Siberian peashrub, and winged euonymus/burning bush) are not yet regulated in Minnesota, but are currently under review by the NWAC Listing Subcommittee (see below). Palmer Amaranth Discovered in West Central Minnesota in 2016 and New Areas in 2017 Palmer amaranth (Amaranthus palmeri) was discovered in Yellow Medicine and Lyon Counties in September, 2016, and additional infestations have been identified in Douglas and Todd Counties in 2017. The Minnesota Department of Agriculture is coordinating efforts to eradicate these infestations in an attempt to prevent the spread of this serious weed to new areas. Palmer amaranth was designated as a Prohibited/Eradicate Noxious Weed in Minnesota in 2014. Thus far, all of the known infestations in Minnesota are in conservation plantings rather than crop production areas and are believed to have originated from a single seed source. MNLA members should be aware of this important weed and help prevent its spread through contaminated seed and other means. Risk Assessments Completed for 6 New Species in 2017 with the following recommendations: No Regulatory Action / Do Not List (5 species) – hoary alyssum (Berterola incana), Mexican fireweed/kochia (Bassia scoparia; formerly Kochia scoparia), white sweetclover (Melilotus alba), yellow sweetclover (Melilotus officinalis), and reed canarygrass (Phalaris arundinacea).
List as a Prohibited/Eradicate Noxious Weed (1 species; must be eradicated (both the above and below ground parts), illegal to import, sell, plant or transport, and measures must be taken to prevent introduction into Minnesota – poison hemlock (Conium maculatum).
These recommendations are now in the hands of the Commissioner of Agriculture and final decisions are expected in early 2018. If approved, poison hemlock would be added to the Minnesota Noxious Weed List as an emergency listing in 2018. In addition, a risk assessment was initiated for winged burning bush/euonymus (Euonymus alatus) in 2017 and work on updating the risk assessments for the knotweeds – Japanese knotweed (Polygonum cuspidatum; currently listed as a Specially Regulated Plant), giant knotweed (Polygonum sachalinense; currently listed as a Specially Regulated Plant), and Bohemian knotweed (Polygonum x bohemicum; a naturally-occurring hybrid between Polygonum cuspidatum and Polygonum sachalinense; not previously reviewed) continued in 2017. The outcome of all of these assessments, and especially for winged burning bush/euonymus, will impact the nursery and landscape industry and work on these risk assessments will continue in 2018. Risk Assessments Scheduled for 7 New Species in 2018: In addition to the ongoing reviews of winged burning bush/euonymus and the three knotweeds, seven new species will be reviewed next year including Norway maple (Acer platanoides), European alder (Alnus glutinosa), Siberian peashrub (Caragana arborescens), blue mustard (Chorispora tenella), orange hawkweed (Hieracium aurantiacum), meadow hawkweed (Hieracium caespitosum), and Japanese honeysuckle (Lonicera japonica). Obviously, several of these species, and especially Norway maple, are important to the nursery and landscape industry. The MDA, in partnership with the MNLA has surveyed nursery certificate holders and the MNLA membership to gather information about the potential impacts to the nursery and landscape industry if these species were listed as noxious weeds in the State of Minnesota and the regulation of invasive species in Minnesota.
The Minnesota Noxious Weed List is available on the Minnesota Department of Agriculture (MDA) website at https://www.mda.state.mn.us/plants/pestmanagement/weedcontrol/noxiouslist.aspx. Input from MNLA members on the listing and regulation of invasive species/noxious weeds is always welcome and encouraged. If you have questions, concerns, or comments about the regulation of invasive plant species/noxious weeds in Minnesota, contact Jim Calkins at: [email protected]; 952-935-0682
