Post on 12-Jun-2020
A quick reference guide to
Invasive Plant Species
Acknowledgements
Technical input provided by:
• TheOntarioInvasivePlantCouncil• RoyalBotanicalGardens
Photosandillustrationsprovidedby:
• CreditValleyConservation• TheNatureConservancy-US• RoyalBotanicalGardens• TorontoandRegionConservation• OntarioFederationofAnglersandHunters
Text compiled and written by:
• CreditValleyConservation
Graphicdesignandproductionprovidedby:
• TorontoandRegionConservation
Coverphoto:garlicmustard(Alliaria petiolata)
Manitoba mapleAcer negundo
Norway mapleAcer platanoides
European or black alderAlnus glutinosa
European spindletree & winged euonymusEuonymus europaeus and E. alatus
non-native bush honeysucklesLonicera spp.
common & glossy buckthornRhamnus cathartica & R. frangula
dog-strangling vineCynanchum rossicum & C. nigrum
garlic mustardAlliaria petiolata
giant hogweedHeracleum mantegazzianum
Himalayan balsamImpatiens glandulifera
Japanese knotweedPolygonum cuspidatum
reed or giant manna grassGlyceria maxima
common reedPhragmites australis
goutweedAegopodium podagraria
English ivyHedera helix
periwinkleVinca minor
IntroductionSouthern Ontario’s native plants existed here for thousands of years prior to European settlement. This diverse group of plants evolved together with indigenous wildlife, adapting to local climate and soil conditions to create stable natural communities we call ecosystems.
By contrast, invasive plants come from outside this geographic area. When they are introduced, there is potential for them to establish themselves and disrupt established ecosystems forcing out native plants. Fewer native plants results in decreased biodiversity. This can mean less food and shelter for wildlife dependent on native plants. This results in a ripple effect that threatens whole ecosystems and has economic and social implications as well.
What makes a plant invasive?Not all introduced plants are invasive. Some, like the common dandelion, may be a nuisance, but do not pose a significant threat to native plants and their ecosystems. Others, including many common garden plants are benign and even beneficial. Invasive plants are a concern because they have “displacement capacity” meaning they form such dense colonies or compete so aggressively, that they force out native vegetation.
Invasive plants commonly have one or more of the following characteristics allowing them to out-compete native species:
• High annual seed production and quick establishment of dense colonies;
• Tolerance to a wide range of growing conditions;
• Ability to spread by underground roots and re-grow quickly when disturbed by pulling, cutting or fire;
• A lack of natural predators to keep their population under control in their new environment.
What can I do about invasive plants?• Learn to properly identify and manage invasive plants on your property. If you are unsure about identification, removal or control measures, contact the organizations listed below.• When selecting plants for your garden, purchase non-invasive or native plants from reputable suppliers. Native plants will provide a variety of benefits to the insects and wildlife that also depend on them. • Dispose of yard waste through your local municipality or in your backyard composter. Yard waste dumped in natural areas may contain invasive plant seeds.• Share this information with your neighbours, friends and family. The more people who know about the problem, the easier it will be to stop the introduction and spread of invasive species. • When walking or hiking in natural areas, remain on designated trails and keep pets on a leash to avoid disturbing natural vegetation or transferring invasive plants and their seeds to new areas. Always clean off your bike, hiking boots or clothes and brush your dog’s fur before leaving the natural area, to avoid accidentally spreading seeds. • Volunteers are sometimes needed to help with locating and controlling invasive species. For invasive plant management projects in your community contact the organizations listed below.
Getting Help:•Ontario Invasive Plant Council, www.ontarioinvasiveplants.ca• Stewardship Councils c/o Ontario Ministry of Natural Resources, www.mnr.gov.on.ca•Ontario Federation of Anglers and Hunters, www.ofah.org•The Invading Species Hotline, 1-800-563-7711 • Conservation Authorities, www.conservation-ontario.on.ca
Plant recognition terms
Leaf shape
Arrangement
entire toothed/serrated compoundleaf
lance shaped heart shaped tear drop shaped
opposite alternate
lobedleaf
egg shaped
Ligule- found at the inner base of the leaf, between where the leaf attaches to the main stem and the stem itself. Commonly forms a translucent membrane or a fringe of hairs.
Stem sheath- portion of leaf that wraps around and joins leaf to stem.
Lenticel- small openings in the bark of some trees that allow air exchange.
terminalbud
lateralbud
lateral budsdivergent
lateral budsappressed
Buds
Stems/Bark
Manitoba maple(Acer negundo)
Manitoba maple(Acer negundo)
compound,irregularlylobedleafcompound,irregularlylobedleaf
bark ManitobamapleseedsManitobamapleseedsbark
Manitoba maple(Acer negundo)
Plant Type: Tree.
Arrangement:Opposite.
Leaf:Compoundleaf,threetosevenleaflets,irregularlylobed.
Bark:Greyishbrownbark.Maturebarkwithnarrowfirmridges.
Seed/Flowers:Wingedseedsjoinedata<45°angle.
Buds/Stem:Eggshapedbudsarecoveredinfinewhitehairs.Youngtwigsareshinygreen-purplewithawaxywhitecoatingthatrubsoff.
Habitat:Dry,butmostlyfreshsoilsinvarioushabitats,mostofteninfloodplains.
Similar native species:Ashspecies(Fraxinus spp.) havecompoundleaveswithnolobes;terminalbuds are pointed. Elderberry (Sambucus spp.)aremulti-stemmedshrubswithclustersofberry-likefruit.
Norway maple(Acer platanoides)
Norway maple(Acer platanoides)
mature barkmature bark NorwaymapleseedsNorwaymapleseeds
whitesap-foundinleafstemwhitesap-foundinleafstem
Norway maple(Acer platanoides)
Plant type: Tree.
Arrangement:Opposite.
Leaf:Fivelobed(widerthanlong)leaf,darkgreentopurple.Black-spotfungusonleavesiscommon.White,milkysapfoundinleafstem.
Bark:Finelyridgeddarkbark.
Seed/Flowers:Wingedseed;typicalofmaples.Joinedata180ºangle.
Buds/Stem:Terminalbudisplumpandblunttippedstembudsareround,softandreddishbrown.Twigsareshinyreddishbrown.
Habitat:Drytomoistsoilsinforestandsuccessionalareas,oftenusedasurbanstreettree.
Similar native species:Sugarmaple(Acer saccharum)leavesarefivelobedandlongerthanwide.Budsonsugarmaplearesharppointed,notbluntandseedsforma“U”shape.Clearsapisfoundinleafstem.Norwaymaplebarkcanbemistakenforwhiteashwhennotinleaf.However,thebarkisconsiderablydarkerthanwhiteash.
European or black alder(Alnus glutinosa)
European or black alder(Alnus glutinosa)
leavesleaves
longstalked‘fruit’(non-native)longstalked‘fruit’(non-native)barkshowing‘lenticels’barkshowing‘lenticels’
European or black alder(Alnus glutinosa)
Plant type:Shrub/smalltree.
Arrangement:Alternate.
Leaf:Oblongshapedleafwithblunttip.
Bark:Grayishdarkbrownwithobvious,silverlenticels.
Seed/Flowers:Pine-coneshapedfruitonEuropeanalderislarge(about2cm),andonalongstalk(>1cm).
Buds/Stem:Budsare‘lightbulb’shaped.
Habitat:Moistandwetsoilsinandaroundwetlandsandwaterways.
Similar native species:Speckledalder(Alnus incana ssp. rugosa)leavesarewedgeshapedandcometoapoint.Seedconeisshortstalked(stemsare≤.5cm).Thespeckledalderisamulti-stemmedtallshrub,whileEuropeanaldergrowsmorelikeatreefromasinglestem.
winged euonymus(E. alatus)
winged euonymus(E. alatus)
runningstrawberryandEuropeanspindletreerunningstrawberryandEuropeanspindletree
two-partedseedofwinged euonymus
two-partedseedofwinged euonymus
four-partedseedofnativeburningbushandEuropeanspindletree
four-partedseedofnativeburningbushandEuropeanspindletree
Plant type:Shrub/smalltree.
Arrangement:Bothspeciesareoppositeintheir arrangement.
Leaf:Bothspecieshaveafinelytoothed,tearshapedleafthatiswidestatthemiddle.
Bark:Youngbarksmoothandgreen(E.europaeus)withprominentraisedridgesonE.alatusstems.Roughtextureandpeelingbarkwhenmature.
Seed/Flowers:Europeanspindletreehasafour-partedfruitwithyellowishflowersinsmallclusters.Wingedeuonymushasatwopartedfruit,withyellow/greenflowers.
Buds/Stem:Europeanspindletreestemsaregreenandsmooth,wingedeuonymushasprominentwingedstems.
Habitat:Drytofreshsoilsinsuccessionalareasandforests.
Similar native species:Nativestrawberrybush(E. obovatus)isagroundhuggingvine;leafwideratthetipnotthemiddle.Nativeburningbush(E. Autopurpurea) ismostoftenmistakenforEuropeanspindletree.Ithasafour-partedseed,butdifferswithdarkpurpleflowersinlargeclustersinthespring.
European spindletree & winged euonymus(Euonymus europaeus & E. alatus)
non-native bush honeysuckles(Lonicera spp.)
non-native bush honeysuckles(Lonicera spp.)
flowerflowerbarkbark
fruitfruit
non-native bush honeysuckles(Lonicera spp.)
Plant type:Shrubcanbe1.5mto4mtall.
Arrangement:Opposite.
Leaf:Allspecieshaveleaveswithsmoothmargins.Leafcanbehairyorsmooth.
Bark:Generallypapery.
Seed/Flowers:Showyflowers(variouscolours:white,pink,yellow,orange);fruittypicallytwobrightredberriesfusedtogether.
Buds/Stem:Brittlestems.Growthformtendstobemessyandtangled.Olderstemsarehollow.
Habitat:Various:drytofreshsoilsinforestandsuccessionalareas.
Similar native species:Bush(Diervilla lonicera)is<1minheight,fly(L. canadensis)is<1.5minheight,Glaucous(L. dioica) and hairy (L. hirsuta)honeysucklearebothvines.Olderstemsaresolid.Difficulttoidentifythesespecies.Consultanexpertifuncertain.
berriesberries
common & glossy buckthorn(Rhamnus cathartica & R. frangula)
common & glossy buckthorn(Rhamnus cathartica & R. frangula)
lenticelslenticels
common & glossy buckthorn(Rhamnus cathartica & R. frangula)
Plant type:Shrub/smalltree.
Arrangement:Commonbuckthornaresub-opposite(almostopposite).Glossybuckthornarealternate.
Leaf:Thecommonbuckthornleafiseggshaped,edgeoftheleafis“pebbled”(smallroundedteeth).Veinsconvergingtowardleaftop.Theglossybuckthornleafismoreslender(teardropshaped)andsmoothmargined.
Bark:Smooth,youngbarkwithprominentraisedpatchesorlenticels;roughtextureandpeelingbarkwhenmature.
Seed/Flowers:Flowersaregreen-yellowish,smallandinconspicuous.Greenberriesbecomingpurplish/blackinlatesummer,berry>1cmindiameter.
Buds/Stem:Commonbuckthornhasthorn-liketiponmanytwigs.Glossybuckthornbudshavenobudscalesandlackthornytipstotwigs.
Habitat: Various-forest,thickets,meadows,drytomoistsoils.
Similar native species:Nativedogwoods,whichlackthethorny“tip”.Nativedogwoodsaretrulyoppositeinarrangementoftwigs;onlyalternateleaved(pagoda)dogwoodhasalternatebranching.
dog-strangling vine(Cynanchum rossicum & C. nigrum)
dog-strangling vine(Cynanchum rossicum & C. nigrum)
C. rossicumflowersC. rossicumflowers
seedpodsseedpods
dog-strangling vine(Cynanchum rossicum & C. nigrum)
Plant type:Herb,twiningvine.
Arrangement:Opposite.
Leaf:Lanceshaped,smoothmargin(edge).
Bark:n/a.
Seed/Flowers:Beanshapedseedpodwithseedsattachedtodowny‘umbrellas’.Flowers-pink(C. rossicum) or purple (C. nigrum)withfivepetals.
Buds/Stem:n/a.
Habitat:Drytomoistsoils;moredominantinmeadowsandwoodlandedges.
Similar native species:Swampmilkweed(Asclepias incarnata),isanuprightplant,typicallyfoundinwetlandhabitats.
garlic mustard(Alliaria petiolata)
garlic mustard(Alliaria petiolata)
young/firstyeargrowthyoung/firstyeargrowth secondyeargrowth&flowerssecondyeargrowth&flowers
garlic mustard(Alliaria petiolata)
Plant type:Herb.
Arrangement:Alternate.
Leaf:Sawtoothlikeedge,elongatedheartshapewithprominentveins.Garlic/onionsmellwhencrushed.Young(firstyear)leavesarekidneyshaped.
Bark:n/a.
Seed/Flowers:Clusterofsmallwhiteflowerswithfourpetals.Smallblack<1mmroundedseedfoundinelongated‘tube-like’seedpods(similartoabeanpod).
Buds/Stem:n/a.
Habitat:Various–drytomoistsoils,inallhabitattypes,lessofteninmeadows.
Similar native species:n/a.
flowerandleavesflowerandleaves
giant hogweed(Heracleum mantegazzianum)giant hogweed
(Heracleum mantegazzianum)
stemwithpurplespotsstemwithpurplespots youngstemyoungstem
giant hogweed(Heracleum mantegazzianum)
Plant type:Herb.Matureplantscanbeover3mtall.
Arrangement:Alternate.
Leaf:Lobedleaf1-2mwide,lobessharp-pointed.
Bark:n/a.
Seed/Flowers:Small,whiteflowersinalargeumbrella-shapedcluster,.75mwide.
Buds/Stem:Hairystemwithpurplespots.
Habitat:Freshtowetsoilsinforests,swamps,meadows,marshes.
Similar native species:Cowparsnip(Heracleum maximum)–hassmallerflowers,nopurplespotsonstems.Angelica(Angelica atropurpurea)hasarounded-toppedflowerclusterandleavesdividedintomanyleafletsandthestemishairless.
Donottouchthisplantbecauseitispoisonous.Ifyoudo,washyourskinimmediatelyincoolsoapywateranddonotexposetheareatosunlight.
Himalayan balsam(Impatiens glandulifera)
Himalayan balsam(Impatiens glandulifera)
flowerflower
HimalayanbalsamflowerandstemHimalayanbalsamflowerandstemnativejewelweedflowerandstemnativejewelweedflowerandstem
Himalayan balsam(Impatiens glandulifera)
Plant Type:Herb,1-3minheight.
Arrangement:Alternate.
Leaf:Lanceshapedleafwithsharplytoothededges.
Bark:n/a.
Seed/Flowers:Flowers-pink,largeandshowy.
Buds/Stem:Fleshyreddishstem.
Habitat:Wetandmoistsoilsinwetlandsandfloodplains.
Similar native species:Touch-me-notsorjewelweeds(Impatiens capensis)-haveorangeoryellowflowers.Leafmoreoblongshapedandcoarselytoothed.
Japanese knotweed(Polygonum cuspidatum)
Japanese knotweed(Polygonum cuspidatum)
typicalgrowthformtypicalgrowthform
stemstem flowerflower
Japanese knotweed(Polygonum cuspidatum)
Plant Type:Herb,2-4minheight.
Arrangement:Alternate.
Leaf:Teardropshaped,sharppointed,darkgreen,flattenedatbase.
Bark:n/a.
Seed/Flowers:Floweringstalkofmanysmallgreenish-whiteflowers.
Buds/Stem:Largeplantwitha‘bamboo-like’stem.Stemlightgreenmaturingtotancolour.
Habitat:Moisttowetsoilsfoundinwetlands,water-coursesandroadsideditches.
Similar native species: none.
reed or giant manna grass(Glyceria maxima)
reed or giant manna grass(Glyceria maxima)
entire plantentire plant
tube-likeinfoldtube-likeinfoldflowerclusterflowercluster
reed or giant manna grass(Glyceria maxima)
Plant type:Grass.Matureplantsgrowover1.5m.
Arrangement:Alternate.
Leaf:Stemsheathsnearthebaseareslightlyrough.Ligulewhenpulledfromstemisinfolded(tube-like).Basereddishinspring,butfadingasseasonprogresses.Red/purpletingeoftenstilldetectableonoutersheathatbaseofsteminlateseason.Stemsarerobust;fleshyandthick.Incrosssectiontheyaresomewhatflattenedorovalinshape.
Bark:n/a.
Seed/Flowers:Uprightwithacascadingbroomlike‘flower’head.
Buds/Stem:n/a.
Habitat:Moisttofreshsoilsinopenwetlandsandedgesofriverbank.
Similar native species:Thenativespeciesofmannagrass(Glyceria sp.), includingtallnorthern,easternandrattlesnakegrass,havesmoothstemsheathsandfloweringheadstendtobendoverandnotstandupright.Rarelydothesenativespeciesexceed1.5minheight.
“flower”head“flower”head ligule
close-upofflower
common reed(Phragmites australis)
common reed
common reed(Phragmites australis)
Plant type:Grass.
Arrangement:Alternate.
Leaf:Broadleaf>1cmwide.
Bark:n/a.
Seed/Flowers:Densecascading‘broom-like’flowerhead.‘Cottony’inappearancewhenmature.
Buds/Stem:Stemsroughandridged,liguleadenselyhairyband.Hairybandlessconspicuouslaterinseason.Matureplants>3mtall.
Habitat:Moisttowetsoils.Foundinwetlands,water-coursesandroadsideditches.
Similar native species:Speciesofmannagrass(Glyceria sp.)includingtallnorthern,easternandrattlesnakegrass. Anativecommonreedexistsbuthasasmoothstemandtheliguleisnothairy.Itisalsoquiterare.
non-variegatedformnon-variegatedform
“umbrella-like”flower;variegatedform“umbrella-like”flower;variegatedform
goutweed(Aegopodium podagraria)
goutweed
goutweed(Aegopodium podagraria)
Plant type:Herb.
Arrangement:Alternate.
Leaf:Compoundleafwithserratededges,canbenon-variegatedorvariegatedgreenandwhite.
Bark:n/a.
Seed/Flowers:Flattopped‘umbrellalike’flowerheadwithmanysmallwhiteflowers.
Buds/Stem:n/a.
Habitat:Various–drytofreshsoilsinforestandsuccessionalareas.Anescapeefromresidentialgardens.
Similar native species: Water hemlock (Cicuta maculata) –foundinwetareas.Angelica(Angelica atropurpurea)hassimilarcompoundleavesbutgrowsupto2mtall.Goldenalexanders(Zizia aurea)isararenativeplantfoundinfloodplainswithsimilarbutmoreslenderleavesandyellowflowersinMaytoJune.
vine-likegrowthformvine-likegrowthform
English ivy(Hedera helix)
English ivy(Hedera helix)
English ivy(Hedera helix)
Plant Type:Herb/Vine.
Arrangement:Alternate.
Leaf: Three-lobedevergreenleafwithlightcolouredveins.
Bark:n/a.
Buds/Stem:Growsasgroundcoverandvine.
Habitat:Avarietyofsoilsfromdrytofreshinsuccessionalandforestedhabitats.Anescapeefromresidentialgardens.
Similar native species: none.
periwinkle(Vinca minor)
periwinkle(Vinca minor)
leavesleaves
flowersflowers
periwinkle(Vinca minor)
Plant type:Herb.
Arrangement:Opposite.
Leaf:Lanceshaped,shiny,evergreen.
Bark:n/a.
Seed/Flowers:Showyblue/purpleflowers.
Buds/Stem:Acreeping,trailinggroundplant.
Habitat:Drytofreshsoilsinsuccessionalareas,forestsandalongstreamsandwetlands.Typicallyassociatedwithresidentialgardens.
Similar native species:Wintergreen(Gaultheria procumbens)hassimilarleaves,buthasanobviousmintysmellwhentheleafiscrushed.Partridgeberry(Mitchella repens)isalsofoundinforests.Similarleavesbutmoreroundtoegg-shapedwithprominentpaleveins,flowersarewhitefollowedbyredberries.
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