Native plants · Illinois

Native plants of Knox County

490 plant species are recorded as native to Illinois in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in Knox County by USDA PLANTS. 217 of them have growing records you can filter by light, moisture, height and estimated cold hardiness. 5 more species are listed as both native and introduced and kept in a separate section.

County summary · USDA PLANTS and Kew WCVP

Knox County, Illinois

Native species: 490 Typical Illinois county: 641 (median of 102 counties)
Garden-ready natives: 217 Typical Illinois county: 272
Share by type (all 490 native species): Percent of the 490 native species in each growth type

Tree 10% (51)
Shrub 3% (15)
Wildflower (forb) 63% (311)
Grass or grass-like 16% (80)
Vine 4% (20)
Fern 3% (13)

Wildflowers make up the largest share of the native list (63%), followed by grasses and grass-like plants (16%).

Recorded native ranges can include long-established populations that spread from gardens; check your state’s native plant society list for local guidance. How native status is decided.

ZIP codes mainly in this county fall in USDA hardiness zone 5b (2023 map).

The native plant list

Garden-ready natives 217

Native species with PLANTS growing records (height, light, moisture, minimum temperature). “—” means PLANTS has no value.

Garden-ready native plants of Knox County, Illinois
Plant	Type	Height	Light	Water use	Hardy to
Allegheny blackberry Rubus allegheniensis	Shrub	6 ft	Shade-tolerant	Medium	Zone 4b
American basswood Tilia americana	Tree	100 ft	Shade-tolerant	Medium	Zone 2b
American bellflower Campanulastrum americanum	Wildflower (forb)	6 ft	Shade-tolerant	Medium	Zone 12b
American bittersweet Celastrus scandens	Vine	15 ft	Shade-tolerant	High	Zone 3b
American bur-reed Sparganium americanum	Wildflower (forb)	3.2 ft	Sun–part shade	High	Zone 4a
American elm Ulmus americana	Tree	120 ft	Sun–part shade	High	Zone 2b
American hazelnut Corylus americana	Shrub	10 ft	Sun–part shade	Medium	Zone 4a
American licorice Glycyrrhiza lepidota	Wildflower (forb)	4 ft	Sun–part shade	High	Zone 3b
American plum Prunus americana	Tree	24 ft	Sun	Medium	Zone 3b
American pokeweed Phytolacca americana	Wildflower (forb)	7.3 ft	Shade-tolerant	Medium	Zone 4a
American red raspberry Rubus idaeus	Shrub	6 ft	Shade-tolerant	—	Zone 1a
American sycamore Platanus occidentalis	Tree	100 ft	Sun–part shade	High	Zone 4a
American vetch Vicia americana	Vine	1.3 ft	Sun	Low	Zone 3b
American water horehound Lycopus americanus	Wildflower (forb)	1.8 ft	Shade-tolerant	High	Zone 3b
American water plantain Alisma subcordatum	Wildflower (forb)	6 in	Sun	High	Zone 4a
American water-willow Justicia americana	Wildflower (forb)	2.5 ft	Shade-tolerant	Medium	Zone 4b
arrowleaf tearthumb Polygonum sagittatum	Vine	1 ft	Sun	Medium	Zone 6a
Atlantic camas Camassia scilloides	Wildflower (forb)	2.5 ft	Shade-tolerant	Medium	Zone 4b
awlfruit sedge Carex stipata	Grass or grass-like	3.5 ft	Shade-tolerant	Medium	Zone 3b
beaked agrimony Agrimonia rostellata	Wildflower (forb)	2.3 ft	Sun–part shade	Medium	Zone 4a
bearded beggarticks Bidens aristosa	Wildflower (forb)	3.5 ft	Sun–part shade	High	Zone 12b
Bicknell's sedge Carex bicknellii	Grass or grass-like	3.4 ft	Shade-tolerant	Low	Zone 3b
big bluestem Andropogon gerardii	Grass or grass-like	6 ft	Sun	Low	Zone 2b
bigtooth aspen Populus grandidentata	Tree	65 ft	Sun	High	Zone 3a
bitternut hickory Carya cordiformis	Tree	75 ft	Sun	Medium	Zone 2b
black cherry Prunus serotina	Tree	80 ft	Sun	Medium	Zone 4a
black oak Quercus velutina	Tree	80 ft	Sun–part shade	Medium	Zone 4a
black raspberry Rubus occidentalis	Shrub	6 ft	Sun–part shade	Medium	Zone 4b
black walnut Juglans nigra	Tree	100 ft	Sun	High	Zone 4b
black willow Salix nigra	Tree	100 ft	Sun	High	Zone 1b
blackeyed Susan Rudbeckia hirta	Wildflower (forb)	1 ft	Sun	Medium	Zone 5a
blackhaw Viburnum prunifolium	Tree	16 ft	Shade-tolerant	Medium	Zone 4a
blackjack oak Quercus marilandica	Tree	25 ft	Sun	Low	Zone 6a
blue cohosh Caulophyllum thalictroides	Wildflower (forb)	2.5 ft	Shade-tolerant	Medium	Zone 4a
blunt broom sedge Carex tribuloides	Grass or grass-like	3 ft	Shade-tolerant	Medium	Zone 4b
blunt spikerush Eleocharis obtusa	Grass or grass-like	1.6 ft	Sun	Medium	Zone 11a
bluntleaf bedstraw Galium obtusum	Wildflower (forb)	1.5 ft	Shade-tolerant	High	Zone 4a
boxelder Acer negundo	Tree	60 ft	Shade-tolerant	Medium	Zone 2b
bristly buttercup Ranunculus hispidus	Wildflower (forb)	2.5 ft	Shade-tolerant	Medium	Zone 4a
broadleaf arrowhead Sagittaria latifolia	Wildflower (forb)	4.9 ft	Sun	High	Zone 4a
broadleaf cattail Typha latifolia	Wildflower (forb)	5 ft	Sun–part shade	High	Zone 3b
broom sedge Carex scoparia	Grass or grass-like	2.5 ft	Shade-tolerant	High	Zone 3b
buffalograss Bouteloua dactyloides	Grass or grass-like	6 in	Sun	Medium	Zone 3b
bulbous bittercress Cardamine bulbosa	Wildflower (forb)	1.4 ft	Shade-tolerant	Medium	Zone 4a
bur oak Quercus macrocarpa	Tree	100 ft	Sun–part shade	Medium	Zone 3b
burningbush Euonymus atropurpureus	Tree	10 ft	Shade-tolerant	Low	—
butternut Juglans cinerea	Tree	80 ft	Sun	Medium	Zone 4a
calico aster Symphyotrichum lateriflorum	Wildflower (forb)	4 ft	Sun	Medium	Zone 4a
Canada germander Teucrium canadense	Wildflower (forb)	3.3 ft	Sun–part shade	High	Zone 3a
Canada goldenrod Solidago canadensis	Wildflower (forb)	3.5 ft	Sun	Medium	Zone 3a
Canada wildrye Elymus canadensis	Grass or grass-like	3 ft	Shade-tolerant	Medium	Zone 3a
Canadian horseweed Conyza canadensis	Wildflower (forb)	5 ft	Sun	Medium	Zone 12b
Canadian lousewort Pedicularis canadensis	Wildflower (forb)	1.3 ft	Shade-tolerant	Medium	Zone 3a
Canadian milkvetch Astragalus canadensis	Wildflower (forb)	6 in	Sun	Medium	Zone 3b
Canadian plum Prunus nigra	Tree	9 ft	Sun	—	Zone 9b
Carolina rose Rosa carolina	Shrub	5 ft	Sun–part shade	Low	Zone 3a
chinquapin oak Quercus muehlenbergii	Tree	70 ft	Sun	Medium	Zone 4a
chokecherry Prunus virginiana	Tree	25 ft	Sun	Medium	Zone 3a
common blue violet Viola sororia	Wildflower (forb)	4 in	Sun–part shade	High	Zone 4b
common blue wood aster Symphyotrichum cordifolium	Wildflower (forb)	5 ft	Sun	Low	Zone 3b
common cowparsnip Heracleum maximum	Wildflower (forb)	8 ft	Sun	High	Zone 3b
common duckweed Lemna minor	Wildflower (forb)	—	Sun	High	Zone 3b
common evening primrose Oenothera biennis	Wildflower (forb)	5 ft	Sun	Medium	Zone 4b
common goldstar Hypoxis hirsuta	Wildflower (forb)	10 in	Sun–part shade	Medium	Zone 4a
common hackberry Celtis occidentalis	Tree	60 ft	Shade-tolerant	Low	Zone 2b
common hoptree Ptelea trifoliata	Tree	25 ft	Sun–part shade	High	Zone 4a
common ninebark Physocarpus opulifolius	Shrub	10 ft	Sun	Low	Zone 4a
common selfheal Prunella vulgaris	Wildflower (forb)	1.5 ft	Sun–part shade	Medium	Zone 3b
common serviceberry Amelanchier arborea	Tree	36 ft	Shade-tolerant	Medium	Zone 2b
common sneezeweed Helenium autumnale	Wildflower (forb)	4.9 ft	Sun	Medium	Zone 3a
composite dropseed Sporobolus compositus	Grass or grass-like	3 ft	Sun	Low	Zone 3b
coon's tail Ceratophyllum demersum	Wildflower (forb)	—	Sun–part shade	High	Zone 3b
coralberry Symphoricarpos orbiculatus	Shrub	2 ft	Sun–part shade	High	Zone 5a
crested sedge Carex cristatella	Grass or grass-like	3 ft	Shade-tolerant	High	Zone 4a
cup plant Silphium perfoliatum	Wildflower (forb)	6 ft	Sun–part shade	—	Zone 2b
cursed buttercup Ranunculus sceleratus	Wildflower (forb)	2 ft	Shade-tolerant	High	Zone 12b
cutleaf coneflower Rudbeckia laciniata	Wildflower (forb)	8.2 ft	Shade-tolerant	Low	Zone 3b
devil's beggartick Bidens frondosa	Wildflower (forb)	4 ft	Sun–part shade	Medium	Zone 12a
devil's darning needles Clematis virginiana	Vine	15 ft	Sun–part shade	Medium	Zone 3b
ditch stonecrop Penthorum sedoides	Wildflower (forb)	2.6 ft	Sun–part shade	Medium	Zone 4b
dotted smartweed Polygonum punctatum	Wildflower (forb)	3.2 ft	Sun	Medium	Zone 10b
downy yellow violet Viola pubescens	Wildflower (forb)	1.3 ft	Shade-tolerant	Medium	Zone 4a
eastern cottonwood Populus deltoides	Tree	190 ft	Sun	High	Zone 3a
eastern narrowleaf sedge Carex amphibola	Grass or grass-like	2 ft	Shade-tolerant	Medium	Zone 7a
eastern purple coneflower Echinacea purpurea	Wildflower (forb)	1.2 ft	Sun	Medium	Zone 4a
eastern redbud Cercis canadensis	Tree	30 ft	Shade-tolerant	Low	Zone 4b
eastern redcedar Juniperus virginiana	Tree	50 ft	Sun–part shade	Low	Zone 3a
eastern woodland sedge Carex blanda	Grass or grass-like	2 ft	Shade-tolerant	High	Zone 4b
field horsetail Equisetum arvense	Fern	11 in	Sun–part shade	High	Zone 3a
field pussytoes Antennaria neglecta	Wildflower (forb)	1 ft	Sun	Low	Zone 3b
fowl mannagrass Glyceria striata	Grass or grass-like	5.7 ft	Shade-tolerant	Medium	Zone 3b
fox sedge Carex vulpinoidea	Grass or grass-like	3.2 ft	Sun–part shade	Medium	Zone 3b
foxglove beardtongue Penstemon digitalis	Wildflower (forb)	4 ft	Shade-tolerant	Low	Zone 3b
Frank's sedge Carex frankii	Grass or grass-like	2 ft	Shade-tolerant	High	Zone 5a
fringeleaf wild petunia Ruellia humilis	Wildflower (forb)	2.6 ft	Shade-tolerant	Low	Zone 4a
Georgia bulrush Scirpus georgianus	Grass or grass-like	4.5 ft	Sun–part shade	Medium	Zone 3b
giant goldenrod Solidago gigantea	Wildflower (forb)	8.2 ft	Sun–part shade	Medium	Zone 4a
gray dogwood Cornus racemosa	Shrub	10 ft	Shade-tolerant	Medium	Zone 2b
gray goldenrod Solidago nemoralis	Wildflower (forb)	2 ft	Sun	Medium	Zone 4a
great St. Johnswort Hypericum ascyron	Wildflower (forb)	5 ft	Sun	Medium	Zone 5a
greater straw sedge Carex normalis	Grass or grass-like	5 ft	Shade-tolerant	High	Zone 4a
green bulrush Scirpus atrovirens	Grass or grass-like	5.9 ft	Sun	Medium	Zone 2a
groundnut Apios americana	Vine	1 ft	Shade-tolerant	Medium	Zone 5a
hairy white oldfield aster Symphyotrichum pilosum	Wildflower (forb)	3 ft	Shade-tolerant	Medium	Zone 4a
hairyfruit sedge Carex trichocarpa	Grass or grass-like	3.5 ft	Sun–part shade	High	Zone 4a
hardstem bulrush Schoenoplectus acutus	Grass or grass-like	9.8 ft	Sun	High	Zone 3b
harvestlice Agrimonia parviflora	Wildflower (forb)	6 ft	Sun–part shade	High	Zone 4a
honeylocust Gleditsia triacanthos	Tree	70 ft	Sun	Medium	Zone 3b
hophornbeam Ostrya virginiana	Tree	45 ft	Shade-tolerant	Low	Zone 3b
Indiangrass Sorghastrum nutans	Grass or grass-like	6 ft	Sun	Medium	Zone 3b
Indianhemp Apocynum cannabinum	Wildflower (forb)	3.3 ft	Sun–part shade	High	Zone 3a
inland rush Juncus interior	Grass or grass-like	3 ft	Sun–part shade	Medium	Zone 3b
interrupted fern Osmunda claytoniana	Fern	4 ft	Shade-tolerant	High	Zone 3b
Jack in the pulpit Arisaema triphyllum	Wildflower (forb)	1.5 ft	Shade-tolerant	High	Zone 5b
Jerusalem artichoke Helianthus tuberosus	Wildflower (forb)	9.8 ft	Sun–part shade	Low	Zone 3a
jewelweed Impatiens capensis	Wildflower (forb)	4.9 ft	Shade-tolerant	Medium	Zone 10b
leadplant Amorpha canescens	Shrub	4 ft	Shade-tolerant	Low	Zone 3b
leafy pondweed Potamogeton foliosus	Wildflower (forb)	—	Sun	High	Zone 3b
little barley Hordeum pusillum	Grass or grass-like	1.2 ft	Sun	Medium	Zone 10b
little bluestem Schizachyrium scoparium	Grass or grass-like	3 ft	Sun	Low	Zone 3b
littleleaf buttercup Ranunculus abortivus	Wildflower (forb)	2.8 ft	Shade-tolerant	Medium	Zone 3a
longleaf pondweed Potamogeton nodosus	Wildflower (forb)	—	Sun	High	Zone 3b
Mexican muhly Muhlenbergia mexicana	Grass or grass-like	3 ft	Sun–part shade	Medium	Zone 4a
Missouri goldenrod Solidago missouriensis	Wildflower (forb)	3 ft	Sun–part shade	Low	Zone 3b
Missouri ironweed Vernonia missurica	Wildflower (forb)	6 ft	Sun	Medium	Zone 4a
Missouri River willow Salix eriocephala	Tree	52 ft	Shade-tolerant	High	Zone 3b
mockernut hickory Carya tomentosa	Tree	85 ft	Sun–part shade	Medium	Zone 4a
nannyberry Viburnum lentago	Tree	28 ft	Shade-tolerant	Medium	Zone 4a
New Jersey tea Ceanothus americanus	Shrub	3 ft	Shade-tolerant	Low	Zone 4b
nodding beggartick Bidens cernua	Wildflower (forb)	3.2 ft	Sun–part shade	High	Zone 12a
nodding fescue Festuca subverticillata	Grass or grass-like	3 ft	Sun–part shade	Medium	Zone 3a
nodding waternymph Najas flexilis	Wildflower (forb)	2.5 ft	Sun–part shade	High	Zone 12a
northern maidenhair Adiantum pedatum	Fern	1.3 ft	Shade-tolerant	Medium	Zone 3b
northern red oak Quercus rubra	Tree	81 ft	Sun–part shade	Medium	Zone 3b
Ohio buckeye Aesculus glabra	Tree	68 ft	Shade-tolerant	Medium	Zone 4a
oval-leaf sedge Carex cephalophora	Grass or grass-like	2.6 ft	Sun–part shade	Low	Zone 4a
pale purple coneflower Echinacea pallida	Wildflower (forb)	1.2 ft	Sun	Medium	Zone 4a
pale touch-me-not Impatiens pallida	Wildflower (forb)	8.2 ft	Shade-tolerant	Medium	Zone 10b
partridge pea Chamaecrista fasciculata	Wildflower (forb)	2.4 ft	Shade-tolerant	Medium	Zone 7a
Pennsylvania bittercress Cardamine pensylvanica	Wildflower (forb)	1.5 ft	Shade-tolerant	Medium	Zone 4a
Pennsylvania smartweed Polygonum pensylvanicum	Wildflower (forb)	3.9 ft	Sun	Medium	Zone 10b
Philadelphia fleabane Erigeron philadelphicus	Wildflower (forb)	2.8 ft	Sun–part shade	Medium	Zone 4b
pinnate prairie coneflower Ratibida pinnata	Wildflower (forb)	4 ft	Sun	Medium	Zone 3b
porcupinegrass Hesperostipa spartea	Grass or grass-like	4 ft	Sun	Medium	Zone 3b
poverty rush Juncus tenuis	Grass or grass-like	1.5 ft	Sun–part shade	Medium	Zone 3b
prairie blazing star Liatris pycnostachya	Wildflower (forb)	3.5 ft	Sun	Medium	Zone 4a
prairie cordgrass Spartina pectinata	Grass or grass-like	8 ft	Sun	High	Zone 3b
prairie crab apple Malus ioensis	Tree	25 ft	Sun	Medium	Zone 4b
prairie Junegrass Koeleria macrantha	Grass or grass-like	1.5 ft	Shade-tolerant	High	Zone 3b
prairie willow Salix humilis	Shrub	10 ft	Sun–part shade	High	Zone 3a
purple lovegrass Eragrostis spectabilis	Grass or grass-like	11 in	Sun	Low	Zone 3a
purple prairie clover Dalea purpurea	Wildflower (forb)	3 ft	Sun	Medium	Zone 3b
purpletop tridens Tridens flavus	Grass or grass-like	2.5 ft	Sun	Low	Zone 5a
quaking aspen Populus tremuloides	Tree	65 ft	Sun	High	Zone 1a
rattlesnake fern Botrychium virginianum	Fern	1.4 ft	Shade-tolerant	Medium	Zone 3b
red mulberry Morus rubra	Tree	70 ft	Shade-tolerant	Medium	Zone 4a
reed canarygrass Phalaris arundinacea	Grass or grass-like	5 ft	Sun	High	Zone 3b
rice cutgrass Leersia oryzoides	Grass or grass-like	4.9 ft	Sun	High	Zone 4a
riverbank grape Vitis riparia	Vine	45 ft	Sun–part shade	Medium	Zone 4a
rough avens Geum laciniatum	Wildflower (forb)	3.1 ft	Sun–part shade	Medium	Zone 5a
roundhead lespedeza Lespedeza capitata	Wildflower (forb)	2.6 ft	Sun	Low	Zone 4b
rufous bulrush Scirpus pendulus	Grass or grass-like	4 ft	Sun	Medium	Zone 3b
sageleaf willow Salix candida	Shrub	6 ft	Sun–part shade	High	Zone 4a
sago pondweed Stuckenia pectinata	Wildflower (forb)	—	Sun	High	Zone 3b
sandbar willow Salix interior	Tree	30 ft	Sun	—	Zone 1a
sawtooth blackberry Rubus argutus	Shrub	8.2 ft	Sun	Medium	Zone 6a
sawtooth sunflower Helianthus grosseserratus	Wildflower (forb)	5 ft	Sun	Medium	Zone 3a
scarlet Indian paintbrush Castilleja coccinea	Wildflower (forb)	1.6 ft	Shade-tolerant	Medium	Zone 4b
shagbark hickory Carya ovata	Tree	75 ft	Sun–part shade	Medium	Zone 3a
shallow sedge Carex lurida	Grass or grass-like	3.2 ft	Sun–part shade	Medium	Zone 4a
shingle oak Quercus imbricaria	Tree	45 ft	Sun	Medium	Zone 5b
silver maple Acer saccharinum	Tree	90 ft	Sun–part shade	Medium	Zone 2b
slippery elm Ulmus rubra	Tree	85 ft	Shade-tolerant	High	Zone 3a
smallspike false nettle Boehmeria cylindrica	Wildflower (forb)	3.9 ft	Shade-tolerant	Medium	Zone 4a
smooth blue aster Symphyotrichum laeve	Wildflower (forb)	4 ft	Sun	Medium	Zone 3a
smooth horsetail Equisetum laevigatum	Fern	5 ft	Sun	Low	Zone 3b
smooth phlox Phlox glaberrima	Wildflower (forb)	3 ft	Sun–part shade	High	Zone 4b
smooth sumac Rhus glabra	Tree	12 ft	Sun	Low	Zone 4a
softstem bulrush Schoenoplectus tabernaemontani	Grass or grass-like	9 ft	Sun	High	Zone 3b
southern waternymph Najas guadalupensis	Wildflower (forb)	1 ft	Sun	High	Zone 3b
spotted St. Johnswort Hypericum punctatum	Wildflower (forb)	3 ft	Shade-tolerant	Medium	Zone 4a
star duckweed Lemna trisulca	Wildflower (forb)	4 in	Sun	High	Zone 3b
stiff goldenrod Oligoneuron rigidum	Wildflower (forb)	3.6 ft	Sun–part shade	Medium	Zone 3a
strawcolored flatsedge Cyperus strigosus	Grass or grass-like	3.2 ft	Sun	Medium	Zone 4a
sugar maple Acer saccharum	Tree	100 ft	Shade-tolerant	Medium	Zone 2b
swamp milkweed Asclepias incarnata	Wildflower (forb)	4.9 ft	Sun	High	Zone 3b
swamp smartweed Polygonum hydropiperoides	Wildflower (forb)	—	Sun	Medium	Zone 10b
sweet woodreed Cinna arundinacea	Grass or grass-like	4.9 ft	Shade-tolerant	Low	Zone 4a
switchgrass Panicum virgatum	Grass or grass-like	5 ft	Sun	Medium	Zone 3a
tall cinquefoil Potentilla arguta	Wildflower (forb)	3 ft	Sun–part shade	Medium	Zone 3b
tall hairy agrimony Agrimonia gryposepala	Wildflower (forb)	5.9 ft	Sun–part shade	Medium	Zone 3a
taperleaf water horehound Lycopus rubellus	Wildflower (forb)	1.6 ft	Shade-tolerant	High	Zone 5a
threelobe beggarticks Bidens tripartita	Wildflower (forb)	3.5 ft	Sun–part shade	High	Zone 12a
threepetal bedstraw Galium trifidum	Vine	10 in	Sun–part shade	High	Zone 3b
Torrey's rush Juncus torreyi	Grass or grass-like	3.1 ft	Sun	Medium	Zone 3b
trumpet creeper Campsis radicans	Vine	2 ft	Sun	Low	Zone 6a
Virginia bluebells Mertensia virginica	Wildflower (forb)	2.3 ft	Shade-tolerant	High	Zone 4b
Virginia creeper Parthenocissus quinquefolia	Vine	1 ft	Sun–part shade	Low	Zone 4b
Virginia threeseed mercury Acalypha virginica	Wildflower (forb)	3 ft	Sun–part shade	Medium	Zone 10b
Virginia water horehound Lycopus virginicus	Wildflower (forb)	4 ft	Shade-tolerant	High	Zone 4a
Virginia wildrye Elymus virginicus	Grass or grass-like	2.5 ft	Shade-tolerant	Medium	Zone 4b
water knotweed Polygonum amphibium	Wildflower (forb)	1 in	Sun	High	Zone 5a
western snowberry Symphoricarpos occidentalis	Shrub	3 ft	Sun–part shade	Low	Zone 3b
white ash Fraxinus americana	Tree	90 ft	Sun	High	Zone 4a
white avens Geum canadense	Wildflower (forb)	3.9 ft	Shade-tolerant	Medium	Zone 4a
white doll's daisy Boltonia asteroides	Wildflower (forb)	8 ft	Sun–part shade	Medium	Zone 3b
white oak Quercus alba	Tree	100 ft	Sun–part shade	Medium	Zone 3a
white panicle aster Symphyotrichum lanceolatum	Wildflower (forb)	6 ft	Sun–part shade	High	Zone 3b
white sagebrush Artemisia ludoviciana	Wildflower (forb)	3 ft	Sun	Low	Zone 4a
whitegrass Leersia virginica	Grass or grass-like	3.9 ft	Shade-tolerant	Medium	Zone 3a
wild bergamot Monarda fistulosa	Wildflower (forb)	4.9 ft	Sun–part shade	High	Zone 4a
wild blue phlox Phlox divaricata	Wildflower (forb)	3 ft	Sun–part shade	Medium	Zone 4a
winter bentgrass Agrostis hyemalis	Grass or grass-like	3.5 ft	Sun–part shade	High	Zone 4a
wirestem muhly Muhlenbergia frondosa	Grass or grass-like	2 ft	Shade-tolerant	Medium	Zone 3b
woodland bluegrass Poa sylvestris	Grass or grass-like	3 ft	Shade-tolerant	High	Zone 4a
yellow flatsedge Cyperus flavescens	Grass or grass-like	2 ft	Sun	Medium	Zone 11b
yellow marsh marigold Caltha palustris	Wildflower (forb)	2 ft	Sun	High	Zone 3b

Other native species recorded here 273

PLANTS has no growing records for these, so light, moisture, height and zone filters cannot include them. Many are wild species seldom sold by nurseries.

Allegheny monkeyflower Mimulus ringens
amberique-bean Strophostyles helvola
American bladdernut Staphylea trifolia
American burnweed Erechtites hieraciifolius
American false pennyroyal Hedeoma pulegioides
American ginseng Panax quinquefolius
American hogpeanut Amphicarpaea bracteata
American lopseed Phryma leptostachya
American white waterlily Nymphaea odorata
arrowleaf violet Viola sagittata
ashy sunflower Helianthus mollis
Aunt Lucy Ellisia nyctelea
bald spikerush Eleocharis erythropoda
balsam groundsel Packera paupercula
bastard toadflax Comandra umbellata
biennial beeblossom Oenothera gaura
big devils beggartick Bidens vulgata
bigbract verbena Verbena bracteata
birdfoot violet Viola pedata
blackseed plantain Plantago rugelii
blisterwort Ranunculus recurvatus
bloodroot Sanguinaria canadensis
bloody butcher Trillium recurvatum
blue ash Fraxinus quadrangulata
blue skullcap Scutellaria lateriflora
bluejacket Tradescantia ohiensis
bluntleaf sandwort Moehringia lateriflora
bottlebrush sedge Carex hystericina
bottomland aster Symphyotrichum ontarionis
bristly greenbrier Smilax tamnoides
brown widelip orchid Liparis liliifolia
browneyed Susan Rudbeckia triloba
button eryngo Eryngium yuccifolium
camphorweed Heterotheca subaxillaris
Canada lettuce Lactuca canadensis
Canadian anemone Anemone canadensis
Canadian blacksnakeroot Sanicula canadensis
Canadian clearweed Pilea pumila
Canadian honewort Cryptotaenia canadensis
Canadian wildginger Asarum canadense
Canadian woodnettle Laportea canadensis
Carolina geranium Geranium carolinianum
Carolina horsenettle Solanum carolinense
carpenter's square Scrophularia marilandica
clammy groundcherry Physalis heterophylla
clasping Venus' looking-glass Triodanis perfoliata
clustered blacksnakeroot Sanicula odorata
common boneset Eupatorium perfoliatum
common cinquefoil Potentilla simplex
common milkweed Asclepias syriaca
common moonseed Menispermum canadense
common threeseed mercury Acalypha rhomboidea
common yellow oxalis Oxalis stricta
compassplant Silphium laciniatum
Culver's root Veronicastrum virginicum
curlytop knotweed Polygonum lapathifolium
cutleaf grapefern Botrychium dissectum
cutleaf toothwort Cardamine concatenata
Davis' sedge Carex davisii
Dillenius' ticktrefoil Desmodium glabellum
dotted hawthorn Crataegus punctata
downy hawthorn Crataegus mollis
downy phlox Phlox pilosa
Drummond's aster Symphyotrichum drummondii
Dudley's rush Juncus dudleyi
dutchman's breeches Dicentra cucullaria
dwarf larkspur Delphinium tricorne
earleaf false foxglove Agalinis auriculata
early buttercup Ranunculus fascicularis
early goldenrod Solidago juncea
early wildrye Elymus macgregorii
earlyleaf brome Bromus latiglumis
eastern bottlebrush grass Elymus hystrix
eastern false rue anemone Enemion biternatum
eastern poison ivy Toxicodendron radicans
elmleaf goldenrod Solidago ulmifolia
Emory's sedge Carex emoryi
Equisetum ×ferrissii Equisetum ×ferrissii
evening campion Silene nivea
fall phlox Phlox paniculata
false mermaidweed Floerkea proserpinacoides
feathery false lily of the valley Maianthemum racemosum
feverwort Triosteum perfoliatum
fewleaf sunflower Helianthus occidentalis
field thistle Cirsium discolor
fleshy hawthorn Crataegus succulenta
flowering spurge Euphorbia corollata
fourleaf milkweed Asclepias quadrifolia
foxtail barley Hordeum jubatum
fragrant bedstraw Galium triflorum
fringed loosestrife Lysimachia ciliata
golden zizia Zizia aurea
goldenseal Hydrastis canadensis
great blue lobelia Lobelia siphilitica
great ragweed Ambrosia trifida
great waterleaf Hydrophyllum appendiculatum
Greek valerian Polemonium reptans
green carpetweed Mollugo verticillata
green milkweed Asclepias hirtella
hairy hawkweed Hieracium longipilum
hairy hedgenettle Stachys pilosa
hairy pagoda-plant Blephilia hirsuta
hairy wildrye Elymus villosus
hairy woodland brome Bromus pubescens
hairyjoint meadowparsnip Thaspium barbinode
heartleaf skullcap Scutellaria ovata
heavy sedge Carex gravida
hedge false bindweed Calystegia sepium
hemlock waterparsnip Sium suave
hoary frostweed Helianthemum bicknellii
hoary puccoon Lithospermum canescens
hoary ticktrefoil Desmodium canescens
hoary verbena Verbena stricta
horned pondweed Zannichellia palustris
Illinois pondweed Potamogeton illinoensis
Illinois ticktrefoil Desmodium illinoense
Indian-tobacco Lobelia inflata
Indianpipe Monotropa uniflora
inflated narrow-leaf sedge Carex grisea
jumpseed Polygonum virginianum
lanceleaf buckthorn Rhamnus lanceolata
lanceleaf fogfruit Phyla lanceolata
largebract ticktrefoil Desmodium cuspidatum
largebracted plantain Plantago aristata
largeflower bellwort Uvularia grandiflora
lateflowering thoroughwort Eupatorium serotinum
Leavenworth's sedge Carex leavenworthii
Leiberg's panicum Dichanthelium leibergii
licorice bedstraw Galium circaezans
longleaf groundcherry Physalis longifolia
longstyle sweetroot Osmorhiza longistylis
low false bindweed Calystegia spithamaea
lowland bladderfern Cystopteris protrusa
man of the earth Ipomoea pandurata
mapleleaf goosefoot Chenopodium simplex
mat sandbur Cenchrus longispinus
mayapple Podophyllum peltatum
meadow garlic Allium canadense
Mexican plum Prunus mexicana
Michigan lily Lilium michiganense
Missouri gooseberry Ribes missouriense
narrowleaf mountainmint Pycnanthemum tenuifolium
neckweed Veronica peregrina
needletip blue-eyed grass Sisyrinchium mucronatum
New England aster Symphyotrichum novae-angliae
nodding chickweed Cerastium nutans
nodding wakerobin Trillium flexipes
obovate beakgrain Diarrhena obovata
October lady's tresses Spiranthes ovalis
oneflowered broomrape Orobanche uniflora
orangefruit horse-gentian Triosteum aurantiacum
pale beardtongue Penstemon pallidus
pale dock Rumex altissimus
pale Indian plantain Arnoglossum atriplicifolium
paleleaf woodland sunflower Helianthus strumosus
palespike lobelia Lobelia spicata
Parlin's pussytoes Antennaria parlinii
Pennsylvania pellitory Parietaria pensylvanica
Pennsylvania sedge Carex pensylvanica
pointedleaf ticktrefoil Desmodium glutinosum
poverty dropseed Sporobolus vaginiflorus
prairie blue-eyed grass Sisyrinchium campestre
prairie milkweed Asclepias sullivantii
prairie rosinweed Silphium terebinthinaceum
prairie sunflower Helianthus petiolaris
prairie threeawn Aristida oligantha
puffsheath dropseed Sporobolus neglectus
purple giant hyssop Agastache scrophulariifolia
purple meadow-rue Thalictrum dasycarpum
purple milkweed Asclepias purpurascens
purple milkwort Polygala sanguinea
rabbit-tobacco Pseudognaphalium obtusifolium
ramp Allium tricoccum
red columbine Aquilegia canadensis
redwhisker clammyweed Polanisia dodecandra
Richardson's alumroot Heuchera richardsonii
robin's plantain Erigeron pulchellus
rock muhly Muhlenbergia sobolifera
rosy sedge Carex rosea
rough barnyardgrass Echinochloa muricata
rough hawkweed Hieracium scabrum
rough rattlesnakeroot Prenanthes aspera
roundseed St. Johnswort Hypericum sphaerocarpum
roundstem false foxglove Agalinis gattingeri
Schreber's aster Eurybia schreberi
sensitive fern Onoclea sensibilis
shining bedstraw Galium concinnum
Short's aster Symphyotrichum shortii
shortbeak arrowhead Sagittaria brevirostra
shortbeak sedge Carex brevior
shortspike watermilfoil Myriophyllum sibiricum
showy lady's slipper Cypripedium reginae
showy orchid Galearis spectabilis
showy ticktrefoil Desmodium canadense
shrubby lespedeza Lespedeza frutescens
sicklepod Arabis canadensis
silver false spleenwort Deparia acrostichoides
skyblue aster Symphyotrichum oolentangiense
sleepy silene Silene antirrhina
slender lespedeza Lespedeza virginica
slender yellow woodsorrel Oxalis dillenii
slenderleaf false foxglove Agalinis tenuifolia
small pondweed Potamogeton pusillus
smallflower fumewort Corydalis micrantha
smooth oxeye Heliopsis helianthoides
smooth Solomon's seal Polygonatum biflorum
snow trillium Trillium nivale
soft agrimony Agrimonia pubescens
soft fox sedge Carex conjuncta
Spanish gold Grindelia papposa
spinulose woodfern Dryopteris carthusiana
spotted geranium Geranium maculatum
spotted sandmat Chamaesyce maculata
spotted water hemlock Cicuta maculata
spreading chervil Chaerophyllum procumbens
spreading dogbane Apocynum androsaemifolium
stiff sunflower Helianthus pauciflorus
stiff tickseed Coreopsis palmata
swamp dock Rumex verticillatus
swamp verbena Verbena hastata
sweetscented joe pye weed Eutrochium purpureum
swollen duckweed Lemna gibba
tall blazing star Liatris aspera
tall thimbleweed Anemone virginiana
tall thistle Cirsium altissimum
tall thoroughwort Eupatorium altissimum
tall tickseed Coreopsis tripteris
Tennessee bladderfern Cystopteris tennesseensis
threeflower melicgrass Melica nitens
tiny bluet Houstonia pusilla
tufted lovegrass Eragrostis pectinacea
twoflower dwarfdandelion Krigia biflora
upright burhead Echinodorus berteroi
upright carrionflower Smilax ecirrhata
variegated scouringrush Equisetum variegatum
violet lespedeza Lespedeza violacea
violet woodsorrel Oxalis violacea
Virginia bunchflower Veratrum virginicum
Virginia groundcherry Physalis virginiana
Virginia mountainmint Pycnanthemum virginianum
Virginia pepperweed Lepidium virginicum
Virginia plantain Plantago virginica
Virginia springbeauty Claytonia virginica
Virginia strawberry Fragaria virginiana
waxyleaf meadow-rue Thalictrum revolutum
western tansymustard Descurainia pinnata
western waterweed Elodea nuttallii
white baneberry Actaea pachypoda
white blue-eyed grass Sisyrinchium albidum
white fawnlily Erythronium albidum
white heath aster Symphyotrichum ericoides
white rattlesnakeroot Prenanthes alba
white snakeroot Ageratina altissima
white trillium Trillium grandiflorum
white vervain Verbena urticifolia
whitehair rosette grass Dichanthelium villosissimum
whitetinge sedge Carex albicans
wholeleaf rosinweed Silphium integrifolium
whorled milkweed Asclepias verticillata
whorled milkwort Polygala verticillata
whorled mountainmint Pycnanthemum verticillatum
widowsfrill Silene stellata
wild yam Dioscorea villosa
willowleaf aster Symphyotrichum praealtum
winged lythrum Lythrum alatum
wingstem Verbesina alternifolia
witchgrass Panicum capillare
woman's tobacco Antennaria plantaginifolia
woodland lettuce Lactuca floridana
yellow giant hyssop Agastache nepetoides
yellow pimpernel Taenidia integerrima
yellowfruit sedge Carex annectens
yellowseed false pimpernel Lindernia dubia

Also listed as native and introduced here 5

PLANTS labels these species both native and introduced in this state: some forms are native and others were brought in from elsewhere. Most gardeners should choose plants from the main list.

annual ragweedAmbrosia artemisiifolia
bride's feathersAruncus dioicus
climbing false buckwheatPolygonum scandens
common reedPhragmites australis
Kentucky bluegrassPoa pratensis

Compared with Illinois

The typical county is the median of the 102 Illinois counties with PLANTS county records; the statewide figure counts every species native anywhere in the state. More species is not better or worse: counties differ in size, habitat and how thoroughly they have been surveyed.

Native species counts, Knox County and Illinois
Measure	Knox County	Typical county	Statewide
Native species	490	641	1,909
Garden-ready natives	217	272	652
Tree	51	—	187
Shrub	15	—	96
Wildflower (forb)	311	—	1,015
Grass or grass-like	80	—	444
Vine	20	—	79
Fern	13	—	88

Neighboring counties

Counties that share a ZIP code with Knox County.

Fulton County, IL 300 garden-ready
Henry County, IL 271 garden-ready
Mercer County, IL 169 garden-ready
Peoria County, IL 367 garden-ready
Stark County, IL 215 garden-ready
Warren County, IL 146 garden-ready

Source & data date

Source: USDA NRCS PLANTS Database: county distribution records, native status and plant characteristics. CC0 (public domain dedication, per the data.gov catalog record).; Kew’s World Checklist of Vascular Plants (WCVP): native or introduced status by state. CC BY 3.0.; USGS US-RIIS (ver. 2.0): species listed as introduced are excluded. CC0.
Citation: USDA, NRCS. 2026. The PLANTS Database (https://plants.usda.gov, 11/04/2026). National Plant Data Team, Greensboro, NC USA.; Govaerts R. (ed.) (2026). WCVP: World Checklist of Vascular Plants. Facilitated by the Royal Botanic Gardens, Kew. Data file dated 2026-06-04, http://sftp.kew.org/pub/data-repositories/WCVP/ (retrieved 2026-11-04). Paper: Govaerts R. et al. (2021) The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. Scientific Data 8, 215.
Data date: Retrieved from PLANTS on November 4, 2026; WCVP data file dated June 4, 2026.
Zones: USDA Plant Hardiness Zone Map (2023) ZIP table: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 3, 2026. Plant zones on this site are our estimate, not the official map.
Scope: Knox County (county FIPS 17095), Illinois. 490 native species from PLANTS county distribution records; garden-ready = species with a PLANTS characteristics record.
Method: A species is listed when it is recorded as native to the state in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in the county by USDA PLANTS. Species PLANTS labels both native and introduced are listed separately. Full method · All sources

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