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Native plants · Iowa

Native plants of Washington County

147 plant species are recorded as native to Iowa in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in Washington County by USDA PLANTS. 63 of them have growing records you can filter by light, moisture, height and estimated cold hardiness. 1 more species is listed as both native and introduced and kept in a separate section.

County summary · USDA PLANTS and Kew WCVP

Washington County, Iowa

Native species
147 Typical Iowa county: 44 (median of 99 counties)
Garden-ready natives
63 Typical Iowa county: 24
Share by type (all 147 native species)
Percent of the 147 native species in each growth type
Tree 8% (12)
Shrub 3% (5)
Wildflower (forb) 67% (99)
Grass or grass-like 14% (20)
Vine 3% (5)
Fern 4% (6)

Wildflowers make up the largest share of the native list (67%), followed by grasses and grass-like plants (14%).

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

Cold hardiness is estimated from each plant’s PLANTS minimum temperature. How we estimate it.

Garden-ready natives 63

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

Garden-ready native plants of Washington County, Iowa
PlantType HeightLight Water useHardy to
American sycamore Platanus occidentalis Tree 100 ft Sun–part shade High Zone 4a
American water horehound Lycopus americanus Wildflower (forb) 1.8 ft Shade-tolerant High Zone 3b
bitternut hickory Carya cordiformis Tree 75 ft Sun Medium Zone 2b
black oak Quercus velutina Tree 80 ft Sun–part shade Medium Zone 4a
blackeyed Susan Rudbeckia hirta Wildflower (forb) 1 ft Sun Medium Zone 5a
bluntleaf bedstraw Galium obtusum Wildflower (forb) 1.5 ft Shade-tolerant High Zone 4a
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
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
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
Carolina foxtail Alopecurus carolinianus Grass or grass-like 1.7 ft Sun Low Zone 3a
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
composite dropseed Sporobolus compositus Grass or grass-like 3 ft Sun Low Zone 3b
coralberry Symphoricarpos orbiculatus Shrub 2 ft Sun–part shade High Zone 5a
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
ditch stonecrop Penthorum sedoides Wildflower (forb) 2.6 ft Sun–part shade Medium Zone 4b
dwarf St. Johnswort Hypericum mutilum Wildflower (forb) 2.6 ft Sun–part shade Medium Zone 5a
fall panicgrass Panicum dichotomiflorum Grass or grass-like 3.3 ft Sun High Zone 3a
false daisy Eclipta prostrata Wildflower (forb) 3.2 ft Sun–part shade Medium Zone 10b
field horsetail Equisetum arvense Fern 11 in Sun–part shade High Zone 3a
fringed brome Bromus ciliatus Grass or grass-like 4 ft Shade-tolerant Medium Zone 7a
fringeleaf wild petunia Ruellia humilis Wildflower (forb) 2.6 ft Shade-tolerant Low Zone 4a
golden tickseed Coreopsis tinctoria Wildflower (forb) 3 ft Sun–part shade High Zone 12b
gray dogwood Cornus racemosa Shrub 10 ft Shade-tolerant Medium Zone 2b
hairy white oldfield aster Symphyotrichum pilosum Wildflower (forb) 3 ft Shade-tolerant Medium Zone 4a
Indiangrass Sorghastrum nutans Grass or grass-like 6 ft Sun Medium Zone 3b
Jack in the pulpit Arisaema triphyllum Wildflower (forb) 1.5 ft Shade-tolerant High Zone 5b
jewelweed Impatiens capensis Wildflower (forb) 4.9 ft Shade-tolerant Medium Zone 10b
narrowleaf blue-eyed grass Sisyrinchium angustifolium Wildflower (forb) 2 ft Sun–part shade Medium Zone 7a
nimblewill Muhlenbergia schreberi Grass or grass-like 3.2 ft Shade-tolerant Low Zone 4a
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
northern maidenhair Adiantum pedatum Fern 1.3 ft Shade-tolerant Medium Zone 3b
Pennsylvania bittercress Cardamine pensylvanica Wildflower (forb) 1.5 ft Shade-tolerant Medium Zone 4a
pinnate prairie coneflower Ratibida pinnata Wildflower (forb) 4 ft Sun Medium Zone 3b
prairie fleabane Erigeron strigosus Wildflower (forb) 3 ft Sun Medium Zone 4b
pride of Ohio Dodecatheon meadia Wildflower (forb) 2 ft Shade-tolerant Medium Zone 3b
purplestem beggarticks Bidens connata Wildflower (forb) 3.2 ft Sun–part shade High Zone 12a
quaking aspen Populus tremuloides Tree 65 ft Sun High Zone 1a
roughleaf dogwood Cornus drummondii Tree 20 ft Sun–part shade Low Zone 4b
sandbar willow Salix interior Tree 30 ft Sun — Zone 1a
sawtooth sunflower Helianthus grosseserratus Wildflower (forb) 5 ft Sun Medium Zone 3a
shagbark hickory Carya ovata Tree 75 ft Sun–part shade Medium Zone 3a
smooth hedgenettle Stachys tenuifolia Wildflower (forb) 25 ft Shade-tolerant High Zone 4a
smooth horsetail Equisetum laevigatum Fern 5 ft Sun Low Zone 3b
strawcolored flatsedge Cyperus strigosus Grass or grass-like 3.2 ft Sun Medium Zone 4a
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
teal lovegrass Eragrostis hypnoides Grass or grass-like 4 in Sun High Zone 3b
threelobe beggarticks Bidens tripartita Wildflower (forb) 3.5 ft Sun–part shade High Zone 12a
upland bentgrass Agrostis perennans Grass or grass-like 3.5 ft Sun–part shade 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 meadowsweet Spiraea alba Shrub 3 ft Sun–part shade Medium Zone 4a
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 sarsaparilla Aralia nudicaulis Wildflower (forb) 1.5 ft Shade-tolerant Medium Zone 3b
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

Other native species recorded here 84

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 false pennyroyal Hedeoma pulegioides
  • American lopseed Phryma leptostachya
  • big devils beggartick Bidens vulgata
  • bigbract verbena Verbena bracteata
  • bloodroot Sanguinaria canadensis
  • blue skullcap Scutellaria lateriflora
  • bluntleaf sandwort Moehringia lateriflora
  • bog yellowcress Rorippa palustris
  • Canada lettuce Lactuca canadensis
  • Canadian blacksnakeroot Sanicula canadensis
  • Canadian clearweed Pilea pumila
  • Canadian wildginger Asarum canadense
  • Canadian woodnettle Laportea canadensis
  • Carolina horsenettle Solanum carolinense
  • carpenter's square Scrophularia marilandica
  • Christmas fern Polystichum acrostichoides
  • clasping Venus' looking-glass Triodanis perfoliata
  • common boneset Eupatorium perfoliatum
  • common pricklyash Zanthoxylum americanum
  • common threeseed mercury Acalypha rhomboidea
  • common yellow oxalis Oxalis stricta
  • cutleaf grapefern Botrychium dissectum
  • cutleaf toothwort Cardamine concatenata
  • downy hawthorn Crataegus mollis
  • dutchman's breeches Dicentra cucullaria
  • eastern daisy fleabane Erigeron annuus
  • eastern false rue anemone Enemion biternatum
  • fall witchgrass Digitaria cognata
  • forked threeawn Aristida basiramea
  • fragrant bedstraw Galium triflorum
  • fringed loosestrife Lysimachia ciliata
  • great blue lobelia Lobelia siphilitica
  • great ragweed Ambrosia trifida
  • green carpetweed Mollugo verticillata
  • hairy hedgenettle Stachys pilosa
  • heartleaf four o'clock Mirabilis nyctaginea
  • hedge false bindweed Calystegia sepium
  • hemlock waterparsnip Sium suave
  • hoary frostweed Helianthemum bicknellii
  • hoary puccoon Lithospermum canescens
  • Indian-tobacco Lobelia inflata
  • lanceleaf fogfruit Phyla lanceolata
  • Mexican plum Prunus mexicana
  • New England aster Symphyotrichum novae-angliae
  • oneseed bur cucumber Sicyos angulatus
  • palespike lobelia Lobelia spicata
  • prairie blue-eyed grass Sisyrinchium campestre
  • prairie groundsel Packera plattensis
  • prairie sunflower Helianthus petiolaris
  • prairie threeawn Aristida oligantha
  • purple meadow-rue Thalictrum dasycarpum
  • purple milkwort Polygala sanguinea
  • rabbit-tobacco Pseudognaphalium obtusifolium
  • red columbine Aquilegia canadensis
  • ribseed sandmat Chamaesyce glyptosperma
  • rough barnyardgrass Echinochloa muricata
  • roundseed St. Johnswort Hypericum sphaerocarpum
  • rue anemone Thalictrum thalictroides
  • sensitive fern Onoclea sensibilis
  • silky dogwood Cornus obliqua
  • skyblue aster Symphyotrichum oolentangiense
  • sleepy silene Silene antirrhina
  • smooth rose Rosa blanda
  • spotted sandmat Chamaesyce maculata
  • spotted water hemlock Cicuta maculata
  • swamp dock Rumex verticillatus
  • swamp verbena Verbena hastata
  • tall thoroughwort Eupatorium altissimum
  • tall tickseed Coreopsis tripteris
  • toothed spurge Euphorbia dentata
  • violet woodsorrel Oxalis violacea
  • Virginia springbeauty Claytonia virginica
  • Virginia strawberry Fragaria virginiana
  • white snakeroot Ageratina altissima
  • wholeleaf rosinweed Silphium integrifolium
  • whorled milkweed Asclepias verticillata
  • wild yam Dioscorea villosa
  • winged lythrum Lythrum alatum
  • wingstem Verbesina alternifolia
  • witchgrass Panicum capillare
  • woodland lettuce Lactuca floridana
  • yellowseed false pimpernel Lindernia dubia
Also listed as native and introduced here 1

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

Compared with Iowa

The typical county is the median of the 99 Iowa 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, Washington County and Iowa
MeasureWashington CountyTypical countyStatewide
Native species 147 44 1,374
Garden-ready natives 63 24 496
Tree 12 — 110
Shrub 5 — 72
Wildflower (forb) 99 — 779
Grass or grass-like 20 — 298
Vine 5 — 55
Fern 6 — 60

Neighboring counties

Counties that share a ZIP code with Washington County.

Look up another ZIP

Matches your ZIP to the county it mostly lies in, then lists the plants recorded as native to your state (Kew’s World Checklist and USDA PLANTS) and recorded in that county by USDA PLANTS.

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
Washington County (county FIPS 19183), Iowa. 147 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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