Bloomipedia
Purple cress (Cardamine douglassii)
Photo: Patricia Pennington via iNaturalist · CC BY 4.0 · resized

Flower profile

Purple cress

Cardamine douglassii

Purple cress (Cardamine douglassii) is a flowering plant in the Brassicaceae family, native in the lower 48 states, blooming mostly March–April across the U.S.

Native in the lower 48

Purple cress is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 3 states, and across the U.S. it's most often seen in bloom in March–April.

22states where USDA records it
3Bloomipedia state lists include it
7,181U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Indiana, Kentucky, Ohio

Quick look

Cardamine douglassii, the limestone bittercress or purple cress, is a perennial forb that produces white to pink or purple flowers in early spring. It is native to Ontario, Canada, as well as the eastern and central United States.

  • It belongs to the Brassicaceae family. iNaturalist
  • USDA PLANTS describes it as an herb (forb) with a perennial life cycle. USDA PLANTS
  • USDA PLANTS lists it as native in the lower 48 states and records it in 22 states. USDA PLANTS
  • NatureServe lists it as native to Ohio, Indiana and Kentucky. NatureServe
  • In Ohio, most iNaturalist sightings of it in flower come in March–April. iNaturalist
  • In Indiana, most iNaturalist sightings of it in flower come in March–April. iNaturalist
  • USDA PLANTS lists its flower color as purple. USDA PLANTS
  • USDA PLANTS gives its bloom period as early spring. USDA PLANTS
  • USDA PLANTS lists a mature height of about 1 ft. USDA PLANTS
  • iNaturalist has 2,679 research-grade sightings of it in Ohio, ranking #64 among the 186 flowers on our Ohio list. iNaturalist
  • iNaturalist has 1,040 research-grade sightings of it in Indiana, ranking #77 among the 173 flowers on our Indiana list. iNaturalist
  • iNaturalist has 669 research-grade sightings of it in Kentucky, ranking #95 among the 178 flowers on our Kentucky list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (1,233 records)
Bloom time in the 3 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
OhioNativeMarch–April2,679
IndianaNativeMarch–April1,040
KentuckyNativeFebruary–March669

Conservation status

Federal (U.S. ESA)
Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
NatureServe global
G5 Secure worldwide. NatureServe
Ohio
Not listed Not on Ohio endangered and threatened plants (Ohio Adm. Code 1501:18-1-03, eff. Dec. 26, 2024). NatureServe: SNR, not yet ranked in Ohio. OAC 1501:18-1-03
Indiana
No list Indiana has no state law listing endangered or threatened plants (the DNR keeps a rare plant list, but it isn't regulatory), so we show NatureServe's Indiana ranks instead. NatureServe: S5, secure in Indiana.
Kentucky
Not listed Not on Kentucky endangered and threatened plant lists (400 KAR 3:040, eff. 2026). NatureServe: S5, secure in Kentucky. 400 KAR 3:040
Rare elsewhere
Other states where NatureServe ranks it rare or missing: AL (S2), AR (S1), CT (S2), MA (S1), MN (S1), NC (S2), NJ (S2). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peopleNot well documented

None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.

For petsNot well documented

It isn't on the ASPCA plant list.

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records purple cress in 22 states plus Washington, D.C.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Arkansas, Connecticut, Illinois, Indiana, Iowa, Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, Wisconsin; District of Columbia.

Ohio counties with USDA records: Adams, Ashland, Ashtabula, Athens, Auglaize, Belmont, Brown, Butler, Carroll, Champaign, Clark, Clermont, Clinton, Columbiana, Coshocton, Crawford, Cuyahoga, Darke, Delaware, Erie, Fairfield, Franklin, Gallia, Geauga, Greene, Guernsey, Hamilton, Hancock, Hardin, Harrison, Highland, Hocking, Holmes, Huron, Jackson, Jefferson, Knox, Lake, Lawrence, Licking, Logan, Lorain, Lucas, Madison, Mahoning, Marion, Medina, Meigs, Miami, Monroe, Montgomery, Morgan, Morrow, Muskingum, Noble, Ottawa, Paulding, Perry, Pickaway, Pike, Portage, Preble, Putnam, Richland, Sandusky, Scioto, Seneca, Stark, Summit, Trumbull, Tuscarawas, Van Wert, Vinton, Warren, Washington, Wayne, Williams, Wood, Wyandot.

Indiana counties with USDA records: Allen, Blackford, Boone, Clark, Clinton, Daviess, Delaware, Elkhart, Fayette, Fountain, Fulton, Hamilton, Hancock, Harrison, Hendricks, Howard, Huntington, Jackson, Jay, Jefferson, Johnson, Knox, LaPorte, Lawrence, Madison, Marion, Monroe, Montgomery, Morgan, Newton, Noble, Ohio, Owen, Parke, Perry, Porter, Posey, Putnam, Randolph, St. Joseph, Sullivan, Tippecanoe, Vermillion, Vigo, Wayne, Wells.

Kentucky counties with USDA records: Allen, Anderson, Barren, Bath, Boone, Bourbon, Breckinridge, Bullitt, Caldwell, Campbell, Carroll, Carter, Casey, Clark, Crittenden, Elliott, Fayette, Fleming, Floyd, Franklin, Garrard, Hardin, Henry, Jefferson, Jessamine, Kenton, Larue, Lewis, Livingston, Logan, Madison, Marion, Mason, Meade, Menifee, Mercer, Metcalfe, Monroe, Nelson, Nicholas, Oldham, Owen, Powell, Robertson, Rowan, Trimble, Warren, Woodford.

Growing conditions

USDA PLANTS gives Purple cress a low shade tolerance, none drought tolerance and high moisture use. It is rated for soil pH 6.0 to 7.7 and winter lows down to -33 °F.

Shade tolerance
Low
Drought tolerance
None
Moisture use
High
Soil textures it is adapted to
coarse, medium, fine
Soil pH range
6.0 to 7.7
Minimum temperature tolerated
-33 °F
Frost-free days needed (minimum)
130
Annual precipitation range
24 to 55 inches
Minimum root depth
10 inches
Salinity tolerance
None
Fertility requirement
High
Growth rate
Moderate
Lifespan
Moderate
Active growth period
Spring and Summer
Fruit or seed
Brown · Spring to Spring
Can be propagated by
seed, sprigs
Commercial availability
No Known Source

From the USDA PLANTS characteristics data for CADO. USDA ratings are general guidance for the species, not a guarantee for your garden.

Names, range and relatives

Native status by region (USDA PLANTS): Canada: Native; Lower 48 states: Native.

County records: USDA PLANTS lists it in 347 counties across 18 states; the most are in Ohio (79), Kentucky (48), Indiana (46).

Other Cardamine on Bloomipedia (5): Cut-leaved toothwort, Milkmaids, Two-leaved toothwort, Narrow-leaved bittercress, Nuttall's toothwort.

More from the Brassicaceae family (24 on Bloomipedia; most observed first): Garlic mustard, Dame's rocket, Wild radish, Annual honesty, Western wallflower, Hoary alyssum, European searocket, Bitter wintercress.

More Ohio flowers

Garlic mustard (Alliaria petiolata)

Garlic mustard

Alliaria petiolata

Introduced

🌼 Blooms in OH: April–May
Cut-leaved toothwort (Cardamine concatenata)

Cut-leaved toothwort

Cardamine concatenata

Native

🌼 Blooms in OH: March–April
Dame's rocket (Hesperis matronalis)

Dame's rocket

Hesperis matronalis

Introduced

🌼 Blooms in OH: May–June

Sources