Flower profile

Azure bluet

Houstonia caerulea

Native in the lower 48

Azure bluet is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 15 states, and across the U.S. it's most often seen in bloom in March–June.

28states

15of our state lists

35,576U.S. sightings*

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

On our lists for: Alabama, Connecticut, Kentucky, Maine, Maryland, Massachusetts, New Hampshire, North Carolina, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont, Virginia, West Virginia

Quick look

Houstonia caerulea, commonly known as azure bluet, Quaker ladies, or bluets, is a perennial species in the family Rubiaceae. It is native to eastern Canada and the eastern United States. It is found in a variety of habitats such as cliffs, alpine zones, forests, meadows and shores of rivers or lakes.
From Wikipedia's article Houstonia caerulea, CC BY-SA 4.0.

It belongs to the Rubiaceae 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 28 states. ^{USDA PLANTS}
In Massachusetts, most iNaturalist sightings of it in flower come in April–June. ^iNaturalist
In Pennsylvania, most iNaturalist sightings of it in flower come in April–June. ^iNaturalist
iNaturalist has 4,041 research-grade sightings of it in Massachusetts, ranking #34 among the 110 flowers on our Massachusetts list. ^iNaturalist
iNaturalist has 3,690 research-grade sightings of it in Pennsylvania, ranking #52 among the 111 flowers on our Pennsylvania list. ^iNaturalist
iNaturalist has 3,670 research-grade sightings of it in Virginia, ranking #43 among the 110 flowers on our Virginia list. ^iNaturalist

Azure bluet gift ideas

Handmade azure bluet gifts from independent makers.

🌱 Sample spot. Handmade gift picks from independent shops will appear here once our shop partnership is approved. These cards are placeholders, not real products.

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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (13,215 records)

Bloom time in each of our 15 states

State	Type	Peak bloom	Sightings*
Massachusetts	Native	April–June	4,041
Pennsylvania	Native	April–June	3,690
Virginia	Native	March–May	3,670
North Carolina	Native	March–May	3,062
Ohio	Native	April–May	2,948
New Hampshire	Native	April–June	2,451
Maine	Native	April–June	2,357
Maryland	Native	April–June	1,970
Connecticut	Native	April–June	1,774
Vermont	Introduced	April–June	1,658
Tennessee	Native	March–May	1,240
Kentucky	Native	March–May	1,178
West Virginia	Native	March–June	781
Alabama	Native	February–May	711
Rhode Island	Native	April–June	423

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
Massachusetts: Not listed Not on Massachusetts Endangered Species Act list (321 CMR 10.90). NatureServe: SNR, not yet ranked in Massachusetts. ^{MESA list}
Pennsylvania: Not listed Not on Pennsylvania classified native plants (17 Pa. Code Ch. 45, Subchapter B, as amended 2023). NatureServe: S5, secure in Pennsylvania. ^{17 Pa. Code Ch. 45}
Virginia: Not listed Not on Virginia endangered and threatened plant and insect species (2VAC5-320-10). NatureServe: S5, secure in Virginia. ^2VAC5-320-10
North Carolina: Not listed Not on North Carolina Protected Plant Species List (02 NCAC 48F .0301). NatureServe: S5, secure in North Carolina. ^{02 NCAC 48F .0301}
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}
New Hampshire: Not listed Not on New Hampshire Official Rare Plants List (Ncr 312, eff. Jan 1, 2020). NatureServe: SNR, not yet ranked in New Hampshire. ^{NH Ncr 312}
Maine: Not listed Not on Maine Rare Plant List (Maine Natural Areas Program, 2021). E and T are Maine's official endangered and threatened plants (12 M.R.S.); SC and PE are tracking categories. NatureServe: SNR, not yet ranked in Maine. ^{Maine rare plant list}
Maryland: Not listed Not on Maryland threatened and endangered plants (COMAR 08.03.08.05, .06 and .08). NatureServe: SNR, not yet ranked in Maryland. ^{COMAR 08.03.08}
Connecticut: Not listed Not on Connecticut Endangered, Threatened and Special Concern Plants (RCSA 26-306; 2015 list). NatureServe: SNR, not yet ranked in Connecticut. ^{CT E/T/SC list}
Vermont: Not listed Not on Endangered and Threatened Plants of Vermont (10 V.S.A. chap. 123; list of Feb 10, 2022). NatureServe: SNA, not applicable (usually because it isn't native there) in Vermont. ^{Vermont E&T list}
Tennessee: Not listed Not on Tennessee endangered plants (Tenn. Comp. R. & Regs. 0400-06-02-.04, Rare Plant Protection and Conservation Act). NatureServe: SNR, not yet ranked in Tennessee. ^{TN rule 0400-06-02-.04}
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}
West Virginia: No list West Virginia has no state law listing endangered or threatened plants (only federally listed species are protected), so we show NatureServe's West Virginia ranks instead. NatureServe: S5, secure in West Virginia.
Alabama: No list Alabama has no state law listing endangered or threatened plants, so we show NatureServe's Alabama ranks instead. NatureServe: SNR, not yet ranked in Alabama.
Rhode Island: Not listed Not on Rhode Island Rare Plants 2016 (RI Natural History Survey, from the RI Wildlife Action Plan; informational, Rhode Island has no state plant-protection listing law). NatureServe: SNR, not yet ranked in Rhode Island. ^{RI rare plants 2016}
Rare elsewhere: Other states where NatureServe ranks it rare or missing: MI (S1), WI (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 edibility or poison notes on its page), USDA PLANTS) say whether it's edible or poisonous for people. ^{NC State Extension}

For petsNot well documented

It isn't on the ASPCA plant list, and NC State Extension doesn't flag it for pets.

🌿 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 azure bluet in 28 states plus Washington, D.C.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Arkansas, Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia, West Virginia, Wisconsin; District of Columbia.

Massachusetts counties with USDA records: Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Hampshire, Middlesex, Nantucket, Norfolk, Plymouth, Suffolk, Worcester.

Pennsylvania counties with USDA records: Adams, Allegheny, Armstrong, Beaver, Bedford, Berks, Blair, Bucks, Butler, Cambria, Cameron, Carbon, Centre, Chester, Clarion, Clearfield, Clinton, Columbia, Crawford, Cumberland, Dauphin, Delaware, Elk, Fayette, Forest, Franklin, Fulton, Greene, Huntingdon, Indiana, Jefferson, Juniata, Lackawanna, Lancaster, Lawrence, Lebanon, Lehigh, Luzerne, Lycoming, McKean, Mercer, Mifflin, Monroe, Montgomery, Northampton, Northumberland, Perry, Philadelphia, Pike, Schuylkill, Snyder, Somerset, Sullivan, Susquehanna, Tioga, Union, Venango, Warren, Washington, Wayne, Westmoreland, Wyoming, York.

Virginia counties with USDA records: Accomack, Albemarle, Amelia, Amherst, Appomattox, Arlington, Augusta, Bath, Bedford, Bland, Botetourt, Brunswick, Buckingham, Campbell, Caroline, Carroll, Charles City, Charlotte, Chesapeake , Chesterfield, Craig, Culpeper, Cumberland, Dickenson, Dinwiddie, Essex, Fairfax, Fauquier, Floyd, Fluvanna, Franklin, Frederick, Giles, Gloucester, Goochland, Grayson, Greene, Greensville, Halifax, Hampton , Hanover, Henrico, Henry, Highland, Isle of Wight, James City, King George, King William, King and Queen, Lancaster, Loudoun, Louisa, Lunenburg, Madison, Mathews, Mecklenburg, Middlesex, Montgomery, Nelson, New Kent, Newport News , Northumberland, Nottoway, Orange, Page, Patrick, Powhatan, Prince Edward, Prince George, Prince William, Pulaski, Rappahannock, Richmond, Roanoke, Rockingham, Scott, Shenandoah, Southampton, Spotsylvania, Stafford, Suffolk , Surry, Sussex, Tazewell, Virginia Beach , Warren, Washington, Westmoreland, Wise, York.