Bloomipedia
Buttonbush (Cephalanthus occidentalis)
Photo: Ken-ichi Ueda via iNaturalist · CC BY 4.0 · resized

Flower profile

Buttonbush

Cephalanthus occidentalis

Buttonbush (Cephalanthus occidentalis) is a shrub or small tree in the Rubiaceae family, native in the lower 48 states, blooming mostly June–August across the U.S.

Native in the lower 48

Buttonbush is a flowering plant that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 28 states, and across the U.S. it's most often seen in bloom in June–August.

37states where USDA records it
28Bloomipedia state lists include it
63,731U.S. sightings*

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

On our lists for: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Rhode Island, South Carolina, Tennessee, Texas, Virginia

Quick look

Cephalanthus occidentalis is a species of flowering plant in the family Rubiaceae that is native to eastern and southern North America. Common names include buttonbush, common buttonbush, button-willow, buck brush, and honey-bells.

  • It belongs to the Rubiaceae family. iNaturalist
  • USDA PLANTS describes it as a shrub / a tree with a perennial life cycle. USDA PLANTS
  • USDA PLANTS lists it as native in the lower 48 states and records it in 37 states. USDA PLANTS
  • In Texas, most iNaturalist sightings of it in flower come in June–August. iNaturalist
  • In Florida, most iNaturalist sightings of it in flower come in April–July. iNaturalist
  • USDA PLANTS lists its flower color as white. USDA PLANTS
  • USDA PLANTS gives its bloom period as summer. USDA PLANTS
  • USDA PLANTS lists a mature height of about 15 ft. USDA PLANTS
  • iNaturalist has 13,059 research-grade sightings of it in Texas, ranking #39 among the 169 flowers on our Texas list. iNaturalist
  • iNaturalist has 6,675 research-grade sightings of it in Florida, ranking #18 among the 151 flowers on our Florida list. iNaturalist
  • iNaturalist has 3,253 research-grade sightings of it in Massachusetts, ranking #44 among the 188 flowers on our Massachusetts list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (5,064 records)
Bloom time in the 28 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
TexasNativeJune–August13,059
FloridaNativeApril–July6,675
MassachusettsNativeJuly–August3,253
New YorkNativeJuly–August3,170
OhioNativeJuly–August2,999
VirginiaNativeJune–August2,322
MichiganNativeJuly2,073
IllinoisNativeJune–July1,936
North CarolinaNativeJune–August1,908
New JerseyNativeJune–August1,643
MarylandNativeJune–August1,605
IndianaNativeJune–August1,509
LouisianaNativeMay–August1,407
ArkansasNativeJune–August1,398
GeorgiaNativeJune–August1,389
OklahomaNativeJune–August1,336
AlabamaNativeMay–July1,249
TennesseeNativeJune–August1,214
MissouriNativeJune–August1,192
New HampshireNativeJuly–August896
ConnecticutNativeJuly–August882
South CarolinaNativeJune–August766
KentuckyNativeJune–August687
KansasNativefew records (20)562
MississippiNativeJune–August486
IowaNativefew records (24)278
DelawareNativefew records (33)262
Rhode IslandNativefew records (17)237

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
State rare plant lists
Not listed Not on the official rare plant list in 20 of our 28 states.
See each state
Texas
Not listed Not on Texas endangered and threatened plants (31 Tex. Admin. Code § 69.8), as listed by Texas Parks and Wildlife. NatureServe: SNR, not yet ranked in Texas. 31 TAC 69.8
Florida
Not listed Not on Florida Regulated Plant Index (Fla. Admin. Code 5B-40.0055). NatureServe: S5, secure in Florida. FAC 5B-40.0055
Massachusetts
Not listed Not on Massachusetts Endangered Species Act list (321 CMR 10.90). NatureServe: SNR, not yet ranked in Massachusetts. MESA list
New York
Not listed Not on New York protected native plants (6 NYCRR § 193.3). NatureServe: S5, secure in New York. 6 NYCRR § 193.3
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
Virginia
Not listed Not on Virginia endangered and threatened plant and insect species (2VAC5-320-10). NatureServe: S5, secure in Virginia. 2VAC5-320-10
Michigan
Not listed Not on Michigan endangered and threatened plants (Mich. Admin. Code R 299.1028, eff. March 20, 2023). NatureServe: SNR, not yet ranked in Michigan. R 299.1028
Illinois
Not listed Not on Illinois List of Endangered and Threatened Flora (17 Ill. Adm. Code 1050), per the Endangered Species Protection Board's 2025 checklist. NatureServe: SNR, not yet ranked in Illinois. IL E&T checklist 2025
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
New Jersey
Not listed Not on New Jersey Endangered Plant Species List (N.J.A.C. 7:5C-5.1). NatureServe: S5, secure in New Jersey. N.J.A.C. 7:5C-5.1
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
Georgia
Not listed Not on Georgia protected plants (Ga. Comp. R. & Regs. 391-4-10-.09; a 2026 update is proposed). NatureServe: SNR, not yet ranked in Georgia. Ga. R. 391-4-10-.09
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
Missouri
Not listed Not on Missouri Wildlife Code endangered species (3 CSR 10-4.111), plants. NatureServe: SNR, not yet ranked in Missouri. 3 CSR 10-4.111
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
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
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
Iowa
Not listed Not on Iowa endangered, threatened and special concern plants (Iowa Admin. Code r. 571-77.3). NatureServe: S4, apparently secure in Iowa. IAC 571-77.3
Delaware
Not listed Not on Rare and Uncommon Plants of Delaware (DNREC, 2024; informational, Delaware has no state plant-protection list). NatureServe: S5, secure in Delaware. DE rare plants 2024
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
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.
Louisiana
No list Louisiana has no state list of endangered or threatened plants separate from the federal list, so we show federal status and NatureServe's Louisiana ranks. NatureServe: SNR, not yet ranked in Louisiana.
Arkansas
No list Arkansas has no state law listing endangered or threatened plants, so we show NatureServe's Arkansas ranks instead. NatureServe: SNR, not yet ranked in Arkansas.
Oklahoma
No list Oklahoma has no state law listing endangered or threatened plants, so we show NatureServe's Oklahoma ranks instead. NatureServe: SNR, not yet ranked in Oklahoma.
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.
South Carolina
No list South Carolina has no state law listing endangered or threatened plants, so we show NatureServe's South Carolina ranks instead. NatureServe: S5, secure in South Carolina.
Kansas
No list Kansas's endangered and threatened list (K.A.R. 115-15-1) covers animals only, so we show NatureServe's Kansas ranks for plants. NatureServe: SNR, not yet ranked in Kansas.
Mississippi
No list Mississippi has no state law listing endangered or threatened plants, so we show NatureServe's Mississippi ranks instead. NatureServe: SNR, not yet ranked in Mississippi.
Rare elsewhere
No other U.S. state ranks it S1, S2, SH or SX.

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

Can you eat it?

For peoplePoisonous to people

NC State Extension lists it as poisonous to humans (severity: low). Poisonous parts: bark. Symptoms they list: “The toxin is found in the bark. Ingestion of the bark can cause vomiting, convulsions and paralysis.” NC State Extension

For petsCan be a problem for horses

NC State Extension flags it as a problem for horses. It isn't on the ASPCA plant list. NC State Extension

🌿 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 buttonbush in 37 states plus Washington, D.C.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

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

Texas counties with USDA records: Anderson, Angelina, Aransas, Bell, Brazos, Brewster, Brown, Burnet, Cameron, Cass, Chambers, Cherokee, Coleman, Collin, Collingsworth, Colorado, Dallas, Deaf Smith, Denton, Erath, Freestone, Galveston, Gonzales, Gray, Grayson, Gregg, Grimes, Hamilton, Hardin, Harris, Hays, Hemphill, Hidalgo, Houston, Hunt, Hutchinson, Jim Wells, Kenedy, Kinney, Kleberg, Lee, Leon, Llano, Madison, Marion, Mason, Matagorda, McLennan, McMullen, Medina, Menard, Mills, Montgomery, Nacogdoches, Newton, Nueces, Orange, Parker, Polk, Presidio, Randall, Roberts, Robertson, Runnels, Rusk, San Saba, Schleicher, Scurry, Smith, Starr, Swisher, Tarrant, Taylor, Terrell, Tom Green, Travis, Tyler, Upshur, Val Verde, Wheeler, Wichita, Williamson, Wood, Zavala.

Florida counties with USDA records: Alachua, Baker, Brevard, Broward, Calhoun, Charlotte, Citrus, Clay, Collier, Columbia, DeSoto, Dixie, Duval, Flagler, Franklin, Gadsden, Hamilton, Hardee, Hernando, Highlands, Hillsborough, Holmes, Indian River, Jackson, Jefferson, Lafayette, Lake, Lee, Leon, Levy, Liberty, Madison, Manatee, Marion, Martin, Miami-Dade, Monroe, Nassau, Okaloosa, Okeechobee, Orange, Osceola, Palm Beach, Pasco, Pinellas, Polk, Putnam, Sarasota, Seminole, St. Johns, St. Lucie, Sumter, Suwannee, Taylor, Union, Volusia, Wakulla, Walton, Washington.

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

Growing conditions

USDA PLANTS gives Buttonbush a low shade tolerance, medium drought tolerance and high moisture use. It is rated for soil pH 4.7 to 8.6 and winter lows down to -33 °F.

Shade tolerance
Low
Drought tolerance
Medium
Moisture use
High
Soil textures it is adapted to
coarse, medium, fine
Soil pH range
4.7 to 8.6
Minimum temperature tolerated
-33 °F
Frost-free days needed (minimum)
150
Annual precipitation range
20 to 80 inches
Minimum root depth
14 inches
Salinity tolerance
Low
Fertility requirement
Low
Growth rate
Moderate
Lifespan
Short
Active growth period
Spring
Fruit or seed
White · Fall to Fall
Can be propagated by
bare root, container, cuttings, seed
Commercial availability
Routinely Available

From the USDA PLANTS characteristics data for CEOC2. 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 1638 counties across 36 states; the most are in Missouri (111), Kentucky (96), Illinois (94).

More from the Rubiaceae family (18 on Bloomipedia; most observed first): Partridgeberry, Azure bluet, Field madder, Largeflower Mexican clover, Buttonweed, Tiny bluet, Shiny-leaved wild coffee, Diamond-flowers.

More Texas flowers

Field madder (Sherardia arvensis)

Field madder

Sherardia arvensis

Introduced

🌼 Blooms in TX: February–April
Diamond-flowers (Stenaria nigricans)

Diamond-flowers

Stenaria nigricans

Native

🌼 Blooms in TX: April–July
Gardenia (Gardenia jasminoides)

Gardenia

Gardenia jasminoides

🌷 Flowering shrub

🌷 Grown in Texas gardens

Sources