Bloomipedia
Ballhead waterleaf (Hydrophyllum capitatum)
Photo: mefisher via iNaturalist · CC0 · resized

Flower profile

Ballhead waterleaf

Hydrophyllum capitatum

Ballhead waterleaf (Hydrophyllum capitatum) is a flowering plant in the Boraginaceae family, native in the lower 48 states, blooming mostly April–June across the U.S.

Native in the lower 48

Ballhead waterleaf is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 2 states, and across the U.S. it's most often seen in bloom in April–June.

9states where USDA records it
2Bloomipedia state lists include it
4,755U.S. sightings*

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

On our lists for: Idaho, Wyoming

Quick look

Hydrophyllum capitatum, is a species of waterleaf known by the common name ballhead waterleaf. It is native to Western North America from British Columbia to Utah.

  • It belongs to the Boraginaceae 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 9 states. USDA PLANTS
  • NatureServe lists it as native to Idaho and Wyoming. NatureServe
  • In Wyoming, most iNaturalist sightings of it in flower come in May–June. 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 819 research-grade sightings of it in Idaho, ranking #30 among the 143 flowers on our Idaho list. iNaturalist
  • iNaturalist has 363 research-grade sightings of it in Wyoming, ranking #78 among the 113 flowers on our Wyoming list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (716 records)
Bloom time in the 2 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
IdahoNativefew records (23)819
WyomingNativeMay–June363

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
Idaho
No list Idaho has no state law listing endangered or threatened plants, so we show NatureServe's Idaho ranks instead. NatureServe: SNR, not yet ranked in Idaho.
Wyoming
No list Wyoming has no state law listing endangered or threatened plants, so we show NatureServe's Wyoming ranks instead. NatureServe: S4, apparently secure in Wyoming.
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 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 ballhead waterleaf in 9 states.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington, Wyoming.

Idaho counties with USDA records: Ada, Adams, Bannock, Benewah, Blaine, Boise, Bonner, Bonneville, Butte, Caribou, Cassia, Clark, Clearwater, Custer, Elmore, Franklin, Fremont, Gem, Gooding, Idaho, Kootenai, Latah, Lemhi, Lincoln, Nez Perce, Oneida, Owyhee, Power, Twin Falls, Valley, Washington.

Wyoming counties with USDA records: Carbon, Fremont, Lincoln, Natrona, Park, Sublette, Teton, Uinta.

Growing conditions

USDA PLANTS gives Ballhead waterleaf a low shade tolerance, low drought tolerance and high moisture use. It is rated for soil pH 6.4 to 7.8 and winter lows down to -28 °F.

Shade tolerance
Low
Drought tolerance
Low
Moisture use
High
Soil textures it is adapted to
medium, fine
Soil pH range
6.4 to 7.8
Minimum temperature tolerated
-28 °F
Frost-free days needed (minimum)
110
Annual precipitation range
16 to 30 inches
Minimum root depth
10 inches
Salinity tolerance
None
Fertility requirement
Medium
Growth rate
Rapid
Lifespan
Moderate
Active growth period
Spring
Fruit or seed
· Spring to Spring
Can be propagated by
seed
Commercial availability
Contracting Only

From the USDA PLANTS characteristics data for HYCA4. 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 131 counties across 9 states; the most are in Idaho (31), Oregon (21), Utah (19).

Other Hydrophyllum on Bloomipedia (3): Virginia waterleaf, Great waterleaf, Pacific waterleaf.

More from the Boraginaceae family (42 on Bloomipedia; most observed first): Virginia bluebells, Pacific hound's tongue, Distant phacelia, Alkali heliotrope, Virginia stickseed, Wild comfrey, Menzies' baby blue eyes, California yerba santa.

More Idaho flowers

Hound's-tongue (Cynoglossum officinale)

Hound's-tongue

Cynoglossum officinale

Introduced

🌼 Few flowering records in ID
Great mullein (Verbascum thapsus)

Great mullein

Verbascum thapsus

Introduced

🌼 Few flowering records in ID
Showy milkweed (Asclepias speciosa)

Showy milkweed

Asclepias speciosa

Native

🌼 Blooms in ID: June–July

Sources