Flower profile

Trailing blackberry

Rubus ursinus

Trailing blackberry (Rubus ursinus) is a low shrub in the Rosaceae family, native in the lower 48 states, blooming mostly March–May across the U.S.

Native in the lower 48

Trailing blackberry is a flowering plant 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–May.

5states where USDA records it

3Bloomipedia state lists include it

28,713U.S. sightings*

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

On our lists for: California, Oregon, Washington

Quick look

Rubus ursinus is a North American species of blackberry or dewberry, known by the common names California blackberry, California dewberry, Douglas berry, Pacific blackberry, Pacific dewberry and trailing blackberry.
From Wikipedia's article Rubus ursinus, CC BY-SA 4.0.

It belongs to the Rosaceae family. ^iNaturalist
USDA PLANTS describes it as a subshrub with a perennial life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as native in the lower 48 states and records it in 5 states. ^{USDA PLANTS}
NatureServe lists it as native to California, Washington and Oregon. ^NatureServe
In California, most iNaturalist sightings of it in flower come in March–May. ^iNaturalist
In Washington, most iNaturalist sightings of it in flower come in April–June. ^iNaturalist
USDA PLANTS lists its flower color as white. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as early spring. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 2 ft. ^{USDA PLANTS}
iNaturalist has 16,594 research-grade sightings of it in California, ranking #38 among the 178 flowers on our California list. ^iNaturalist
iNaturalist has 6,543 research-grade sightings of it in Washington, ranking #15 among the 187 flowers on our Washington list. ^iNaturalist
iNaturalist has 5,488 research-grade sightings of it in Oregon, ranking #13 among the 184 flowers on our Oregon list. ^iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (3,684 records)

Bloom time in the 3 states whose Bloomipedia list includes it

State	Type	Peak bloom	Sightings*
California	Native	March–May	16,594
Washington	Native	April–June	6,543
Oregon	Native	April–May	5,488

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
California: Not listed Not on California state-listed endangered, threatened and rare plants (14 CCR § 670.2), per CDFW's CNDDB list (July 2026). NatureServe: SNR, not yet ranked in California. ^{CNDDB listed plants (July 2026)}
Washington: No list Washington has no state law listing endangered or threatened plants (the Washington Natural Heritage Program's rare plant list isn't regulatory), so we show NatureServe's Washington ranks instead. NatureServe: SNR, not yet ranked in Washington.
Oregon: Not listed Not on Oregon endangered and threatened plants (OAR 603-073-0070). NatureServe: SNR, not yet ranked in Oregon. ^{OAR 603-073-0070}
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. For context only: ASPCA lists a related species, Rubus pedatus (“Creeping Rubus”), as non-toxic to dogs and cats. That doesn't tell us about this species, so keep pets away to be safe. ^ASPCA

🌿 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 trailing blackberry in 5 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

California, Idaho, Montana, Oregon, Washington.

California counties with USDA records: Alameda, Butte, Colusa, Contra Costa, Del Norte, El Dorado, Fresno, Glenn, Humboldt, Kern, Lake, Los Angeles, Marin, Mariposa, Mendocino, Monterey, Napa, Orange, Plumas, Riverside, Sacramento, San Benito, San Bernardino, San Diego, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Shasta, Siskiyou, Solano, Sonoma, Sutter, Tehama, Tulare, Tuolumne, Ventura, Yolo.

Washington counties with USDA records: Chelan, Clallam, Clark, Cowlitz, Grays Harbor, Island, King, Kitsap, Kittitas, Klickitat, Lewis, Mason, Pacific, Pierce, San Juan, Skagit, Skamania, Snohomish, Thurston, Wahkiakum, Walla Walla, Whatcom.

Oregon counties with USDA records: Benton, Clackamas, Clatsop, Coos, Curry, Douglas, Hood River, Jackson, Jefferson, Josephine, Klamath, Lane, Lincoln, Linn, Marion, Multnomah, Polk, Tillamook, Umatilla, Union, Wallowa, Wasco, Washington, Yamhill.

Growing conditions

USDA PLANTS gives Trailing blackberry a high shade tolerance, medium drought tolerance and medium moisture use. It is rated for soil pH 6.0 to 7.5 and winter lows down to 7 °F.

Shade tolerance: High
Drought tolerance: Medium
Moisture use: Medium
Soil textures it is adapted to: coarse, medium, fine
Soil pH range: 6.0 to 7.5
Minimum temperature tolerated: 7 °F
Frost-free days needed (minimum): 190
Annual precipitation range: 14 to 24 inches
Minimum root depth: 14 inches
Salinity tolerance: None
Fertility requirement: Medium
Growth rate: Rapid
Lifespan: Short
Active growth period: Spring and Summer
Fruit or seed: Black · Spring to Summer
Can be propagated by: bare root, container, seed, sprigs
Commercial availability: Contracting Only

From the USDA PLANTS characteristics data for RUUR. 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 92 counties across 4 states; the most are in California (41), Oregon (24), Washington (22).

Other Rubus on Bloomipedia (14): Thimbleberry, Wineberry, Black raspberry, Salmonberry, Southern dewberry, Purple-flowered raspberry, Armenian blackberry, Swamp dewberry, Rocky Mountain raspberry, Five-leaf dwarf bramble.

More from the Rosaceae family (103 on Bloomipedia; most observed first): Roses (genus Rosa), Multiflora rose, Mock strawberry, Black cherry, Toyon, Chokecherry, White meadowsweet, Ocean spray.

More California flowers

Toyon

Heteromeles arbutifolia

Native

🌼 Blooms in CA: June–August

Roses (genus Rosa)

Rosa

★ NY state flower🌷 Garden flower

🌼 Blooms in CA: April–July

Thimbleberry

Rubus parviflorus

Native

🌼 Blooms in CA: April–July

Sources

USDA, NRCS. PLANTS Database, profile RUUR.
iNaturalist, Rubus ursinus: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Rubus ursinus (lead quoted under CC BY-SA 4.0).
California: California state-listed endangered, threatened and rare plants (14 CCR § 670.2), per CDFW's CNDDB list (July 2026).
California: California noxious weed species (3 CCR § 4500).
Washington: Washington State noxious weed list (WAC 16-750-005, -011, -015).
Oregon: Oregon endangered and threatened plants (OAR 603-073-0070).
Oregon: Oregon noxious weed quarantine, A and B weeds (OAR 603-052-1200).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Rubus ursinus (global and state ranks).
Edibility and toxicity: ASPCA.
Photo: carbapple via iNaturalist · CC BY 4.0 · resized.