Flower profile

Tall jacob's-ladder

Polemonium acutiflorum

Tall jacob's-ladder (Polemonium acutiflorum) is a flowering plant in the Polemoniaceae family, blooming mostly June–August across the U.S.

Native to Alaska

Tall jacob's-ladder is a wildflower. In Alaska it's most often seen in bloom in June–August.

1states where USDA records it

816AK sightings*

816U.S. sightings*

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

On our lists for: Alaska

Quick look

Polemonium acutiflorum, known as tall Jacob's-ladder, is a flowering plant in the family Polemoniaceae. It is native to much of the northern hemisphere.
From Wikipedia's article Polemonium acutiflorum, CC BY-SA 4.0.

It belongs to the Polemoniaceae family. ^iNaturalist
USDA PLANTS describes it as an herb (forb) with a perennial life cycle. ^{USDA PLANTS}
NatureServe lists it as native to Alaska. ^NatureServe
In Alaska, most iNaturalist sightings of it in flower come in June–August. ^iNaturalist
USDA PLANTS lists its flower color as blue. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as summer. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 3 ft. ^{USDA PLANTS}
iNaturalist has 816 research-grade sightings of it in Alaska, ranking #52 among the 121 flowers on our Alaska list. ^iNaturalist

When does it bloom?

In Alaska, most flowering sightings come in June–August.

Flowering records by month in Alaska (iNaturalist research-grade observations marked “Flowering”) (69 records)

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
Alaska: No list Alaska has no state law listing endangered or threatened plants, so we show NatureServe's Alaska ranks instead. NatureServe: SNR, not yet ranked in Alaska.
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 tall jacob's-ladder in 1 states.

AKMEVTNHWAIDMTNDMNILWIMINYRIMAORNVWYSDIAINOHPANJCTCAUTCONEMOKYWVVAMDDEAZNMKSARTNNCSCDCOKLAMSALGAHITXFL

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alaska.

Alaska counties with USDA records: Aleutians East, Aleutians West, Anchorage, Bethel, Bristol Bay, Chugach, Copper River, Denali, Dillingham, Fairbanks North Star, Haines, Juneau, Kenai Peninsula, Kodiak Island, Lake and Peninsula, Matanuska-Susitna, Nome, North Slope, Northwest Arctic, Southeast Fairbanks, Yakutat, Yukon-Koyukuk.

Growing conditions

USDA PLANTS gives Tall jacob's-ladder a low shade tolerance and none drought tolerance. It is rated for soil pH 5.0 to 7.8 and winter lows down to -62 °F.

Shade tolerance: Low
Drought tolerance: None
Soil textures it is adapted to: coarse, medium
Soil pH range: 5.0 to 7.8
Minimum temperature tolerated: -62 °F
Frost-free days needed (minimum): 47
Annual precipitation range: 9 to 276 inches
Minimum root depth: 12 inches
Salinity tolerance: None
Fertility requirement: Medium
Growth rate: Rapid
Lifespan: Short
Active growth period: Spring
Fruit or seed: · Spring to Fall
Can be propagated by: bare root, container, cuttings, seed
Commercial availability: Routinely Available

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

Names, range and relatives

Native status by region (USDA PLANTS): Alaska: Native; Canada: Native.

County records: USDA PLANTS lists it in 22 counties across 1 states; the most are in Alaska (22).

Other Polemonium on Bloomipedia (2): Jacob's ladder, Sky pilot.

More from the Polemoniaceae family (14 on Bloomipedia; most observed first): Blue phlox, Scarlet gilia, Fall phlox, Prairie phlox, Grand collomia, Longleaf phlox, Spiny phlox, Narrow-leaf mountain trumpet.

More Alaska flowers

Fireweed

Chamaenerion angustifolium

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🌼 Blooms in AK: July–August

Common cowparsnip

Heracleum maximum

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🌼 Blooms in AK: June–July

Common yarrow

Achillea millefolium

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🌼 Blooms in AK: June–September

Sources

USDA, NRCS. PLANTS Database, profile POAC.
iNaturalist, Polemonium acutiflorum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Polemonium acutiflorum (lead quoted under CC BY-SA 4.0).
Alaska: Alaska prohibited and restricted noxious weeds (11 AAC 34.020).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Polemonium acutiflorum (global and state ranks).
Edibility and toxicity: no source found (marked "not well documented").
Photo: steve b via iNaturalist · CC0 · resized.