Polemonium Species, Jacob's Ladder

Polemonium caeruleum

Family: Polemoniaceae (po-le-moh-nee-AY-see-ee) (Info)
Genus: Polemonium (po-le-MOH-nee-um) (Info)
Species: caeruleum (see-ROO-lee-um) (Info)
Synonym:Polemonium laxiflorum
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Water Requirements:

Requires consistently moist soil; do not let dry out between waterings

Sun Exposure:

Light Shade

Partial to Full Shade

Full Shade



Foliage Color:

Unknown - Tell us


12-18 in. (30-45 cm)

18-24 in. (45-60 cm)

24-36 in. (60-90 cm)


12-15 in. (30-38 cm)


USDA Zone 3a: to -39.9 C (-40 F)

USDA Zone 3b: to -37.2 C (-35 F)

USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

Where to Grow:

Unknown - Tell us



Bloom Color:

Dark Blue

Medium Purple

White/Near White

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Other details:

Unknown - Tell us

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:


Propagation Methods:

By dividing the rootball

From seed; sow indoors before last frost

From seed; direct sow after last frost

Seed Collecting:

Bag seedheads to capture ripening seed

Wear gloves to protect hands when handling seeds

Properly cleaned, seed can be successfully stored


This plant has been said to grow in the following regions:


Anchorage, Alaska (2 reports)

Bigelow, Arkansas

Salinas, California

Washington, District Of Columbia

Cordele, Georgia

Galva, Illinois

Peoria, Illinois

Fishers, Indiana

Indianapolis, Indiana

Jeffersonville, Indiana

Gaithersburg, Maryland

Wellesley Hills, Massachusetts

Battle Creek, Michigan

Owosso, Michigan

Saginaw, Michigan

Hopkins, Minnesota

Osseo, Minnesota

Forsyth, Missouri

Piedmont, Missouri

Auburn, New Hampshire

Manchester, New Hampshire

Merrimack, New Hampshire

Egg Harbor Township, New Jersey

Chama, New Mexico

Alden, New York

Nineveh, New York

West Islip, New York

West Kill, New York

Pembina, North Dakota

Akron, Ohio

Cincinnati, Ohio

Wren, Ohio

Mount Hood Parkdale, Oregon

Portland, Oregon

Bellefonte, Pennsylvania

Chalfont, Pennsylvania

Lancaster, Pennsylvania

Philadelphia, Pennsylvania

Summerville, South Carolina

Knoxville, Tennessee

Viola, Tennessee

Montpelier, Vermont

Chimacum, Washington

Kalama, Washington

Langley, Washington

Olympia, Washington

Poulsbo, Washington

Ellsworth, Wisconsin

Casper, Wyoming

show all

Gardeners' Notes:


On May 6, 2016, konniee from Chama, NM wrote:

Grows easily and self-sows in heavy clay soil beneath a Ponderosa Pine (there is a layer of peaty soil on top from the pine needles). One of the few plants I can grow there in our high-altitude shade (some filtered sun).


On Jul 16, 2012, velmansia from Antioch, TN wrote:

I also have tried growing this plant in TN with no success. 3 times I have tried growing this plant and they have all died.


On Jun 7, 2012, ms_greenjeans from Hopkins, MN (Zone 4a) wrote:

I started with two of these, planted on the east side of my yard and shaded by a large shrub, and I have totally neglected them. They grow quite tall in my clay soil, have come back five years in a row, and they bloom nicely. If I cut the flower stalks off, they rebloom sometimes two or three times a summer. I have divided the original two plants and purchased a couple more. No reseeding at all (I rather wish they would). I love the lush ferny foliage.


On May 12, 2010, wendymadre from Petersburg, VA wrote:

In my Zone 7a garden, in Petersburg, Virginia, I have had this plant fail several times, in both solid and variegated leaf. I don't know if it's the plant, or me (I feel guilty giving our experience a negative rating). It could be that it does not like the prolonged heat and humidity of our summers, but I don't remember if it survived long enough to even experience them. I will try it again (when I have some money to throw away) next to the Solomon's seal, or where I have some epimedium and thalictrum thriving. It may be that I have amended the soil enough in those places that it will survive now. I can't say that I've noticed it around here in other people's yards.


On May 6, 2010, akcrafter from Philadelphia, PA wrote:

I grew this plant in Anchorage, Alaska, where it seeded aggressively. Pretty plant with hosta, yarrow and ferns, but I grew to hate it there because it was so hard to control. My soil was moist and peaty which it clearly adored. I impulsively bought a variegated form and it did not seem as aggressive. My plants were about two feet in height and nicely full. They liked the light shade offered by the taller ferns and yarrow around them.

I am now trying it out in Philadelphia, PA in virtually the same soil and plant combination, but with a dramatic difference in climate. I've already discovered how easy things reseed here so I know that I will have to grab those seed heads before they fill my yard with plantlets.


On Mar 19, 2010, burkgrow from Lancaster, PA wrote:

I agree that this plant can be a tough one to grow. I had no success growing it in clay soil. It just stayed small and some died. I moved the remaining one to a well drained rich soiled sight and it has flourished.


On Jun 5, 2008, trioadastra from Woodbury, MN (Zone 4a) wrote:

I grew two of these from seed. One didn't survive the summer in my clay soil, the other returned this spring with a vengence! I thought it was a 2 to 3 footer, but mine has reached 4 feet tall! I'm waiting for it to stop flowering so I can cut it back. -Update- I cut it back to 12", but left some seedpods, and it is flowering again- mid July.


On Oct 1, 2007, mbhoakct76 from Winsted, CT wrote:

Mine barely seems to survive but has come back 2 yrs in zone 6.
Even when it was healthy- the flowers are very small and not very showy, Personally i find the foliage to be quite ugly and resemble a weed.
Not a easy grower!


On Jun 13, 2006, Gabrielle from (Zone 5a) wrote:

I love the plant, but every one I've had died.


On May 27, 2006, rossmullion from Wolverhampton,
United Kingdom wrote:

This plant grows well in semi shade. The plant I have is a self setter. I have no idea where it came from. It stands erect and has a height of 1 metre. It is very showy and the flowers are light blue in colour. It is growing beside astilbes, clematis and hydrangeas. It obviously enjoys a well watered spot.


On May 26, 2006, fluffygrue from Manchester,
United Kingdom (Zone 8a) wrote:

Lovely plant - we have this growing in moist, not well drained, clayish soil next to a Brunnera, and they're both thriving. And it's not pestered by snails/slugs, which is a bonus.


On Jul 14, 2005, elfmom from Bigelow, AR wrote:

I bought one plant in early spring and it grew well for several months until the southern summer began. In spite of being planted in light shade, well mulched, and watered often, the plant died. However, I liked the plant enough that I am going to try again!


On Apr 30, 2005, ccwales from Wales, MA (Zone 6a) wrote:

This plant loves my garden -- it's invasive, trying to run over well-established hostas, peonies, and herbs; I'm having a tough time killing it off.


On Sep 3, 2004, alaskagardengir from Anchorage, AK (Zone 4a) wrote:

Self propagrates occasionally. Grows wild in parts of AK, and is a looked-for wild flower in the early spring. Grows on sunny mountain sides and doesn't seem to require a lot of water. It is blue up here with small and larger specimens.


On Sep 3, 2004, CatskillKarma from West Kill, NY wrote:

There was a white cultivar in my garden when I moved in. The flowers are a little weedy-looking and grow on very long stems--some over five feet. The foliage is the same as the blue cultivars and very pretty. It is very vigorous and fights its way up through a mat of bishops weed that I have been unable to eradicate.


On Sep 1, 2004, penpen from North Tonawanda, NY (Zone 6a) wrote:

Grows very easily from seed. I think every seed that I winter sowed germinated. Has grown steadily all summer. Didn't bloom the first year. Looking forward to blooms next summer. In my yard it seems to grow the quickest in partial shade this year as we have had a lot of rain and very few sunny days overall. THe plants in more shade have been slower to grow.


On May 30, 2004, carolann from Auburn, NH wrote:

Four year old plant did not survive very cold winter which has frequent days and nights that hit between 0 and -20F. Not as hardy as noted in the entry here.


On Aug 26, 2002, smiln32 from Oklahoma City, OK (Zone 7a) wrote:

Splendid choice for cutting gardens, border edgings and rock gardens. Brightens shady areas. Plant in a well-drained locatoin and water generously. Protect from strong afternoon sun.


On May 4, 2002, Lilith from Durham,
United Kingdom (Zone 8a) wrote:

A handsome plant with long heads of hazy-blue showy flowers and finely divided foliage. When ripe, each anther bursts, releasing a mass of bright orange pollen, contrasting vividly with the blue of the petals. Creeping underground stems propagate the plant so that, given time, it forms extensive clumps. The common name derives from the ladder-like pattern made by the numerous parallel, narrow leaflets. A distant relative of the garden Phlox, Jacob's-ladder is widely cultivated for ornament, although many plants are the rarer white form, or an introduced variant with larger flowers. Until the Nineteenth Century in some parts of Europe, the species was thought to be effective in the treatment of syphilis and rabies. It was used in more ancient times against dysentry and toothache.


On Oct 27, 2001, Crimson from Clarksville, TN (Zone 6b) wrote:

Grows wild in England. It is a woodland plant for the shaded garden or for naturalizing in moist, leafy soil.