Photo by Melody

PlantFiles: 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)

3 vendors have this plant for sale.

31 members have or want this plant for trade.

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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)

Sun Exposure:
Light Shade
Partial to Full Shade
Full Shade


Bloom Color:
Medium Blue
White/Near White

Bloom Time:
Mid Summer


Other details:
This plant is attractive to bees, butterflies and/or birds
Requires consistently moist soil; do not let dry out between waterings

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

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There are a total of 27 photos.
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9 positives
4 neutrals
6 negatives

Gardeners' Notes:

Negative velmansia 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.

Positive ms_greenjeans 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.

Negative wendymadre 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.

Neutral akcrafter 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.

Positive burkgrow 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.

Positive trioadastra On Jun 5, 2008, trioadastra from Ellsworth, WI (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.

Negative mbhoakct76 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!

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

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

Positive rossmullion 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.

Positive fluffygrue 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.

Neutral elfmom 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!

Negative ccwales 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.

Positive alaskagardengir 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.

Positive CatskillKarma 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.

Positive penpen 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.

Negative carolann 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.

Positive smiln32 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.

Neutral Lilith 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.

Neutral Crimson 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.


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
Alden, New York
Nineveh, New York
West Islip, New York
West Kill, New York
Pembina, North Dakota
Akron, Ohio
Cincinnati, Ohio
Wren, Ohio
Portland, Oregon
Bellefonte, 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

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