Polemonium vanbruntiae - Britt.
Bog Jacob's-ladder
Other Common Names: Vanbrunt's polemonium
Synonym(s): Polemonium caeruleum ssp. vanbruntiae (Britt.) J.F. Davids.
Taxonomic Status: Accepted
Related ITIS Name(s): Polemonium vanbruntiae Britt. (TSN 504486)
Unique Identifier: ELEMENT_GLOBAL.2.143556
Element Code: PDPLM0E0L0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Phlox Family
Image 21774

© Elizabeth A. Byers

Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Solanales Polemoniaceae Polemonium
Check this box to expand all report sections:
Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Polemonium vanbruntiae
Taxonomic Comments: The species epithet formerly generally spelled 'van-bruntiae'; see cited example in ICBN (1988) Recommendation 73C.4(e): "vanbruntiae after Mrs. Van Brunt"
Conservation Status

NatureServe Status

Global Status: G3G4
Global Status Last Reviewed: 29Sep2005
Global Status Last Changed: 29Sep2005
Rounded Global Status: G3 - Vulnerable
Reasons: Polemonium vanbruntiae occurs in the northeastern United States, New Brunswick and possibly in Quebec, Canada. The major portion of the range of this species is in New York, where more populations are expected to be found. More than 100,000 stems are thought to occur. Threats to this species have to do with alteration of water regimes, ATV traffic and succession (this species requires some disturbance). Trends are considered stable over time.
Nation: United States
National Status: N3
Nation: Canada
National Status: N2 (13Nov2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Maine (S1), Maryland (S2), New Jersey (SX.1), New York (S3), Pennsylvania (S1), Vermont (S2), West Virginia (S2)
Canada New Brunswick (S1), Quebec (S2)

Other Statuses

Canadian Species at Risk Act (SARA) Schedule 1/Annexe 1 Status: T (12Jan2005)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Threatened (01Nov2002)
Comments on COSEWIC: Reason for designation: Few extant populations occupying very small habitats at risk from agricultural impacts, logging and other development pressures, and recreational activities.

Status history: Designated Threatened in April 1994. Status re-examined and confirmed in November 2002.

NatureServe Global Conservation Status Factors

Range Extent Comments: Narrow endemic; confirmed extant as of 2005 in Maine, Maryland, New York, Vermont, West Virginia, Pennsylvania, New Brunswick and Quebec. Known historically from New Jersey. Incorrectly identified and reported from Connecticut.

Area of Occupancy: 3-2,500 4-km2 grid cells
Area of Occupancy Comments:  

Number of Occurrences: 21 - 300
Number of Occurrences Comments: Maryland (9), New York (31), Vermont (9), West Virginia (19), Quebec (9), Maine (1), Pennsylvania (1). There is one population in New Brunswick, CA; this occurrence was rediscovered from the 1800s.

Population Size Comments: Historically, was reported as "locally abundant" in New York (House, 1923). Thre are easily more than 100,000 individuals, but propably not more than 1 million.

Number of Occurrences with Good Viability/Integrity: Some (13-40)
Viability/Integrity Comments: Twenty one occurrences with A or B ranks. Only three of the 19 occurrences in West Virginia are considered to have good viability.

Overall Threat Impact: Medium
Overall Threat Impact Comments: The major identifiable threats to this species are water regime perturbations (such as flooding), ATV traffic, heavy grazing and succession. Many of the sites are remote wetlands, so development is not considered a major threat to the species at this time.

One of Maryland's populations as well as one of Pennsylvania's were flooded by a recreational lakes. In West Virginia some occurrences are becoming shaded by succession and the lack of grazing (pers. comm. P. Harmon).

ATV use has been documented at very few sites, but many of the sites are vulnerable to such use, as well as to alteration by logging equipment.

Sites located in agricultural areas may be vulnerable to grazing, although occasional light grazing may benefit the species rather than harm it. It is unclear whether grazing animals (cattle or deer) eat POLEMONIUM VANBRUNTIAE; biologists have differing observations. One report suggests that grazing in one population has limited flowering (Harmon 1990); other biologists (Bartgis 1990 and Ed Thompson 1990) report seeing no evidence of grazing even in areas of heavy deer use.

There seems to be consensus among biologists familiar with this species that open wetlands are more suitable habitat than closed canopy wetlands. Therefore, succession may be a threat to some populations. Bartgis (1990) indicates that several West Virginia populations occur in areas which were grazed in the past, and he suggests that the plant may be in those areas as a consequence of openings created by grazing. Some of these areas may be threatened by succession. Many of the wetlands in which this species is found, however, are probably naturally open because of their water regime. In closed wetlands, natural perturbations such as windthrow provide openings in the canopy where the plant may colonize. While a subpopulation in one of these openings may become threatened by succession, other openings may appear and the plant presumably "moves around" within the wetland. None of this has been documented, however, so we can only cautiously assume that the plant does better in openings than in shade, and manage accordingly.

Populations in New Jersey and Pennsylvania have disappeared for unknown reasons. More information on these populations may help in determining threats to the species.

Some sites may face immediate danger due to development pressure and natural succession. At one site in New York, it was noted that few plants flower under heavy canopy but these plants produce many flowers where sunlight reaches the forest floor. More research is needed to determine how long these plants might survive under heavy canopy without any successful reproduction.

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Some populations are subjected to development are under threat (more info. is needed). Threats in Vermont include mowing (roadside mowing), however, populations are able to reseed themselves from unmowed portions.

Long-term Trend: Decline of <30% to increase of 25%
Long-term Trend Comments: Appears to be stable over time.

Intrinsic Vulnerability Comments: Tolerates and may respond favorably to logging and some other disturbances. This species responds well to some disturbance. Populations may flucuate year-to-year based on water level and light penetration, but plants seem to quickly rebound when conditions are right.

Environmental Specificity: Moderate. Generalist or community with some key requirements scarce.
Environmental Specificity Comments: Open marshed, hillside seeps and wet meadows. This species doesn't appear to require calcareous seepage as it occurs on shale and if confirmed in Quebec it would be on serpentine.

Other NatureServe Conservation Status Information

Global Range: Narrow endemic; confirmed extant as of 2005 in Maine, Maryland, New York, Vermont, West Virginia, Pennsylvania, New Brunswick and Quebec. Known historically from New Jersey. Incorrectly identified and reported from Connecticut.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States MD, ME, NJextirpated, NY, PA, VT, WV
Canada NB, QC

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
MD Allegany (24001), Baltimore County (24005)*, Garrett (24023), Harford (24025)
ME Washington (23029)
NJ Warren (34041)*
NY Chenango (36017), Cortland (36023), Delaware (36025), Herkimer (36043)*, Lewis (36049), Madison (36053)*, Montgomery (36057)*, Oneida (36065)*, Otsego (36077), Schoharie (36095), Sullivan (36105), Ulster (36111)
PA Berks (42011)*, Luzerne (42079), Somerset (42111)*, Sullivan (42113), Wayne (42127)
VT Addison (50001), Chittenden (50007)
WV Grant (54023)*, Mineral (54057)*, Pocahontas (54075), Preston (54077), Randolph (54083), Tucker (54093)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Maine Coastal (01050002)+
02 Mohawk (02020004)+*, Schoharie (02020005)+*, Upper Delaware (02040101)+, East Branch Delaware (02040102)+, Middle Delaware-Mongaup-Brodhead (02040104)+, Middle Delaware-Musconetcong (02040105)+*, Schuylkill (02040203)+*, Upper Susquehanna (02050101)+, Chenango (02050102)+, Upper Susquehanna-Tunkhannock (02050106)+, Upper Susquehanna-Lackawanna (02050107)+, Lower West Branch Susquehanna (02050206)+, Lower Susquehanna (02050306)+, Gunpowder-Patapsco (02060003)+*, North Branch Potomac (02070002)+
04 Salmon-Sandy (04140102)+, Oneida (04140202)+*, Black (04150101)+, Otter Creek (04150402)+, Winooski River (04150403)+
05 Conemaugh (05010007)+*, Tygart Valley (05020001)+*, Cheat (05020004)+, Youghiogheny (05020006)+, Greenbrier (05050003)+, Gauley (05050005)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
General Description: Jacob's-ladder is a tall erect plant that is easily seen when in flower. It grows up to 3 feet tall and has alternate leaves that sport a ladder-like arrangement of 7-10 pairs of lance-shaped leaflets and one terminal leaflet. The numerous nodding flowers at the top of the plant are quite striking with five deep blue-purple petals with yellow centers and long, bright yellow and white stamens that hang down.
Technical Description: Perennial herb of the Polemoniaceae, erect from a horizontal rhizome, 4-10 dm tall; leaves odd-pinnately compound, alternate; leaflets 15-21, distant (1-3.5 cm apart), narrowly ovate to ovate-lanceolate, short petioluled. Inflorescence a compact corymb with few flowers. Pedicels short-hirtellous, scarcely viscid; calyx with long divergent trichomes at base, its lobes lanceolate, acute; corolla open-campanulate, blue-purple, 1.2-1.5 cm long, stamens and style much exserted. Fruit a loculicidal capsule with three locules and 1-10 seeds per locule.
Diagnostic Characteristics: POLEMONIUM VANBRUNTIAE is frequently confused with P. CAERULEUM and P. REPTANS, two other Jacob's ladders found in the northeastern United States. P. REPTANS, a native species, has fewer leaflets (11-17) than P. VAN-BRUNTIAE, has openly branching inflorescences and has longer pedicels. P. CAERULEUM, introduces from Europe and naturalized in the U.S., has sessile leaflets (in P. VANBRUNTIAE the leaflets are short-petioled) and has stamens which are barely exserted, in contrast to P. VANBRUNTIAE's lon-exserted stamens. A technical manual such as Fernald (1950) should be consulted when identifying any specimen of POLEMONIUM.
Ecology Comments:

POLEMONIUM VANBRUNTIAE probably reproduces both vegetatively and sexually, although the relative importance of each is not known (and probably varies from site to site).

Plants spread vegetatively by means of horizontal rhizomes, and it may be that large clones are formed in this manner. A preliminary investigation by Elizabeth Thompson in one Vermont population showed that numerous stems were connected underground. The size of the clone was not determined but it may have been as large as several tens of square feet (hundreds of stems). In the same vicinity were observed plants that had clearly originated sexually (they were discrete plants or clumps). Other biologists have not observed obvious clonal behavior; in Maryland, Ed Thompson describes plants as clumped, suggesting that clones are quite small.

The pollination biology of the plant is unknown, but Popp (1990) describes the species as a self-incompatible perennial which is probably bee-pollinated. Both Ed Thompson (1990) and Elizabeth Thompson have observed bumblebees (BOMBUS sp.) visiting flowering plants. Flowers are protandrous (at least in one Vermont population), a possible outbreeding mechanism.

Seeds have been successfully grown under greenhouse and garden conditions. William Brumback of the New England Wild Flower Society collected seeds in Vermont in 1986. They did not germinate well immediately, but germinated well outdoors when held dry under refrigeration until the following spring (1987). Seeds held dry under refrigeration until November 1987 also germinated well outside. Other germination experiments with these seeds were erratic (Brumback 1989). Seedlings from these experiments have been transplanted into the wild in Vermont and have survived a single growing season with mixed results (Popp 1990). Long-term monitoring of this experiment will provide valuable information on the biology of the species.

Habitat Comments: POLEMONIUM VANBRUNTIAE occurs from New Brunswick and Quebec south to Maryland and West Virginia. It is nowhere common, but seems to be more abundant in New York state than anywhere else in its range. Approximately 19 current populations are known in West Virginia, totaling over 20,000 stems. In Maryland, approximately 9 populations total over 10,000 stems. The plant was known from a single historical site in New Jersey, and is presumed extirpated from that state. At least five historical populations were known in Pennsylvania; one of these was extant in 1986. One of the Pennsylvania populations (in the western part of the state) is known to have been destroyed by flooding. In New York, approximately 22 contemporary localities total over 50,000 stems. There are an additional 20 historical localities in New York. In Vermont, 5 small populations total over 1300 stems. Maine has a single known population, with fewer than 10 plants. Two contemporary and one historical population are known from the eastern townships in Quebec, but current field data are lacking (Lavoie 1991). A single population is known from New Brunswick, but it is not confirmed to be native (Hinds 1986).

POLEMONIUM VANBRUNTIAE is found in a variety of wetland habitats, including hardwood and softwood swamps, shrub swamps, marshes, bogs, lakeshores, woodland swales and seeps, spring runs, and wet roadsides, mostly at higher elevations (at least in the southern part of the plant's range). The Maryland populations (all in the western, mountainous part of the state) are at elevations between 2300 and 2700 feet. West Virginia populations are mostly at elevations of 2000-4000 feet. Elevations of New York populations range from 1190 to 3870 feet, with most of the populations between 1200 and 2500 feet. In Vermont, elevations range from approximately 350 to 1800 feet. It may be that elevations generally decrease with increasing latitude, but elevations of the Quebec and New Brunswick populations are not available to corroborate this.

It appears that this plant has a rather wide ecological tolerance; it is found in a variety of wetland types. Its rarity can probably not, therefore, be attributed to habitat scarcity. However, very little work has been done to actually quantify the habitat characteristics in successful or vigorous populations of this plant. Conversations with biologists familiar with the species point to some common features of habitats throughout its range: seepage water is a common (though not constant) feature; water is usually not standing above the surface for any significant period during the growing season (flooding seems to cause mortality); and open or partially open wetlands have the largest and most vigorous populations (the plant occurs in shaded sites, but populations tend to be small).

Ed Thompson (1990) and others have measured water pH at several populations in Maryland, finding pH levels of 6.6-6.7. Thompson describes the apparent ideal habitat as open areas influenced by circumneutral springs. He further proposes that the plant's pH range tolerance is rather narrow. Bartgis (1991) notes that most of the Maryland and West Virginia populations are associated with the Greenbrier limestone (the only major limestone formation in that area).


Careful descriptive work is needed before any conclusions can be drawn about the habitat requirements of this species range-wide.

Economic Attributes Not yet assessed
Management Summary
Stewardship Overview: This plant cannot be regarded as globally imperiled, but it is rare and worthy of protection and possibly of management.

More information is needed before management programs can be implemented, but it is suggested that opening of the canopy may be advantageous in some populations, and this should be investigated and experimented with.

Preliminary results from transplant experiments in Vermont are encouraging; it appears that seeds gathered in the wild can be germinated and grown under greenhouse/garden conditions and seedlings returned to the wild with at least some degree of success. More information from this experiment will be useful.

Restoration Potential: POLEMONIUM VANBRUNTIAE has been successfully raised under controlled conditions (Brumback 1989 and Popp 1990) from seed gathered in the wild, and seedlings have been transplanted to the wild with some success. All of the transplants (84 plants in all) survived the first summer, although some of them appeared more healthy than others at the end of the season. None showed evidence of having flowered.

Two transplant sites were used. One was an opening about 100 feet by 40 feet with 100 percent ground cover and little canopy cover. Dominant species were CAREX CRINITA and IMPATIENS CAPENSIS, and BETULA ALLEGHANIENSIS was scattered. In September, the soil at this site was wet and saturated to the surface with some standing water. Many of the transplants at this site were in fair or poor condition at the end of the first season. The second site was an opening about 220 feet by 40 feet, with less ground cover than the first but considerably more canopy cover. In September the soil was moist, but not completely saturated. Most of the transplants here were in very good or good condition (condition was assessed by number of dead leaves on the plant). Because the experiment lacked controls, no conclusions can be drawn regarding habitat preference. However, the experiment does provide some useful information and seems to indicate that the plant can be propagated under greenhouse conditions and transplanted to the wild. The transplants will be monitored in subsequent years, providing more information.

In Pennsyvania, a natural population was transplanted to another site when the original site was to be destroyed by a dam. The transplants have apparently not been successful (Wiegman 1991).

No other recovery experiments are known. It is presumed that some undesirable habitat alterations (such as increased canopy cover, human or bovine traffic, and minor hydrological changes) can be reversed with success, but no restoration experiments have been done in POLEMONIUM VANBRUNTIAE habitat.

Preserve Selection & Design Considerations: Protection of POLEMONIUM VANBRUNTIAE populations must be evaluated on a case-by-case basis.

Many of the populations seem to rely upon seepage water; in these populations protection of the water regime would be necessary to protect the populations. In some cases this may require protection of the entire watershed of the wetland in which the population lives.

In general, each population should be provided with enough habitat to insure that activities outside the protected area will not affect the plants.

Management Requirements: It is unknown whether active management would benefit this species, but habitat observations suggest that canopy opening in some populations might be beneficial. More information is needed to verify this.

It is suggested that in some representative shaded populations, limited experimentation with canopy opening be done, and the populations carefully monitored. In certain small, shaded populations (such as the single Maine population), this may be the only hope for securing the population.

Monitoring Requirements: Long term monitoring of some representative populations is needed to determine overall population trends, and to determine whether habitat changes (such as increased canopy closure) affect the populations.

For each population chosen for monitoring, 25 permanent meter-square plots, or as many as are feasible given the size of the population, should be established. Within each plot, water level and pH should be measured twice during the growing season (early summer and late summer, on some predetermined date), light should be measured on those dates in a standardized manner, percent cover of all species present should be determined on both dates, total number of POLEMONIUM VANBRUNTIAE stems should be counted, and number of flowering and fruiting culms should be counted in late summer, following flowering. Observation of pollinators should be made during flowering, if possible. Populations should be monitored in this way every three to five years, or more often if feasible.

Management Programs: No active management for this species is known. The work in Vermont (Popp 1990) is regarded as experimental only.
Monitoring Programs: No formal monitoring programs of natural populations are known in any of the states or provinces where this species occurs (see discussion of introduced population under RECOVERY-POT). The Maine Natural Heritage Program (Department of Economic and Community Development, Augusta, Maine, 04333) intends to initiate monitoring of Maine's single population.
Management Research Programs: In Vermont, a transplant experiment is underway to determine the success of transplanting garden-grown seedlings into the wild. See RESTOR.POTENTL above, and Popp (1990).
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 29Sep2005
NatureServe Conservation Status Factors Author: Losey, J.; rev. S.M. Young; E.H. Thompson (1991), rev. T. Weldy and L. Oliver
Management Information Edition Date: 03Jun1991
Management Information Edition Author: ELIZABETH H. THOMPSON
Element Ecology & Life History Edition Date: 03Jun1991
Element Ecology & Life History Author(s): E.H. THOMPSON (1991)

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  • Wherry, E.T. 1935. Polemonuim and Polemoniella in the eastern United States. Bartonia 17:5-12.

  • Wherry, E.T. 1935. Polemonium and Polemoniella in eastern States. Bartonia 17 5-12.

  • Wherry, E.T. 1935. Polemonuim and Polemoniella in the Eastern United States. Bartonia 17:5-12.

  • Wherry, E.T. 1935. Polemonuim and Polemoniella in the Eastern United States. Bartonia 17:5-12. A35WHE02PAUS.

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Note: All species and ecological community data presented in NatureServe Explorer at http://explorer.natureserve.org were updated to be current with NatureServe's central databases as of March 2019.
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Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

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Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

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"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

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IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

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