Plant of the Week

Polemonium viscosum range map.
Polemonium viscosum range map. USDA PLANTS Database.

Polemonium viscosum
Sticky polemonium is a magnificent, uplifting, eye-opening surprise for visitors to the western high mountains in the spring and early summer. Photo by Charlie McDonald.

Polemonium viscosum
Sticky polemonium flowering on a south-facing slope as the snow recedes from the high peaks east of Silverton, Colorado. Photo by Charlie McDonald.

Sticky Polemonium (Polemonium viscosum)

By Charlie McDonald

Sticky polemonium, also frequently called sky pilot, is a member of the phlox family (Polemoniaceae), which has about 400 species in 18-25 genera. The majority of the phlox family grows natively in western North America. The diversity of species and genera is particularly high in California where 17 genera and over 170 species occur. The family has little economic importance, but includes many popular garden ornamentals. All but the smallest-flowered genera have species suitable for cultivation in rock gardens, container gardens, formal borders, and naturalized wildflower areas. However, only Phlox (moss pinks, garden phlox, wild sweet Williams) and Polemonium (Jacob's ladder, sky pilot) are commonly available for use in home gardens.

Thomas Nuttall first collected sticky polemonium near the headwaters of the Platte River on his 1834-1837 western wanderings; he named and described the plant in 1848. Nuttall (1786-1859) was a British botanist and intrepid explorer of the American West. He collected thousands of plants, many of them new to science, and gave them names in a variety of scholarly works published during the first half of the nineteenth century.

Sticky polemonium is at home in the high mountains above 9,000 feet and in alpine tundra throughout much of the West. It likes rocky south-facing slopes and scree areas where the snow melts early and the soils warm up. The plant is an herbaceous perennial with intensely blue/purple flowers. Its leaves are succulent appearing, finely cut, upright, and often quite numerous in comparisons to the number of flowers. The name viscosum refers the sticky leaves.

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