Phlox family (Polemoniaceae)
Description: This native perennial plant is 1–1½' tall, branching occasionally. The stems are usually glabrous and have a tendency to sprawl across the ground. They are often dull reddish green and somewhat angular. The alternate compound leaves are odd pinnate, consisting of about 5-15 leaflets, and they are up to 1' long. Sometimes, there are a few white hairs at the base of the petioles of the compound leaves. Each leaflet is oval to narrowly ovate, hairless, and with a margin that is smooth. It is about 1½" long and ½" across. Flowering stalks develop from the upper axils of the compound leaves that are several inches long. These stalks are glabrous and often reddish green, terminating in a small corymb of floppy or nodding flowers. Each bell-shaped flower is about 2/3" across. It has 5 rounded petals that are light blue, 5 stamens with white anthers, a style that is divided at its tip into 3 parts, and a reddish green calyx with 5 teeth that is united at the base. There are fine lines running along the length of the petals, while the stamens are the same length as, or shorter than, the petals. The blooming period usually occurs during the late spring and lasts about 2-3 weeks. The flowers are replaced by rounded capsules containing 3 cells. Each cell contains several seeds. The root system consists of a taproot. This plant spreads by reseeding itself.
Cultivation: The preference is light shade or partial sun, mesic conditions, and a rich soil with lots of organic matter. Full sunlight and conditions that are moister or drier are also tolerated. It is not aggressive, and adapts well to flower gardens, especially in partially shaded areas.
Range & Habitat: Jacob's Ladder is an occasional to locally common plant that occurs in most areas of Illinois, except for some counties in the central portion of the state (see Distribution Map). Habitats include deciduous mesic woodlands, woodland borders, mesic black soil prairies, fens, and semi-shaded areas along rivers. This plant prefers high quality natural habitats, and rarely wonders far from wooded areas.
Faunal Associations: The nectar and pollen of the flowers attract bees primarily, including honeybees, bumblebees, Little Carpenter bees, Mason bees, Cuckoo bees (Nomadine), Halictid bees (including Green Metallic), and Andrenid bees. A visitor from this last group, Andrena polemonii, is an oligolege of Polemonium spp. The flowers are also visited by Bombylius major (Giant Bee Fly) and various butterflies, skippers, or moths, which seek nectar. Syrphid flies also visit the flowers, but they feed on the pollen and are unlikely pollinators. Apparently, little information is available about this plant's relationships to birds and herbivorous mammals.
Photographic Location: A flower garden at Crystal Lake Park in Urbana, Illinois.
Comments: This is a rather floppy plant, although both the flowers and foliage are attractive. The bell-shaped flowers and compound leaves together provide Jacob's Ladder with a distinctive appearance. The only other species that resembles it, Polemonium vanbruntiae (Greek Valerian), which is native to some of the Eastern States, doesn't occur in the wild in Illinois. This latter species is more erect in habit, and has slightly larger flowers with exerted stamens. These flowers are usually a darker shade of blue than those of Jacob's Ladder, and their anthers are often yellow, rather than white. The common name of Polemonium reptans refers to the pairs of opposite leaflets on the compound leaves, which supposedly resemble a series of steps on a ladder in a dream by the biblical Jacob.