Jennifer Schultz Nelson
Extension Educator, Horticulture
I am a sucker for plants with variegated foliage. Somehow they always tend to come home with me, especially if they will work in my small shade garden. Since I live in a new subdivision, most plants I grow must be able to tolerate scorching sun and thrashing winds. I have one little protected nook on the north side of our home which can sustain shade loving plants. Variegated Jacob's Ladders have worked nicely in this area.
There are several Polemonium species in cultivation, but the most commonly grown species is Polemonium caeruleum. This species is native to grasslands, woodlands, and meadows in temperate regions of Europe and is hardy all the way to Zone 2.
Another common name for Jacob's Ladder is Greek valarian. Ancient Greeks reportedly used the plants medicinally for a variety of problems including dysentery, toothache and animal bites. In the 1800's some European pharmacies also used the plant to treat syphilis and rabies. Today, Jacob's Ladder is not commonly used medicinally.
The name Jacob's Ladder comes from the description of a ladder to heaven described in the book of Genesis in the Bible. As a common name for Polemonium, this name refers to the foliage's resemblance to a ladder. The leaves are pinnately compound, meaning they have a stem-like vein in the center and leaflets attached on either side, like rungs of a ladder. They add a lot of texture to the shade garden, particularly when planted near large-leaved hosta cultivars.
The leaves of Jacob's Ladder may be plain green, or variegated. The variegated cultivar that first caught my eye was Polemonium reptans 'Stairway to Heaven' which has pink and cream colored edges of each leaflet. The pink variegation is most vibrant in cooler weather. I'm not sure whether the breeder was a Led Zeppelin fan, or named the cultivar in reference to Jacob's ladder of the book of Genesis leading to heaven, but it is quite striking as it emerges in the early spring garden. It is considered to be a creeping Jacob's ladder, fairly low-growing at ten to sixteen inches high. It is flowering in my garden now with nodding blue flowers above the foliage.
My newest addition is the Polemonium caeruleum 'Brise d'Anjou' which has leaves heavily edged with cream colored variegation. It grows to about eighteen to twenty –four inches high. It blooms with violet-blue flowers.
Jacob's Ladder is also grown for its flowers. The flowers are borne on spikes above the foliage. The flowers are five-petaled and cup-shaped, and hang from the spike, giving a nodding appearance. The most common flower color is blue, although there are a few other colors available, including: white (P. caeruleum album), pink (P. reptans 'Pink Dawn') and blue with apricot centers (P. carneum 'Apricot Delight').
The best growing site for Jacob's Ladder is one with well-drained soil, and regular watering until the plant is established. Mulch the plant to keep the roots cool.
Some plant tags for Jacob's Ladder list the plant as suitable for full sun locations. Sources I have found suggest full sun only in locations where summers are cool, eliminating central Illinois for sure. The first Jacob's Ladder I bought was P. boreale 'Heavenly Habit' which had large blue flowers perfect for my full sun Illini garden. The tag said full sun to part shade. Not knowing much about Jacob's Ladder, I planted it in the Illini garden, thinking since the tag said full sun it would be fine. It did OK for awhile, but by the end of summer it was toast. I saw no sign of it this spring. My other Jacob's Ladders are in my shade garden which gets some morning sun, and they're doing great.
I've heard varied reviews from gardeners, some saying they "never have luck" with Jacob's Ladder, others loving the plant. The most likely reason for Jacob's Ladder failing in the garden is location. If they get too hot, like mine did in full sun, they are not likely to survive the season, let alone overwinter successfully. They need a location in at least partial shade for success. I've hopefully learned my lesson on growing Jacob's Ladder.