Jacob’s ladder, also known as Polemonium caeruleum (var. spelling coeruleum), is a hardy perennial herb of the Polemoniaceae family that includes phlox and gilia.
It seems to have come from Europe as an ornamental, seeded beyond its borders, and naturalized here. And, while there is evidence to suggest that it was used in medicinal applications in the past, P. caeruleum is not generally used as an herb today.
Other common names include charity, and Greek valerian, not to be confused with the “true” valerian plant, Valeriana officinalis.
And to further muddy the waters, this plant is often mistaken for P. reptans, a U.S. native also called Jacob’s ladder, as well as false Jacob’s ladder, creeping Jacob’s ladder, American Greek valerian, and abscess root. This variety is still used in herbal preparations.
Majestic in Blue
The upright stems of P. caeruleum rise regally, often to a height of three feet. Wispy leaves alternate, resembling the rungs of a ladder.
The petals of its clustered blossoms are a brilliant blue, a gorgeous example of nature’s rare blue flowers. Bright yellow stamens provide striking contrast.
P. caeruleum is a late spring to early summer bloomer. Like the hosta, it thrives in shade where there is rich, well-drained soil, and makes a great understory plant beneath trees.
Given the opportunity to go to seed, it will naturalize on your property, returning in greater quantity each year.
Polemonium caeruleum Plant Facts
- Blooms spring to early summer
- Naturalizes readily, invasive in some states
- Performs best in cooler regions
- Rich, well-drained soil, average moisture
- Shade to partial shade
- Up to three feet in height
- Zones 4 to 8
Where to Buy
P. caeruleum seeds are available on Amazon from Everwilde Farms.
Each package contains 100 seeds.
P. caeruleum is a striking flower that invigorates shady areas.
Plant it along stockade fences, to brighten the shadows they cast, and add structure to shorter plants arranged in the foreground.
How about welcoming visitors to your outdoor living space with tall spikes of brilliant blue flanking your garden gates?
For more ideas on bringing color into shady landscapes, see our article Choosing the Perfect Flowering Perennials: 5 for Your Shade Garden.
How have you added texture, color, and dimension to your gardens with shade-blooming perennials? Tell us in the comments section below.
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Product photo via Everwilde Farms. Uncredited photos: Shutterstock.
About Nan Schiller
Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!