by Matt Gibson
Jacob’s ladder (Polemonium caeruleum) is a popular choice for beginning gardeners due to its hardiness and easy care instructions as well as its beautiful light blue to dark purple flowers. Jacob’s ladder is a relatively pest-resistant and low maintenance plant.
Though known primarily for its colorful blooms, Jacob’s ladder actually gets its name from the shape of its leaves. The plant forms a clump of tightly packed leaf stems, which each contain tiny leaflets. These leaflets rise along the stem somewhat like a ladder, and the full name is a reference to the ladder in Jacob’s Biblical dream. This leaf formation is known as a pinnate and is relatively uncommon among flowering plants.
The first word of the official botanical name, polemonium, comes from the from the Greek name for the plant, polemonion, which is a reference to the Greek philosopher Polemos of Cappadocia. In Latin, the species name simply means “most handsome,” a title the flowering perennial has certainly earned. The genus name of Jacob’s ladder is attributed to several namesakes, including King Polemon of Pontus and an early philosopher from Athens of the same name. The Greek word “polemos” also means war. A Roman scholar by the name of Pliny the Elder wrote that the name “Polemonium caeruleum” originally came from the war created by the rivalry between two kings who both claimed that they were the first to discover the Jacob’s ladder plant’s medical value. The Native American name for Jacob’s ladder translates to “smells like a pine” which doesn’t describe the scent of the flowers themselves, but their roots.
Varieties of Jacob’s Ladder Flowers
There are two different types of Jacob’s ladder: one common to gardening and one that grows in the wild. The wild one, Polemonium reptans, is considered a threatened species in some states. Therefore, growing it at home is discouraged as a way to keep gardeners from taking cuttings from wild plants to add to their collections. Polemonium caeruleum, also known as Greek valerian, was developed specifically for growing in the garden and is available in many different shades, sizes, and varieties. Here are a few of our favorites.
Polemonium Snow and Sapphires:
Similar to the popular Brise d’Anjou variety but hardier and more resistant to pests, the Snow and Sapphires variety is a no-brainer choice. The Snow and Sapphires plant shows off variegated leaves with bright blue flowers. Hardy in USDA zones 5 to 8, this variety grows to 24 to 30 inches in height.
Clusters of white bell-shaped flowers with long yellow stamens sit atop mid-green foliage. The Album variety is a wonderful standout flower for late spring and early summer blooms and is hardy in zones 3 through 8.
Polemonium Stairway to Heaven:
Bright blue flower clusters sit atop variegated leaves that tend to blush pink in cooler weather conditions. The pink tint really brings the plant to life in zones 4 through 8. Stairway to heaven reaches only 12 to 24 inches in height.
Polemonium Bambino Blue:
The Bambino Blue variety is sure to catch the eye of passersby because of its beautiful light blue flowerhead and big yellow central eye with elongated stamens. One of the most compact varieties, Bambino Blue is hardy in zones 3 to 9.
Polemonium Bressingham Purple:
The Bressingham Purple variety tops out at two feet, with violet-blue flowers and brightly variegated foliage that forms clumps that range from one foot to a foot and a half wide. The foliage sets this variety apart from others with similar colors. Bressingham purple is hardy in zones 4 to 8.
This dwarf variety only grows as high as three inches to one foot. In late spring, it produces small purple or blue flowers. Native to areas near the Arctic circle, this smaller variety is hardy from zones 3 to 9 and flowers in late spring.
Growing Conditions for Jacob’s Ladder / Polemonium Caeruleum Flowers
Jacob’s ladder is a woodland perennial that generally prefers a shady to semi-shady spot, as the leaves tend to scorch and burn with too much direct sunlight exposure. Jacob’s ladder thrives in soil that is rich in organic material and a consistently moist but not soggy environment, especially while it is establishing its root system. Once the roots are established, the plant is actually quite resistant to drought.
Moist soil doesn’t mean boggy, though. The soil where you grow Jacob’s ladder needs to be well-drained and never fully wet, as this flower will not live long in standing water. The plant is much more fussy about moisture conditions in the soil than it is regarding pH, but the best results will be seen in a loose, rich soil with a pH balance between 6.2 and 7.0, a nearly neutral range, which makes it a great planting companion for a ton of different springtime flowers.
Where to Plant Jacob’s Ladder
Once you have located a spot that is suitable to the needs of Jacob’s ladder and gotten the plants adjusted to their new homes, there are very few flowers that are easier to grow. Varieties with dark to mid-green leaves can handle more sunlight than varieties with variegated foliage.
How to Plant Jacob’s Ladder
Plant division is the recommended method for planting Jacob’s Ladder, but you can have great results growing from seed as well. After all danger of frost has passed, sow the tiny brown seeds directly into the ground. Sprinkle some light soil over the seeds, and keep them moist until you start to see sprouts. Seeds tend to germinate very quickly and should be thinned until one plant stands every 18 inches or so. If you’re planting from seed, you can expect to see a fine burst of foliage on the first year of growth, but you may not see any blooms until the second year.
Care for Jacob’s Ladder Flowers
Jacob’s ladder care is simple to say the least. After blooming, the stems may become a bit leggy and could benefit from some light trimming. After a few years, some foliage will start to become discolored or unsightly. Simply trim away all unbecoming leaves, and you will start to see new growth sprout up almost immediately. Deadhead after the first blooms appear in late spring.
Division is the only laborious bit of care that gardeners may choose to invest in their Jacob’s ladder plants, and it should be undertaken in the early spring each year, just as new growth starts to take place. At this point, carefully dig around the plant and remove the entire thing, roots and all, from the earth. The rosettes must then be separated by tearing the roots apart and replanting each plant separately. This is also a great time to add a bunch of organic material into the soil for the new blooming season. Water the divided transplants well, and keep them moist for a few weeks to give them ample time to recover from the shock and adjust to their new plots.
Though it is usually not an issue, larger varieties of Jacob’s ladder can eventually start to droop or become leggy, and can benefit from staking. Judge for yourself whether you want a more upright plant or don’t mind them bowing a bit. Staking is recommended especially in if your plants are in an area where they’ll be exposed to lots of high-speed winds.
Garden Pests and Diseases of Jacob’s Ladder
Jacob’s ladder is resistant to most insect infestations and diseases. It’s also deer and rabbit resistant, so you don’t have to worry about nibbling wildlife snacking on your blooms. Sun scorch is actually the most common problem with the flower’s foliage, as some mistakenly plant it in a location with insufficient afternoon shade. Too little water can also cause the leaves to brown at the tips. Possible issues gardeners occasionally encounter include leafminers, slugs, leaf pot, and powdery mildew.
Companion Planting for Jacob’s Ladder
Jacob’s ladder starts to bloom around the same time as many other flowers. Therefore, alliums, bleeding heart, and Brunnera are wonderful companion flowers for it in the flower bed—and their colors are also very complementary. The dainty, airy branches of Jacob’s ladder plants are a nice textural contrast to the more substantial leaves of Brunnera. Hosta is another excellent companion plant, as its leaves may still be unfurling as Jacob’s ladder starts to produce its first buds in late spring.
Want to Learn More About Jacob’s Ladder?
Check out this video for an in-depth guide on how to grow Jacob’s ladder:
This video from Garden Time TV features Jacob’s ladder, a springtime favorite in the Pacific Northwest:
This video contains detailed care instructions for dwarf varieties of Jacob’s ladder:
This short video gives you a close-up view of Jacob’s ladder, in showy blue:
Angelfire covers Jacob’s Ladder
Better Homes & Gardens covers Jacob’s Ladder
Gardener’s Path covers Jacob’s Ladder: Regal Shade-Blooming Perennial
The Garden Helper covers Polemonium
Gardening Know How covers Growing Jacob’s Ladder
HomeGuide SFGate covers How to Care for a Jacob’s Ladder Plant
The Spruce covers Growing Spring Blooming Jacob’s Ladder