How to Plant, Grow, and Care for Jacob’s Ladder

Jacob's ladder plant is an easy to grow, shade loving perennial. Botanically, Polemonium caeruleum, this flowering species has leaves that are set like a ladder. Learn about the best ways to care for this plant with Lorin Nielsen.

A bunch of jacob's ladder, appearing to have deep green foliage with dainty small flowers having a bright purple hue surrounded by other greens

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Once upon a time, Jacob’s ladder was called the “charity plant”, although it shouldn’t be confused with the Mahonia species that also bears that common name. It’s also been called “Greek valerian”, although it’s not a valerian. Confused yet?

Jacob’s ladder gets its common name from the ladder-like or pinnate structure of its leafy foliage. In the spring and early summer months, it shoots up slender stalks from which hang clusters of bell-like flowers.

A shade-loving variety, it has origins overseas but is often found in the United States in garden cultivation now. It’s such an easy-growing plant that it can even be considered slightly invasive if it’s in the right environment! However, it can be maintained and kept to its beds as well.

Let’s delve deep into the world of the Polemonium species, and I’ll tell you all about this beautiful perennial!

Plant Overview

A close-up shot of Polemonium caeruleumflowers forming sprigs with dainty purple blooms with soft petals placed in a sunny area
Plant Type Perennial
Family Polemoniaceae
Genus Polemonium
Species Polemonium caeruleum
Native Area Northern Europe, Scandinavia, North Asia
Exposure Full sun and partial shade
Height 1-2’
Watering Requirements Moderate
Pests & Diseases Leaf miners, slugs, cats, powdery mildew, fungal leaf spot
Maintenance Low
Soil Type Well-draining, rich
Hardiness Zone 4-9

What is Jacob’s Ladder?

Two species share the same common name. The one we’re focusing on today, Polemonium caeruleum, is the cultivated variety that can be found at your local garden center. Optimized for garden growing, it’s a highly-desirable burst of color in shadier locations.

A related species, Polemonium reptans, is called “false Jacob’s ladder” or “creeping Jacob’s ladder”. Native to the northeastern United States, it is considered a threatened wild plant in some states. Due to its tendency to be very leggy, it’s not ideal in a garden environment.

Native Area

Flowers of the Polemonium caeruleum placed in a sunny area, making the petals have a pale purple hue with vivid green leaves
They often appear in grasslands and wooded areas in Europe and Asia.

With its origins in the temperate regions of Europe and Asia, Jacob’s ladder is a beautiful addition to any garden. That’s largely why it’s become naturalized in multiple environments worldwide today, including eastern North America!

Jacob’s ladder is native to areas of meadowland, woodlands, and grasslands, this shade-loving species derives its name from its pinnate leaves that resemble the rungs of a ladder. It is an excellent low-maintenance plant that is often grown as a deer-resistant flower in many gardens.

Characteristics

A close-up shot of a Polemonium caeruleum, appearing to have many dainty and small flowers with a bright purple color with green leaves
Each cultivar can reach specific heights and widths.

Growing about 18-24 inches in height, Polemonium caeruleum often reaches a similar width to its height. Some cultivars can become even larger, up to about three feet tall. Most have dark green leaves.

The leaves of Jacob’s ladder may be fully, vibrantly green, and lush or may have other colorations. Examples of the variegated varieties are “Stairway To Heaven”, which has cream-colored foliage, or “Bressingham Purple”, which has deep green foliage streaked with dark purple.

Jacob’s ladder blooms in the spring to early summer months, often at the same time as allium species and the bleeding heart plant. Bell-shaped flowers hang in clusters from the end of their flower stalks and may range in color from blue to pink, yellow, purple or white.

For most of its preferred growing environments, Jacob’s ladder can easily be grown as a perennial. In some locations, it acts as a self-seeding annual. In eastern North America, this plant is perennial.

Planting

An area with healthy-looking stems of Polemonium caeruleum, having countless light purple flowers with soft-looking petals
These plants prefer to grow in shady spots that gets some sun.

Start by choosing a location that offers partial shade or dappled sunlight. The soil should be well-drained and rich in organic matter; composting the planting area will provide the nutrients necessary for healthy growth. Prepare the site by clearing weeds and loosening the soil to a depth of about 12 inches, creating an ideal environment for the roots to establish.

When it comes to planting, spring or early fall are the optimal times to plant Jacob’s ladder. Space the plants about 12-18 inches apart, allowing enough room to spread. Dig a hole slightly larger than the root ball and position the plant to level its crown with the soil surface, then backfill and water thoroughly. Mulch around the plants to help retain moisture and suppress weeds.

How to Grow

Easy to grow, it’s suited to beginning gardeners in a wide range of locations throughout the United States and Europe. As far as flowering plants go, this is a great starting choice!

Light

Vivid green stems of Polemonium caeruleum with dainty purple flowers, surrounded by bright green leaves with other plants in the background
They thrive in shady areas that receive just enough sunlight.

While I wouldn’t consider it to be a low-light plant, Jacob’s ladder prefers less light. It wants to grow in shady or semi-shaded spots, mostly because it can develop sunburn if it’s in too much direct sunlight.

Now, there are cultivars that are much more tolerant of direct sunlight than others. Green and leafy varieties are often more tolerant than the variegated-leaf varieties.

It can be difficult to strike the right lighting balance to promote flowering without damaging the plant’s leaves. If this is your situation, it’s best to opt for a healthy, foliage-dominant plant rather than try to push for heavy flowering. It will flower, just a bit less.

Water

A stream of water is directed at a dense cluster of green plants, with droplets glistening on the leaves as the spray reaches the top layers of the foliage.
Avoid overwatering because they suffer when puddles gather around the base.

This perennial prefers evenly moist soil conditions, but it won’t tolerate standing water. Therefore, it’s important to opt for well-draining soil to ensure that it doesn’t puddle around the plant.

Overall, the frequency of water should be gauged on how well the plant is developing. As a shade-tolerant species, there’s a bit less evaporation than if it were directly in the sunlight all day, which means your watering frequency varies depending on what lighting it gets.

Aim for consistency. Your plant is somewhat adaptable and in fact, can be quite drought-resistant once its roots are firmly established. It may require extra watering during the hotter months of the year, but otherwise, consistency is key.

Humidity can become a concern, as it’s prone to powdery mildew. Avoid wetting the leaves directly whenever possible, and provide good airflow around your plant.

Soil

Two hands cradling rich brown soil, fingers gently sifting through the earth. In the background, a soft blur hints at the vast expanse of fertile ground awaiting nurturing care and cultivation.
For these plants, soil with compost or organic plant material is ideal.

In regards to the soil, it loves soil that’s rich in organic material. Heavy applications of compost are recommended to make your plant thrive at its peak!

Before planting, blend in a good amount of compost to your planting bed to encourage ready growth. Make sure that the soil is still well-draining so that standing water doesn’t build up, as this can cause root rot to develop. Avoid or amend poor or clay-like soils.

While pH doesn’t appear to be a common issue, aiming for a neutral range is usually best for whatever other plants you decide to pair with it.

Temperature

A sprig of Polemonium caeruleum flowers viewed close up, appearing to have soft petals having a bright purple color
They tend to struggle in hot weather.

Jacob’s ladder is considered a shade perennial, but some varieties do act as annuals in cooler climates (hardiness zones below 6). Overall, the plant flourishes in zones 4-9 but can be grown in many more, even up to zones 10-11. It just needs to be in a more protected location if it’s hot.

Fertilizer

Close-up of a gardener's hand sprinkling organic granular fertilizer onto dark brown soil.
They don’t need fertilizer but can be beneficial for new growth.

If you apply a layer of compost around your plant a couple of times per year, it probably won’t need fertilizer at all!

However, if you do opt to use a separate fertilizer, aim for an early spring feeding with a balanced fertilizer. This promotes new growth. Feed again once the flowers have faded and the flower stalks are cut back to try to encourage another flush of flowering.

Maintenance

A stem of Polemonium caeruleum isolated from the bush, having vivid green color with lovely flowers near the top looking vibrant purple
They don’t need pruning unless to maintain their shape.

You won’t need to prune for any serious reason. Pruning Jacob’s ladder is mostly aesthetic in nature! If your plant is starting to get a bit leggy, you may wish to trim back excessive growth to keep it more evened up and visually appealing.

When deadheading spent flowers, cut the stalks to the base of the plant and wait for the flowers to fade first. If the weather conditions are good for producing flowers, this encourages them to rebloom.

Older plants may develop browned or beat-up, ragged-looking foliage towards the end of the summer months. You can prune out all of the damaged material, allowing the plant to fill back in with new growth.

Propagation

A bee attached to a stem of Polemonium caeruleum with vibrant purple flowers, surrounded by other greens in a sunny area
The most effective way to propagate them is by division or using seeds.

You can propagate with Jacob’s ladder seed, or do it by division. Cuttings may also work, but fail more often than they succeed.

Seeds should be sown directly into the soil after the risk of frost has passed in the spring. Cover them with a light dusting of soil and keep them moist until seedlings appear. Thin to 18 inches apart. Your plants produce lots of foliage in their first year and may not flower until subsequent years.

If you wish, you can allow your plant to go to seed, as it will readily self-seed its area. It comes back in a much denser distribution over time, and you may want to divide the plants later.

To divide your plants, carefully dig the plant out of the ground being especially careful not to damage its roots. Gently separate the rosette-like bases of the plant, teasing apart the root system. If necessary, you can cut especially entangled roots.

Replant your plants in freshly prepared soil and water them in thoroughly. Even if you don’t opt to divide your plants for propagation purposes and don’t allow them to self-seed, division should happen every three to four years. This ensures your plant has room to grow and develop.

Common Problems

Most pests don’t seem to care for it, but there are a few. Diseases also aren’t super-common but can happen. Here are some tips to help you if any problems arise!

Growing Problems

Multiple sprigs of Polemonium caeruleum flowers appearing a vivid purple, having vivid green stems and other greens in the background
Too much sun and heat can make them dry up.

As mentioned before, too much direct sunlight can cause foliage to get sunburned.  It’s not a bad idea to test the future location of your plant by placing a potted one in the location where you’re considering a permanent placement and seeing how it does there. If it’s good, plant away!

Too little water can cause the tips of the leaves to turn brown and crispy. While it’s surprisingly drought-tolerant once established, younger plants often experience this problem when underwatered. Stay consistent in your soil moisture.

As the heat of the summer reaches its peak, you may find that the foliage of your plant becomes less attractive. This is especially true if you’re growing in a hotter climate than zone 8. By the end of the summer, it may be leggy and browned in patches, requiring light pruning.

Pests

Closeup o an aspen leaf with white tunnels created by leaf miners, all around half of the leaf.
They can be vulnerable to leaf miners that leave distinct markings.

There are a very limited number of pests that seem to attack this plant. In fact, it’s deer-resistant and tends to be pest-resistant overall! But there are a few things which may find it to be tasty.

Leaf miners may come to visit. These little pests will chew lines through the leaves of your plant, and while the leaves are smaller than other types of foliage, it doesn’t stop them from making a quick meal on your plant. Remove damaged leaves as you notice them.

With these, it can be difficult to wipe them out. However, you can opt to repel them initially by regularly spraying all leaf surfaces with neem oil to keep the pests at bay. Introducing beneficial nematodes to your soil can help with killing off pupating adults.

Slugs are notorious for snacking on Jacob’s ladder, and they, too, can be difficult to stop. Use traps to lure these pests away from your plants.

Finally, two animals are enticed closer by this plant. Cats are especially attracted to younger plants, as they smell similar to catmint. In addition, groundhogs find the foliage absolutely delectable.

These two pests can be harder to repel than normal pests as they’re persistent. However, putting a wire cloche over your plant should deter them, as can a floating row cover. As your flowers also draw pollinators, a floating row cover is a temporary solution at best.

Diseases

Willow branches and leaves affected by Powdery Mildew appear coated with a white, powdery substance, causing the leaves to curl.
Excessive moisture could make them prone to diseases, such as powdery mildew.

Much like insects, very few diseases are likely to strike your plants. However, there are two which are fairly common.

Some fungal leaf spot conditions may persist in more humid conditions. While leaf spot diseases are generally not likely to kill your plant, they can make it hard for the plant to produce chlorophyll, which can slow its growth.

By and large, the most common disease for Jacob’s ladder is powdery mildew. This is also caused by moisture or humidity building up on the leaves and causing the right conditions for fungal growth. Neem oil is a great way to treat this condition on the plant’s dark green leaves and prevent further development.

In both fungal leaf spot or powdery mildew situations, you may be able to simply carefully remove the affected foliage and throw it out, preventing spread.

Frequently Asked Questions

Where is the best place to plant Jacob’s ladder?

Plant them in an area where you can keep the soil moist but well-draining and in a spot where there is some shade.

Is Jacobs ladder a shade plant?

Yes, it enjoys more shade than many plants.

Does Jacob’s ladder bloom all summer?

The blue flower of this lovely plant tends to die back as the heat of summer sets in.

Should Jacob’s ladder be cut back?

As the flowers finish blooming, feel free to deadhead spent flowers as they crop up. Or cut them back if they’re getting leggy.

How deep do you plant Jacob’s ladder?

Press seeds of Greek valerian plants into the ground and lightly cover them with no more than an eighth of an inch of soil.

Is Jacob’s ladder poisonous?

Yes. Do not consume it, and keep it away from pets and children.

How do you winterize a Jacob’s ladder?

Cut them back to the ground in summer, and cover them with a layer of mulch. This will keep the soil moist and protect the roots in winter.

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